SIMS College of Pharmacy, Mangaldas Nagar, Vijayawada Road, Guntur-522001. A.P., India.
Ofloxacin is an antibiotic used to treat bacterial infections in many different parts of the body. The official method of analysis of Ofloxacin is potentiometric method. Several UV spectrophotometric, HPLC methods in pure form, pharmaceutical formulation and HPTLC methods have been reported to determine. This review provides an overview of various analytical techniques used for Ofloxacin determination both in a single preparation and in combination.
Ofloxacin
Ofloxacin is a quinolone antibiotic useful for the treatment of a number of bacterial injections. When taken by mouth or injection into a vein, these include pneumonia, cellulitis, urinary tract infections, prostatitis, plague, and certain types of infectious diarrhoea. It’s also an antibacterial agent used for the treatment of bacterial infections in many parts of the body, including the respiratory tract, kidney, skin, soft tissue, and urinary tract.[1]
Fig. 1: Structure of Ofloxacin
Chemical Formula of Ofloxacin is C18H20FN3O4, [2]
Absorption: Bioavailability of ofloxacin in the tablet formulation is approximately 98%. Metabolism was found to be Hepatic. Its IUPAC Name was 7-fluoro-2-methyl-6-(4-methylpiperazin-1-yl)-10-oxo-4-oxa-1-azatricyclo [7.3.1.0^ {5,13}] trideca-5(13),6,8,11-tetraene-11-carboxylic acid with the Melting point of 254 ºc having Water solubility of 28.3 mg/mL.[3]
Drug Interactions
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.it also has several side effects that are Bradycardia (slow heartbeat) ,Diabetes, Diarrhoea, Heart disease or Heart rhythm problems (e.g., prolonged QT interval), or family history of or Hypokalaemia (low potassium in the blood), uncorrected or Myocardial ischemia (reduced blood supply in the heart) or Seizures (epilepsy), or history of—Use with caution. May make these conditions worse.[4]
Therapeutic Categories
Mechanism of action
Ofloxacin acts on DNA gyrase and topoisomerase IV, enzymes which, like human topoisomerase, prevents the excessive supercoiling of DNA during replication or transcription. By inhibiting their function, the drug thereby inhibits normal cell division.
Pharmacokinetics
Analytical Methods
HPLC
A sensitive HPLC method has been developed for determination of ofloxacin (OFL) in biological fluids. Sample preparation was performed by adding phosphate buffer (pH 7.4, 0.1m) then extraction with trichloromethane. OFL and the internal standard, sarafloxacin (SAR), were separated on a reversed-phase column with aqueous phosphate solution-acetonitrile, 80?20, as mobile phase. The fluorescence of the column effluent was monitored at λmax 338 and λmax 425 nm. The retention times were 2.66 and 4.24 min for OFL and SAR, respectively, and the detection and quantitation limits were 8 and 15 ng mL−1, respectively. Plots of response against ofloxacin concentration were linear in the range 8 to 2000 ng mL−1. Recovery was 92.9% for OFL. [4] A simple, selective, rapid, precise and economical reverse phase high-pressure liquid chromatographic method has been developed for the simultaneous estimation of Ofloxacin and Ornidazole from pharmaceutical formulation. The method was carried out on a Kromasil C18 (5 mm, 25 cm X 4.6 mm, i.d.) column, with a mobile phase consisting acetonitrile: phosphate buffer (pH 2.4) in the ratio 80: 20% V/V at a flow rate of 1.0 ml/min. Detection was carried out at 294 nm. The retention time of Ofloxacin and Ornidazole were 2.773 and 5.448min respectively. The developed method was validated in terms of accuracy, precision, linearity, Limit of detection, Limit of quantitation. The proposed method can be used for estimation of these drugs in combined dosage form for routine analysis.[5] A simple, sensitive, and accurate chromatography (RP-HPLC) method for simultaneous estimation of Ciprofloxacin, Ofloxacin, and Marbofloxacin in their combined pharmaceutical dosage form or individually. The HPLC separation was achieved on a Hypersil (C18, 150 mm × 4.6 mm, 5 μm particle size) analytical column or equivalent. A mixture of triethanolamine (1 %), acetonitrile (80 %), and water was used as the mobile phase, with a flow rate of 1.2 mL /min and a detector wavelength of 280 nm at ambient temperature. In the HPLC method, the retention times of Ciprofloxacin, Ofloxacin, and Marbofloxacin were found to be 1.854, 2.480, and 4.688 min, respectively, and linearity was obtained in the range of 25–80 µg/mL for Ciprofloxacin, Ofloxacin, and Marbofloxacin. The correlation coefficient for the method was greater than 0.999. The RP-HPLC method validation parameter lay within its acceptance criteria as per the ICHq2 (R1) guideline. Hence, it can be successfully used for routine analysis of Ciprofloxacin, Ofloxacin, and Marbofloxacin in raw material or pharmaceutical dosage forms.[6] The present paper describes a novel, isocratic, simple, precise, accurate, and robust reversed-phase high-performance liquid chromatographic (RP-HPLC) method development and validation for simultaneous quantitative estimation of Ofloxacin and Beclomethasone dipropionate in an Ophthalmic/Otic formulation. The proposed chromatographic estimation was carried out isocratically using Protonsil C18 (250 × 4.6mm) SH 5.0µm column, the mixture of 0.02 M potassium dihydrogen phosphate buffer (pH adjusted to 3 using ortho-phosphoric acid): acetonitrile in a ratio of 30:70 v/v with a flow rate of 1 mL/min was used as mobile phase and column oven adjusted to 30°Cwith injection volume 10µL. The ultraviolet (UV) detection was carried out at 234 nm. The retention time of ofloxacin and beclomethasone dipropionate was found to be 2.67±0.2 min and 7.42±0.2 min, respectively. Calibration curves were linear over the tested concentration range of 4 to 20µg/mL. The present study reveals that this novel isocratic HPLC method is well-validated, reliable, and can be used for routine analysis of ofloxacin and beclomethasone dipropionate in an otic formulation containing these as one of the ingredients.[7] An accurate, precise and robust isocratic HPLC method has been developed and validated for simultaneous determination of Rifampicin and Ofloxacin. The chromatographic separation was carried out on Kinetex C18, 100 A Phenomenex column with a mixture of 0.03M Potassium dihydrogen phosphate buffer pH 3.0: Acetonitrile (55:45) as mobile phase at 230 nm. The retention times were 2.91 and 4.87 min for Ofloxacin and Rifampicin, respectively. Calibration plots were linear over the concentration range 1–5 and 2–10 µg/ml for Rifampicin and Ofloxacin, respectively. The method was validated for linearity, sensitivity accuracy, precision, and robustness. Percent recoveries were found to be close to 100% with low variability. Fractional factorial design with four factors was chosen for robustness testing. The volume of acetonitrile and flow rate showed significant effect on retention factor of both the drugs and asymmetry factor of ofloxacin. The method may be adopted for routine analysis at industry. [8] The objective of this work was to develop and validate simple, rapid and accurate chromatographic methods for simultaneous determination of ofloxacin and ornidazole in solid dosage form. The first method was based on reversed phase high performance liquid chromatography, on Intersil C18 column (250 mm, 4.6 i.d.), using acetonitrile: methanol: 0.025M phosphate buffer, pH 3.0 (30:10:60 % v/v/v) as the mobile phase, at a flow rate of 1 ml/min at ambient temperature. Quantification was achieved with UV detection at 318 nm over a concentration range of 2-40 µg/ml for ofloxacin and 5-100 µg/ml for ornidazole. The mean retention time of ofloxacin and ornidazole was found to be 4.04 min and 5.83 min, 6.77 min (isomers), respectively. The amount of ofloxacin and ornidazole estimated as percentage of label claimed was found to be 100.23 and 99.61%, with mean percent recoveries 100.20 and 100.93%, respectively. The second method was based on TLC separation of these drugs using silica gel 60F254 aluminium sheets and dichloromethane: methanol:25% ammonia solution (9.5:1:3 drops v/v) as mobile phase. Detection was carried out at 318 nm over the concentration range of 20-100 ng/spot for ofloxacin and 50-250 ng/spot for ornidazole. The mean Rf value of ofloxacin and ornidazole was found to be 0.16 and 0.56, 0.78 (isomers), respectively. The amount of ofloxacin and ornidazole estimated as percentage of label claimed was found to be 100.23 and 99.61% with mean percent recoveries 100.47 and 99.32%, respectively. Both these methods were found to be simple, precise, accurate, selective and rapid and could be successfully applied for the determination of pure laboratory prepared mixtures and tablets. [9] A simple, rapid, and accurate reversed phase high-performance liquid chromatographic (RP-HPLC) method has been developed and subsequently validated for the simultaneous determination of ofloxacin (OFL) and satranidazole (SAT) in combination. The separation is carried out using a mobile phase consisting of 10mM phosphate buffer and methanol in the ratio of 50:50. The pH of the mobile phase is adjusted to 3.0 with 10% o-phosphoric acid. The column used is Kromasil-100 C18 (250 × 4.6 mm, 5 µm). with flow rate of 1.0 mL/min using UV detection at 294nm. The total run time is 5 min and the retention time of OFL and SAT is 2.59 min and 4.0 min respectively. The described method is linear for the assay of OFL and SAT over a concentration range of 10–24 µg/mL and 15–36 µg/mL respectively. Results of the analysis have been validated statistically and by recovery studies. The limit of quantitation for SAT and OFL has been found to be 0.042 µg/mL and 0.085 µg/mL respectively. The results of the studies showed that the proposed RP-HPLC method is simple, rapid, precise, and accurate, which is useful for the routine determination of SAT and OFL in bulk drug and its pharmaceutical dosage form.[10] Rapid and accurate reverse phase high performance liquid chromatography method is described for determination of ofloxacin from the bulk drug and pharmaceutical dosage form. It was observed that Polaris C18 (15 x 4.6 mm i.d.) with 5 µ particle size column showed most favourable chromatographic pattern over the other columns. The mobile phase consisted of buffer and acetonitrile (80:20 % v/v). The buffer was mixtures of 0.01 M ammonium acetate adjusted the pH 3 with ortho-phosphoric acid. The detection was carried out at wavelength 294 nm. The method was validated for system suitability, linearity, accuracy, precision, robustness and stability of sample solution with the linear range 10-30 µg/ ml. The method has been successfully used to assay of pharmaceutical dosage form i.e. tablets with good recoveries. [11]
UV Spectroscopy Method
Ofloxacin is used to treat a bacterial infection. It is indicated for the treatment of adults with mild to moderate infections triggered by susceptible strains of the nominated microorganisms in the infections likes acute bacterial exacerbations of chronic bronchitis, community acquired pneumonia, uncomplicated skin and skin structure infections, acute, uncomplicated urethral and cervical gonorrhoea, nongonococcal urethritis and cervicitis, mixed infections of the urethra and cervix, acute pelvic inflammatory disease (including severe infection), uncomplicated cystitis, complicated urinary tract infections and prostatitis. The most common side-effects are feeling sick, diarrhoea, feeling dizzy and headache. Spectrophotometry is regarded as by its speed and simplicity, accuracy and inexpensive instrument needed, and hence it is a significant substitute to further analytical methods, through clear advantages in terms of cost of analysis. Assay of Ofloxacin tablets is carried out by a rapid, simple, accurate, and economical least time-consuming spectrophotometric method and then compares it with the assay of two different brands available in Karachi, Pakistan. Results of assay reveal that both trademarks of Ofloxacin are bioequivalent and are within the endorsed range. Brand A shows a percent assay of 100% while Brand B shows low value for percentage assay that is 96.31%.[12]
UV–Vis absorption Spectro electrochemistry has been selected as a suitable Mult response technique to determine the fluoroquinolone ofloxacin in urine samples without any previous pretreatment. Due to the modification of the working electrode surface during the oxidation of this antibiotic, the electrode has to be replaced or polished between measurements. A new Spectro electrochemistry cell has been developed, which allows in a simple way to perform reproducible experiments with different screen-printed electrodes. The new cell has been used to perform analysis in a complex matrix such as urine. Due to the trilinear character of the Spectro electrochemical data, PARAFAC has been used to determine ofloxacin with very good figures of merit, demonstrating the capability of trilinear methods to avoid the influence of some interfering compounds.[13]. The present work was aimed to develop two simple and sensitive UV spectrophotometric methods for the estimation of ofloxacin in bulk and in dosage forms. Ofloxacin is one of the most promising newer members of the fluoroquinolone family of antibacterials. Ofloxacin shows the absorption maxima at 284.0 nm in pH 6.8 phosphate buffer and 286.0 nm in pH 7.2 phosphate buffer with an apparent molar absorptivities of 4.1558 x 104 and 3.0717 x 104, respectively and obeyed the Beer’s law in the concentration range of 1-6 µg/mL and 1-10 µg/mL. Both the proposed methods were applied for the estimation of different ofloxacin tablets with mean percent accuracies of 99.2 ± 3.1 and 104.6 ± 1.89, respectively with method A and 99.01 ± 0.45 and 99.24 ± 0.34, respectively with method B. [14] The aim of present work is to develop and validate simple, sensitive, economical and accurate Spectrophotometric method has been developed for determination of Ofloxacin in pure form and in pharmaceutical formulations. Ofloxacin in methanol shows maximum absorbance at 294 nm. The drug obeyed Beer's law in the concentration range of 15μg/ml in methanol. The proposed methods were successfully applied for the determination of drug in commercial tablet preparations. The results of the analysis have been validated statistically and by recovery studies.[15] A simple, sensitive, rapid, accurate and precise simultaneous UV-spectrophotometric method was developed for the estimation of nitazoxanide and ofloxacin dosage form. Ratio of absorbance at two selected wavelengths, one of which an is absorbance point and being the? max of the one of the two components. Ofloxacin has absorbance maxima at 300nm and nitazoxanide has absorbance maxima at 344nm in Ethanol. The is absorbance point of ofloxacin and nitazoxanide was found to be 347nm. Linearity was obtained in the concentration range of 2-25µg/ml for each nitazoxanide and ofloxacin Result of analysis have been validated statically and by recovery studies. [16] Ofloxacin belongs to the class of Fluoroquinolone antibiotics. This class of antibiotic is used for the treatment of both gram positive and gram negative bacterial A Simple, easy, economical and quantitative analytical method has been applied for the determination of ofloxacin using active and pharmaceutical dosage form with 2 different brands including Oflox400mg tablets manufactured by Indus Pharma Batch # 1008 and Tarivid 200mg tablet manufactured by Sanofi Aventis Batch # WD057. The maximum absorbance was detected at wavelength 294 nm using distilled water as a solvent. The linearity of the method was analysed, ranging from 3.125ppm to 25 ppm and is found to be satisfied. Beers law was observed in the concentration range of 3.125-25 ppm with correlation coefficients 0.988, 0.998, 0.920 for standard, Oflox and Tarivid respectively which meet the criteria mentioned in the ICH guide lines (Figure 2-4). The linear regression equation obtained by least square regression method were y = 0.073x + 0.105 for active, y = 0.111x + 0.199 for Oflox and y = 0.12x + 0.527 for Tarivid which also meet the criteria mentioned in the ICH guide lines, where y is the absorbance and x is the concentration of the pure drug solution.[17] Simple, precise, economical, fast and reliable two UV methods have been developed for the simultaneous estimation of Cefixime Trihydrate and Ofloxacin in bulk and pharmaceutical dosage form. Method A is Absorbance maxima method, which is based on measurement of absorption at maximum wavelength of 287 nm and 296 nm for Cefixime Trihydrate and Ofloxacin respectively. Method B is area under curve (AUC), in the wavelength range of 265-301 nm for Cefixime Trihydrate and277-320nm for Ofloxacin. Linearity for detector response was observed in the concentration range of 5-25μg/ml for Cefixime Trihydrate and 5-25 μg/ml for Ofloxacin. The accuracy of the methods was assessed by recovery studies and was found to be 98.83% and 100.12% for Cefixime Trihydrate and 102.71 % and 99.01 % Ofloxacin by using method A and B respectively. The developed method was validated with respect to linearity, accuracy (recovery), precision and specificity. The results were validated statistically as per ICH Q2 R1guideline and were found to be satisfactory. The proposed methods were successfully applied for the determination of for Cefixime Trihydrate and Ofloxacin in commercial pharmaceutical dosage form.[18] The objective of the study was to develop simple, accurate, precise and rapid UV first and second order derivative spectrophotometric methods with subsequent validation by using ICH guidelines for the determination of ofloxacin in pharmaceutical dosage form. The proposed first and second order derivative methods involve the measurement of absorbance of drug at 278 nm and 234.6 nm for the estimation of ofloxacin respectively. The linearity of the proposed methods was found in the concentration range of 0.5 – 10 µg /ml (r2= 0.9995) for first order and 2 – 10 µg /ml (r2= 0.9953) for second order derivative methods and the percentage mean recovery was found to be 100.069 % and 99.792% respectively. The methods were also statistically validated for its linearity, accuracy and precision. Both intra and inter day variation showed less percentage (%) RSD values indicating high grade of precision of these methods.[19]
Colorimetry
A colorimetric method is presented for the determination of the antibiotic ofloxacin (OFL) in aqueous solution. It is based on the use of an aptamer and gold nanoparticles (AuNPs). In the absence of OFL, the AuNPs are wrapped by the aptamer and maintain dispersed even at the high NaCl concentrations. The solution with colloidally dispersed AuNPs remains red and has an absorption peak at 520 nm. In the presence of OFL, it will bind to the aptamer which is then released from the AuNPs. Hence, AuNPs will aggregate in the salt solution, and colour gradually turns to blue, with a new absorption peak at 650 nm. This convenient and specific colorimetric assay for OFL has a linear response in the 20 to 400 nm. OFL concentration range and a 3.4 nm. detection limit. The method has a large application potential for OFL detection in environmental and biological samples.[20] An accurate and precise colorimetric method is presented for the determination of ofloxacin and cefixime in same pharmaceutical formulation. Ofloxacin forms an orange-coloured product in the presence of ferric chloride solution in acidic medium and the absorbance of orange coloured species formed was measured at 435 nm against reagent blank and Beer's law was obeyed in the concentration range of 15-75 μg/mL. While cefixime forms a greenish coloured product with Fehling solution and the absorbance of greenish coloured species formed was measured at 490 nm against reagent blank and Beer's law was obeyed in the concentration range of 5-40 μg/mL. The amount of cefixime and ofloxacin present in the sample was computed from calibration curve. It is also found that there is no interference of cefixime while estimation of ofloxacin and vice versa.[21] A simple highly sensitive spectrophotometric method was developed for the quantification of ofloxacin (RS)-7-fluoro-2-methyl-6-(4-methylpiperazin- 1-yl)-10-oxo-4-oxa-1-azatricyclo). The method involves the reaction of the target compound with copper sulphate in acetic acid in presence of sodium nitrite reagent to produce a bluish green colour chromogen. The derivative chromogen exhibits absorption maxima at 404 nm. Under this reaction, no degradation occurs. The proposed method can be utilized as a stability indicating assay. The different experimental parameters affecting the derivatization reaction was carefully studied and incorporated into the procedure. Under the described conditions the proposed method is linear over the concentration range of 5-45 mcg/ml and the coefficient of determination were >0.999 with a relative standard deviation of 0.236%. The average recovery of the target compound is 99.46% with a limit of quantification (LOQ) of 0.293mcg/ml and the limit of detection (LOD) 0.096mcg/ml. The mechanism of the derivatization reaction is proposed and advantages of the proposed method is discussed.[22] The present work was aimed to develop a spectrophotometric method in ultraviolet region for the estimation of ofloxacin in pure form and pharmaceutical formulations. Ofloxacin is an antibacterial agent and belongs to the class of fluoroquinolones used in the treatment of respiratory tract infections. Ofloxacin exhibited maximum absorbance at 291.6 nm in 0.1 N hydrochloric acid with an apparent molar absorptivity of 3.175 × 10 4. Beer's law was obeyed in the concentration range of 1-10 μg/mL. Results of the analysis were validated by recovery. [23] Ofloxacin (OFL) is an effective antibiotic against bacteria. However, the overuse of ofloxacin can lead to residues in animal-derived foods, posing a potential threat to human health. Due to the issue of false positives in single-mode detection, it is crucial to establish a multi-mode method for accurate and sensitive detection of ofloxacin. Peroxidase-like active iron-nickel bimetallic organic framework (FeNi-MOF) and orange fluorescent carbon dots (OCDs) synthesized by a simple one-pot method were used to establish a dual-mode colorimetric/radiometric fluorescence biosensor for the detection of ofloxacin residues. In colorimetric mode, in the presence of hydrogen peroxide (H2O2), FeNi-MOF can catalyse the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to produce blue oxTMB. However, the fluorescence of OCDs at 588 nm will be quenched by oxTMB, thus forming a radiometric fluorescence signal with the fluorescence of FeNi-MOF at 420 nm. The linear range of the dual-mode detection method was 10−7-10−2 mg/mL, and the detection limits were 1.1 ng/kg (colorimetric) and 0.34 ng/kg (radiometric fluorescence). In addition, the constructed smartphone sensing platform is also well applied for on-site portable detection. Therefore, we have established a dual-mode sensor with high specificity, accuracy, and excellent anti-interference ability for OFL detection, and satisfactory results are also obtained in the actual spiked samples.[24] The purpose of this study was to use solid lipid nanoparticles (SLN) to improve the pharmacological activity of ofloxacin. Ofloxacin-loaded SLN were prepared using palmitic acid as lipid matrix and poly vinyl alcohol (PVA) as emulsifier by a hot homogenization and ultrasonication method. The physicochemical characteristics of SLN were investigated by optical microscope, scanning electron microscopy, and photon correlation spectroscopy. Pharmacokinetics was studied after oral administration in mice. In vitro antibacterial activity and in vivo antibacterial efficacy of the SLN were investigated using minimal inhibitory concentrations (MIC) and a mouse protection model. The results demonstrated that the encapsulation efficiency, loading capacity, diameter, polydispersity index, and zeta potential of the nanoparticles were 41.36% ± 1.50%, 4.40% ± 0.16%, 156.33 ± 7.51 nm, 0.26 ± 0.04, and −22.70 ± 1.40 mv, respectively. The SLN showed sustained release and enhanced antibacterial activity in vitro. Pharmacokinetic results demonstrated that SLN increased the bioavailability of ofloxacin by 2.27-fold, and extended the mean residence time of the drug from 10.50 to 43.44 hours. Single oral administrations of ofloxacin-loaded nanoparticles at 3 drug doses, 5 mg/kg, 10 mg/kg, and 20 mg/kg, all produced higher survival rates of lethal infected mice compared with native ofloxacin. These results indicate that SLN might be a promising delivery system to enhance the pharmacological activity of ofloxacin.[25] One titrimetric and two spectrophotometric methods have been described for the determination of ofloxacin (OFX) in bulk drug and in tablets, employing N-Bromo succinimide as an analytical reagent. The proposed methods involve the addition of a known excess of NBS to OFX in acid medium, followed by determination of unreacted NBS. In titrimetric, the unreacted NBS is determined iodometrically, and in spectrophotometry, unreacted NBS is determined by reacting with a fixed amount of either indigo carmine (Method A) or metanil yellow (Method B). In all the methods, the amount of NBS reacted corresponds to the amount of OFX. Titrimetric allows the determination of 1-8 mg of OFX and the calculations are based on a 1:5 (OFX: NBS) reaction stoichiometry. In spectrophotometry, Beer’s law is obeyed in the concentration ranges 0.5-5.0 µg/mL for method A and 0.3-3.0 µg/mL for method B. The molar absorptivities are calculated to be 5.53x104 and 9.24x104 L/mol/cm for method A and method B, respectively. The methods developed were applied to the assay of OFX in tablets, and results compared statistically with those of a reference method. The accuracy and reliability. [26] The objective of the current study was to develop a direct, sensitive spectrophotometric method based on the oxidation of Ofloxacin using potassium permanganate in alkaline medium. The rate of change of absorbance was measured at 603 nm. The initial rate method and fixed time method (at 4 min) are utilised to construct calibration graphs for calculating the concentration of the drug. The results were validated through inter day and intraday precision assays according to the ICH guidelines and also through recovery studies. Statistical comparison of the proposed methods with that of reference method shows excellent agreement and indicates no significant difference in their accuracy and precision. [27] Kishore, Lalit; Kumar, Ashok; Nair, Anroop; Kaur Navpreet, Kinetic Spectrophotometric Method for the Estimation of Ofloxacin in Pharmaceutical Formulations, J. Mex. Chem. Soc. 2012, 56(4), 355-361
HPTLC Method
Ofloxacin and tinidazole in combination is available as tablet dosage forms in the ratio of 1:3. Stability indicating HPTLC method was developed for analysis of above formulation. Ofloxacin and tinidazole were separated on the plate coated with silica gel 60 F254 using a mixture of Dioxan: Ethyl acetate: Toluene: Acetic acid: Water (5.5:5:3:2:2 v/v) as mobile phase. Quantification was carried out by the use of densitometer in absorbance mode at 307nm. The Rf value of ofloxacin and tinidazole was found to be 0.12 and 0.85 respectively. The percent recovery was found to be 99.85% and 99.45% for ofloxacin and tinidazole respectively. This proposed method was quantitatively evaluated in terms of calibration of concentration range, stability and accuracy. It can be adopted for routine analysis of the formulation [28] To develop a simple, selective and sensitive high performance thin layer chromatographic method for the determination of Ofloxacin in human plasma. The method had been validated for linearity, precision, accuracy and stability following EMEA and US CDER guidelines for bioanalytical method validation. Sample was prepared by liquid – liquid extraction using chloroform. Chloroform layer separated was evaporated and reconstituted in methanol and spotted on TLC plates precoated with silica gel 60 F254. Mirtazapine was used as an internal standard. The mobile phase consisted of a mixture of n- butanol: ethanol: ammonia in the ratio of 5:5:4 v/v/v. The drug showed considerable absorbance at 294 nm. The method was found to be linear over the concentration range of 50-600 ng/ band. Mean drug recovery was found to be 98.76%. Ofloxacin in plasma samples was stable parameters as per EMEA and US CDER guidelines. The method was found to be precise, accurate and can further be extended to pharmacokinetic studies for therapeutic drug monitoring of Ofloxacin in routine clinical practices. [29] High Performance Thin Layer Chromatography using silica gel aluminium plate 60F254 (10*10cm) as stationary Phase and Methanol: Chloroform: Ammonia (3:5:2) as Mobile Phase. The developed plates scanned densiometrically using UV 273nm wavelength. The Rf value of Ofloxacin, Clotrimazole and Ornidazole was found to be 0.49, 0.73 and 0.89 respectively. The method was validated for different validation parameter such as linearity, accuracy, precision, LOD, LOQ and robustness and the result were found to be within the acceptance limit as per the guideline of international conference on Harmonization (ICH). [30] The objective of this work was to develop and validate simple, rapid and accurate chromatographic methods for simultaneous determination of ofloxacin and ornidazole in solid dosage form. The first method was based on reversed phase high performance liquid chromatography, on Interrail C18 column (250 mm, 4.6 i.d.), using acetonitrile: methanol: 0.025M phosphate buffer, pH 3.0 (30:10:60 % v/v/v) as the mobile phase, at a flow rate of 1 ml/min at ambient temperature. Quantification was achieved with UV detection at 318 nm over a concentration range of 2-40 µg/ml for ofloxacin and 5-100 µg/ml for ornidazole. The mean retention time of ofloxacin and ornidazole was found to be 4.04 min and 5.83 min, 6.77 min (isomers), respectively. The amount of ofloxacin and ornidazole estimated as percentage of label claimed was found to be 100.23 and 99.61%, with mean percent recoveries 100.20 and 100.93%, respectively. The second method was based on TLC separation of these drugs using silica gel 60F254 aluminium sheets and dichloromethane: methanol:25% ammonia solution (9.5:1:3 drops v/v) as mobile phase. Detection was carried out at 318 nm over the concentration range of 20-100 ng/spot for ofloxacin and 50-250 ng/spot for ornidazole. The mean Rf value of ofloxacin and ornidazole was found to be 0.16 and 0.56, 0.78 (isomers), respectively. The amount of ofloxacin and ornidazole estimated as percentage of label claimed was found to be 100.23 and 99.61% with mean percent recoveries 100.47 and 99.32%, respectively. Both these methods were found to be simple, precise, accurate, selective and rapid and could be successfully applied for the determination of pure laboratory prepared mixtures and tablets.[31] The purpose of this work was to develop a rapid and reliable HPTLC method for estimating and validating Ofloxacin and Flavoxate by applying QBD techniques. Ofloxacin is used in the treatment of pneumonia and bronchitis while flavoxate in the treatment of overactive bladder. The study utilised a Box–Behnken experimental design utilising response surface methods to examine the impact of migration distance, band length, and chromatographic chamber saturation time on Rf values. Based on the preliminary trials, the Rf values for ofloxacin and flavoxate hydrochloride were observed to be between 0.13 and 0.83 under the chromatographic conditions. The optimized chromatographic conditions included a saturation time of 10 min, a band length of 6mm, a solvent front of 80mm, and a mobile phase composed of methanol: ethyl acetate: Chloroform: Ammonia in a ratio of 3:6:1:0.1 v/v. In compliance with International Conference on Harmonization (ICH) rule Q2 (R1), the enhanced HPTLC method was validated. The study’s findings demonstrate that optimizing the HPTLC method with the number of speculative runs can be accomplished through the effective application of quality by design. For the regular analysis of ofloxacin and flavoxate hydrochloride in combination tablet formulation, the validated HPTLC method worked well. [32] A new simple High Performance Thin Layer Chromatographic (HPTLC) method for determination of Cefixime and Ofloxacin in combined tablet dosage form has been developed and validated. The mobile phase selected was Methanol: Ethyl acetate: Ammonia (3.5: 3.5:1.5 v/v/v) with UV detection at 295 nm. The retention factor for Cefixime and Ofloxacin were found to be 0.78 ± 0.10 and 0.61 ± 0.12. Results found to be linear in the concentration range of 50-500 ng/band for both Cefixime and Ofloxacin. The method has been successfully applied for the analysis of drugs in pharmaceutical formulation. The % assay (Mean ± S.D.) was found to be 99.89 % ± 0.14 for Cefixime and 102.2 % ± 0.11 for Ofloxacin. The method was validated with respect to linearity, accuracy, precision and robustness as per the International Conference on Harmonisation (ICH) guidelines. [33] Simple, precise, and accurate UV-Spectrophotometric and high-performance thin-layer chromatography (HPTLC) methods for the simultaneous determination of Nitazoxanide and Ofloxacin in pharmaceutical preparations have been developed and validated. The method was developed using aluminium plates pre-coated with silica gel 60 F254 HPTLC plates as a stationary phase with toluene: chloroform: carbon tetra chloride: toluene: glacial acetic acid solutions in the proportion of (10:5:3:0.5 v/v/v/v) as mobile phase. Densitometric quantification was performed at 241 nm. Well-resolved bands were obtained with RF values 0.36, 0.57 and 0.63 for Rosiglitazone maleate, Nitazoxanide, and Ofloxacin, respectively. Rosiglitazone maleate was used as an internal standard. The calibration curves were linear within the concentration range of 5–25 μg/ml for each drug. Two simple spectrophotometric methods have been developed for simultaneous estimation of Nitazoxanide, and Ofloxacin from tablet dosage form. The first method, simultaneous equation method, involves the measurement of absorbances at two wavelengths 221.8 nm (λmax of Nitazoxanide) and 244.3 nm (λmax of Ofloxacin), and the second method is First order derivative spectroscopy, wavelengths selected for quantitation were 263.6 nm for Nitazoxanide and 269.2 nm for Ofloxacin. The proposed method gave good validation results and the statistical analysis performed proved that the method is precise, accurate and reproducible, and hence can be employed for routine analysis of Nitazoxanide and Ofloxacin in bulk and commercial formulations. [34] A simple, rapid, and accurate high-performance thin-layer chromatography (HPTLC) method is described for the simultaneous determination of levofloxacin hemihydrate and ornidazole in tablet dosage form. The method is based on the HPTLC separation of the two drugs followed by densitometric measurements of their spots at 298 nm. The separation is carried out on Merck TLC aluminium sheets of silica gel 60 F254 using n-butanol- methanol-ammonia (5:1:1.5, v/v/v) as mobile phase. The linearity is found to be in the range of 50–250 and 100–500 ng/spot for levofloxacin hemihydrate and ornidazole, respectively. The method is successively applied to pharmaceutical formulation because no chromatographic interferences from the tablet excipients are found. The suitability of this HPTLC method for the quantitative determination of the compounds is proved by validation in accordance with the requirements laid down by International Conference on Harmonization (ICH) guidelines. [35]
Liquid Chromatography-Mass Spectrometry method
A sensitive and selective liquid chromatography–tandem mass spectrometry method was developed and validated for the determination of ofloxacin in 20 μl human plasma over the concentration range of 0.078–20 μg/ml. Sample preparation was achieved by protein precipitation with acetonitrile and methanol containing the internal standard (Gatifloxacin). Chromatographic separation was achieved on a Luna 5 μm PFP (110 A, 50 × 2 mm) column with acetonitrile and water containing 0.1% formic acid (50:50, v/v) as the mobile phase, at a flow rate of 400 μl/ml. The within-day and between-day precision determinations for ofloxacin, expressed as the percentage coefficient of variation, were lower than 7% at all test concentrations. Recovery of ofloxacin was greater than 70% [36]. A rapid, simple, and specific method based on ultra performance liquid chromatography (UPLC) with mass spectrometry detection has been developed for quantitative analysis of ofloxacin in human aqueous humour using tobramycin as internal standard (IS). Chromatographic separation was achieved on a Waters Acquit UPLC BEH C18 Shield column (150 × 2.1 mm, 1.7 μm) eluted with 95:5 water: acetonitrile (v/v) containing 0.1% formic acid and a flow rate of 0.3 mL/minute. The total analysis time was three minutes with ofloxacin eluting at 1.67 ± 0.03 minutes. The linearity of the method ranged from 0.1 to 8 μg/mL with r2 = 0.998. The method was validated according to FDA guidelines with respect to linearity, accuracy, precision, specificity, and stability. The limits of detection and quantification were 0.03 and 0.10 μg/mL, respectively. The developed method was successfully applied to the analysis of samples that have been obtained from patients.[37] A simple, fast, and responsive liquid chromatography-tandem mass spectrometry method was established and fully validated according to the United States Food and Drug Administration guidelines for the simultaneous quantitation of ofloxacin and dexamethasone in tear fluid and partially in aqueous humour and cornea. Samples were cleaned- up by single-step precipitation using methanol as an anti-solvent. Agilent SB C18 column with 4.5 min total run time was used for chromatographic separation utilizing isocratic mode. Mass spectrometry detection was carried out by a triple quadrupole tandem mass spectrometer in the multiple reaction monitoring modes utilizing a positive electrospray ionization. The developed method showed a wide analytical range (ofloxacin: 0.7812–200 ng/ml and dexamethasone: 1.875–240 ng/ml) with good linearity (r2 > 0.99) and acceptable accuracy and precision. It also showed excellent recoveries (>85% for analytes) and a negligible matrix effect. Finally, this method was successfully applied to determine the pharmacokinetic profile of clinically used eye drop solution of ofloxacin and dexamethasone in preclinical rabbit tear fluid, suggesting its suitability for therapeutic drug monitoring in clinical practices.[38] A specific, accurate, precise and sensitive validated reverse phase liquid chromatographic (RP-HPLC) method has been developed for the simultaneous estimation of Ofloxacin, Ornidazole and its isomer in bulk drug as well as tablet dosage form. Drugs were analysed on C18 column using mobile phase acetonitrile: methanol: 0.025M phosphate buffer (pH 3.0) (30:10:60 v/v/v). A flow rate was maintained at 1.0 ml/min and detection was made at 318 nm. The retention time for Ofloxacin, Ornidazole and its isomer was found to be 4.04, 5.82 and 6.77 min respectively. Proposed method was validated for accuracy, precision, linearity and range, ruggedness. Linearity of Ofloxacin and Ornidazole was in the range of 2-40 µg/ml and 5-100 µg/ml respectively. Average percentage recoveries obtained for Ofloxacin and Ornidazole were 100.20% and 100.[39] A sensitive HPLC method has been developed for determination of ofloxacin (OFL) in biological fluids. Sample preparation was performed by adding phosphate buffer (pH 7.4, 0.1m) then extraction with trichloromethane. OFL and the internal standard, sarafloxacin (SAR), were separated on a reversed-phase column with aqueous phosphate solution-acetonitrile, 80?20, as mobile phase. The fluorescence of the column effluent was monitored at λex 338 and λem 425 nm. The retention times were 2.66 and 4.24 min for OFL and SAR, respectively, and the detection and quantitation limits were 8 and 15 ng mL−1, respectively. Plots of response against ofloxacin concentration were linear in the range 8 to 2000 ng mL−1. Recovery was 92.9% for OFL.[40] In this study, the method for separation and measurement using normal phase LC/MS/MS for levofloxacin and (R)-ofloxacin, which are enantiomers that are difficult to separate by reversed phase LC, was investigated. The mobile phase is t-butyl methyl ether/ethanol/acetic acid/ethylenediamine (30: 70: 0.2: 0.2, v/v/v/v), and the column is Phenomenex Lux i-Cellulose-5 (150 × 2.0 mm i.d., 3 μm). The two substances could be separated under this condition. The calibration curves for both levofloxacin and (R)-ofloxacin showed good linearity in the range of 0.10 to 100 ng mL−1, and the lower limit of instrument detection was levofloxacin: 0.22 ng L−1, (R)-ofloxacin: 0.33 ng L−1. As a result of applying this method to the eluates extracted from a water sample with a polymer-based reversed-phase solid-phase column and ion-exchange reversed-phase mixed solid-phase column, levofloxacin 420 ng L−1 and (R)-ofloxacin 1.7 ng L−1 were detected from sewage treated water, sensitive enantio-separation. For then, a determination that can be applied to environmental water sample measurements has been made possible.[41] Rapid and accurate reverse phase high performance liquid chromatography method is described for determination of ofloxacin from the bulk drug and pharmaceutical dosage form. It was observed that Polaris C18 (15 x 4.6 mm i.d.) with 5 µ particle size column showed most favourable chromatographic pattern over the other columns. The mobile phase consisted of buffer and acetonitrile (80:20 % v/v). The buffer was mixtures of 0.01 M ammonium acetate adjusted the pH 3 with ortho-phosphoric acid. The detection was carried out at wavelength 294 nm. The method was validated for system suitability, linearity, accuracy, precision, robustness and stability of sample solution with the linear range 10-30 µg/ ml. The method has been successfully used to assay of pharmaceutical dosage form i.e. tablets with good recoveries.[42] A simple, rapid and precise reverse phase liquid chromatographic (RP-HPLC) method was developed and subsequently validated for simultaneous estimation of Cefpodoxime proxetil and Ofloxacin in combined fixed dose oral formulation. The analysis was carried out using X-terra C8 (4.6 x 250mm, 5µm, Make: ACE), pre-packed column. The separation was carried out using a mobile phase containing a 0.25%v/v triethyl amine buffer of pH 3.5 and acetonitrile (30:70 v/v), was pumped at a flow rate of 1.2 ml/min with UV-detector and PDA detection at 227 nm. Both the drugs were well resolved on the stationary phase and the retention times were around 2.747 minute for Cefpodoxime proxetil and 2.076 minute for Ofloxacin. The method was validated and shown to be linear for Cefpodoxime proxetil and Ofloxacin. The correlation coefficients for Cefpodoxime proxetil and Ofloxacin are 0.998 and 0.999 respectively. The relative standard deviations for five replicate measurements in two sets of each drug in the tablets is always less than 2% and mean % error of active recovery not more than ±1.5%. The method was validated for precision and accuracy. The developed method could be applied for routine analysis of Cefpodoxime proxetil and Ofloxacin in tablet dosage form without any interference of excipients.[43]
Electroflorosis
A simple, rapid, and accurate high-performance thin-layer chromatography (HPTLC) method is described for the simultaneous determination of levofloxacin hemihydrate and ornidazole in tablet dosage form. The method is based on the HPTLC separation of the two drugs followed by densitometric measurements of their spots at 298 nm. The separation is carried out on Merck TLC aluminium sheets of silica gel 60 F254 using n-butanol- methanol-ammonia (5:1:1.5, v/v/v) as mobile phase. The linearity is found to be in the range of 50–250 and 100–500 ng/spot for levofloxacin hemihydrate and ornidazole, respectively. The method is successively applied to pharmaceutical formulation because no chromatographic interferences from the tablet excipients are found. The suitability of this HPTLC method for the quantitative determination of the compounds is proved by validation in accordance with the requirements laid down by International Conference on Harmonization (ICH) guidelines.[44] Capillary electrophoretic method for the separation of the enantiomers of ofloxacin using carboxymethyl?β?cyclodextrin (CM?β?CD) as chiral selector is described. The effect of the type of cyclodextrin and its concentration, buffer concentration, and its pH, as well as instrumental parameters, such as applied voltage and temperature were systematically studied. The highest resolution of ofloxacin enantiomers obtained was around 2.8. This was achieved using Tris?citrate buffer (pH 4.5) that contained 3 mg mL CM?β?CD and using UV detection (254 nm), applied voltage (12 kV), and capillary temperature of 25°C. Acceptable validation criteria for selectivity, precision, linearity, limit of detection, and quantitation were also included. Recoveries between 98.3–103.4% were obtained when the method was used to determine the enantiomers of ofloxacin that were spiked to placebos. The proposed method is fast, sensitive, inexpensive, and its usefulness was demonstrated for the analysis of five pharmaceutical preparations, two of which just contained the S?ofloxacin while the other three contained both isomers as racemic mixtures. [45] A novel and sensitive method for the simultaneous determination of enoxacin and ofloxacin has been established using capillary electrophoresis (CE) coupled with electrochemiluminescence (ECL) detection based on the ECL enhancement of tri(2,2-bipyridyl) ruthenium (II). The conditions for sample solvent type, CE separation and ECL detection were investigated systematically. The analytes were well separated and detected within 7 min. The limits of detection (S/N = 3) of enoxacin and ofloxacin are 9.0 × 10−9 and 1.6 × 10−8 mol/L, respectively. The precisions (RSD%) of intraday and interday are less than 2.1 and 4.0%, respectively. The limits of quantitation (S/N = 10) of enoxacin and ofloxacin are 3.2 × 10−7 and 5.4 × 10−7 mol/L in human urine samples and 4.1 × 10−7 and 6.9 × 10−7 mol/L in human serum samples, respectively. The recoveries of enoxacin and ofloxacin at different concentration levels in human urine, serum and eye drop samples are between 94.0 and 106.7%. The proposed method was successfully applied to the determination of the enoxacin and ofloxacin in human urine, serum and eye drop samples and the monitoring of pharmacokinetics of ofloxacin in human body.[46] We have developed a precise and accurate method for the determination of ciprofloxacin and ofloxacin in meat tissues. Our method utilizes capillary electrophoresis with a transient pseudo-isotachophoresis mechanism and liquid–liquid extraction during sample preparation. For our experiment, a meat tissue sample was homogenized in pH 7.00 phosphate buffer at a ratio of 1:10 (tissue mass: buffer volume; g/mL). The extraction of each sample was carried out twice for 15 min with 600 µL of a mixture of dichloromethane and acetonitrile at a 2:1 volume ratio. We then conducted the electrophoretic separation at a voltage of 16 kV and a temperature of 25 °C using a background electrolyte of 0.1 mol/L phosphate–borate (pH 8.40). We used the UV detection at 288 nm. The experimentally determined LOQs for ciprofloxacin and ofloxacin were 0.27 ppm (0.8 nmol/g tissue) and 0.11 ppm (0.3 nmol/g tissue), respectively. The calibration curves exhibited linearity over the tested concentration range of 2 to 10 nmol/g tissue for both analytes. The relative standard deviation of the determination did not exceed 15%, and the recovery was in the range of 85–115%. We used the method to analyse various meat tissues for their ciprofloxacin and ofloxacin contents.[47] A simple, fast, and accurate capillary zone electrophoresis method has been developed for the determination of ciprofloxacin and ofloxacin. This method uses liquid–liquid extraction. Therefore, it is characterized by a very simple procedure of sample preparation but at the same time satisfactory precision and accuracy. The extraction process of the same urine sample was repeated three times. The extraction protocol was performed each time for 15 min with 1 mL of dichloromethane and chloroform mixture in a 3:1 volume ratio. A 0.1 mol/L phosphate-borate buffer (pH 8.40) was selected as the background electrolyte. UV detection was performed at 288 nm. The separation was carried out at a voltage of 16 kV, at a temperature of 25 °C. Experimentally evaluated LOQ values for ciprofloxacin and ofloxacin were 0.2 nmol/mL urine and 0.05 nmol/mL urine, respectively. For both analytes the calibration curves exhibited linearity over the entire tested concentration range of 1–6 nmol/mL urine. The precision of the method did not exceed 15%, and the recovery was in the range of 85–115%. The developed and validated procedure was applied to analyze human urine for the content of ciprofloxacin and ofloxacin.[48] A simple, rapid and validated capillary electrophoretic method has been developed for the separation and determination of ofloxacin and ornidazole in pharmaceutical formulations with detection at 230 nm. Optimal conditions for the quantitative separations were investigated. Analysis times shorter than 4 min were obtained using a background electrolyte solution consisting of 25 mmol/L phosphoric acid adjusted with 1 m Tris’s buffer to pH 8.5, with hydrodynamic injection of 5 s and 20 kV separation voltage. The validation criteria for accuracy, precision, linearity and limits of detection and quantitation were examined and discussed. An excellent linearity was obtained in concentration range 25–250 µg/mL. The detection limits for ofloxacin and ornidazole were 1.03 ± 0.11 and 1.80 ± 0.06 µg/mL, respectively. The proposed method has been applied for the analysis of ofloxacin and ornidazole both individually and in a combined dosage tablet formulation. The proposed validated method showed recoveries between 96.16 and 105.23% of the nominal contents.[49] An alternative capillary zone electrophoresis (CZE) method for the determination of ciprofloxacin (CPFLX), gatifloxacin (GTFLX), moxifloxacin (MFLX) and ofloxacin (OFLX) through a simple aqueous electrolyte system consisting of 25 mmol L-1 of TRIS/ hydrochloride and 15 mmol L-1 of sodium tetraborate buffer mixture (pH 8.87) using direct UV detection at 282 nm within 3 min was validated. The analytical parameters of validation evaluated were: linearity (r > 0.998), selectivity (comparison between slope of the calibration curve of external standard and calibration curve of standard addition), repeatability in area for sample (RSD%: < 3.94% for CPFLX, < 3.87% for GTFLX, 1.30% for MFLX and < 1.88% for OFLX), intermediate precision in area for sample (RSD%: < 3.59% for CPFLX, < 3.09% for GTFLX, 2.67% for MFLX and < 2.25% for OFLX), accuracy (mean of recovery range: 101.2% for CPFLX, 101.0% for GTFLX, 101.3% for MFLX and 99.9% for OFLX), limit of detection (mg L-1: 2.72 for CPFLX, 1.92 for GTFLX, 0.795 for MFLX and 1.05 for OFLX), limit of quantification (mg L-1: 9.06 for CPFLX, 6.40 for GTFLX, 2.65 for MFLX and 3.50 for OFLX) and robustness. Due to its simplicity, selectivity, precision, accuracy and rapidity, the methodology can be an interesting alternative for quality assurance in the pharmaceutical industry of these drugs. [50]. Application of electromembrane extraction coupled with capillary electrophoresis was studied for ofloxacin extraction from plasma samples. Ofloxacin migrated from acidic plasma samples through a thin layer of 1-octanol immobilized in the pores of a porous hollow fiber wall into a 10 µL acidic aqueous acceptor solution located inside the lumen of the fiber. Under optimum conditions influencing electromigration (i.e., 20 min of the operation time, stirring speed of 750 rpm, donor phase pH at 4.0, acceptor pH at 3.0, and applied voltage of 30 V across the supported liquid membrane), ofloxacin was extracted from plasma samples with an enrichment factor of 100-fold corresponding to extraction percent of 24%. The calibration curve showed acceptable linearity in the range of 0.2-7.0 µg. mL-1 (R=0.9993). The limits of detection and quantification of 0.05 and 0.2 µg. mL-1 were obtained, respectively. The inter- and intra-day precision and accuracy were obtained below 8.65%. The validated method was successfully processed for the ofloxacin determination in the plasma samples of patients under ofloxacin therapy. There were no interfering peaks which indicates the great selectivity of the developed method.[51] This work is dedicated to the greenness estimation of three proposed spectrophotometric techniques [e.g., ratio difference (RD), mean centering of ratio spectra (MCR) and continuous wavelet transform of ratio spectra (CWT)] for the determination of a binary combination named Ofloxacin (OFL) and Ornidazole (ORN). Applying the green analytical chemistry methods to assess the proposed methods has widely attained the analytical community care. The greenness assessment was performed via three evaluation approaches; the “Analytical Eco-Scale”, the “National Environmental Method Index” (NEMI) and “Green Analytical Procedure Index” (GAPI). Following the examination of the zero spectrum of OFL and ORN, it is observed that OFL and ORN spectra are overlapped, so they can be detected by the methods mentioned previously. The ratio difference method was carried out at wavelengths of 294.6 nm and 265.6 nm for OFL, 292 nm and 315 nm for ORN. The linear range was (2–15 µg/mL) for OFL and (3–30 µg/mL) for ORN. The MCR method based on the use of mean centered ratio spectra in dual steps and calculating the second ratio spectra mean centered values at 294.6 nm for OFL and 315 nm for ORN. The continuous wavelet transformation which carried out using MATLAB at wavelengths of 265 nm for OFL and 306 for ORN. These techniques were intended for the binary mixture analysis in bulk powder and pharmaceutical formulations with high recoveries. The developed methods were validated according to ICH guidelines. All techniques were statistically compared to either an official method for OFL or a reported method for ORN and the results indicate that there were not any significant differences. [52]
Supercritical Fluid Extraction
Supercritical fluid extraction (SFE) of the fluoroquinolones norfloxacin and ofloxacin from chicken breast muscles was examined. A liquid chromatography with fluorescence detection was used for the determination of the fluoroquinolones. Extraction conditions of the SFE were optimized by determining the extraction parameters to achieve a sufficiently high recovery of each fluoroquinolone in fortified-muscle samples. Recovery values for the extraction of the fluoroquinolones using the SFE ranged from 70 to 87%. Chickens were treated orally with each fluoroquinolone and their muscles were extracted at set time intervals for time-course determination of the fluoroquinolones in chickens. The SFE combined with liquid chromatographic analysis showed that the concentrations of the fluoroquinolones decreased gradually with time in the chicken muscles after oral treatment, giving a concentration less than 5 ng/ml in 120 h. No further sample cleanup procedures were required after the SFE. These results suggest that SFE method is an extraction method for the determination of norfloxacin and ofloxacin in chicken muscle.[53] A supercritical fluid extraction method combined with high-performance liquid chromatography-fluorescence detection was developed for the determination of enrofloxacin, danofloxacin, and ciprofloxacin in pig muscle, lung, and kidney samples. The optimal SFE conditions were 80 degrees C, 300 kg/cm (2), 30% methanol for 40 min as a dynamic extraction time, in addition to 0.2g Na (4) EDTA and 7.0 g sea sand in the extraction vessel. The use of Na (4) EDTA and sea sand on SFE extraction resulted in improvement of the recoveries of ciprofloxacin, a polar and hydrophilic compound, as well as enrofloxacin and danofloxacin. Overall, the recoveries ranged from 86.7 to 113.1% using the Na (4) EDTA/sea sand-assisted SFE extraction method. The Na (4) EDTA/sea sand-assisted SFE-HPLC-FLD validated method was successfully carried out in pig tissues, and proved to be specific, sensitive, reliable, and accurate. The method was also applied satisfactorily for accurate quantitative residue analysis in incurred pig tissues.[54] Due to the importance of supercritical fluid technology (SFT) in different industries, it has been the subject of intense research in recent decades. Solubility is a key concept in SFT. In fact, obtaining knowledge about the theoretical concepts of solubility and related experimental measurement methods can be useful in developing and improving the quality of research in this field. This study reviews the fundamental knowledge of solubility in supercritical fluids and investigates the significant topics in this field, including high-pressure phase behaviour, experimental measurement methods, modeling, and molecular simulation of solubility.[55] An ideal extraction method should be swift, yield quantitative recovery without degradation, and the extracts should be easily separated from the solvent. The development and application of alternative green technology to replace conventional extraction methods with improved extraction efficiency and low environmental impact for the determination of natural bioactive compounds is therefore, highly important. Supercritical fluid technology offers features that overcome many limitations of conventional extraction methods. This review presents an analytical overview regarding the application of supercritical fluids in the extraction of bioactive compounds and their operative extraction conditions, along with the investigation of further improvements on the extraction efficiency and the applied techniques for the structural characterization and identification of such bioactive compounds.[56]
Fluorimetry
this is a collective data for ofloxacin from previously published methods either in alone or together with ornidazole, cefixime or dexamethasone. Many spectroscopic methods like derivative techniques, chromogenic techniques were used for newly developed additionally as improved chromatographic methods were reported for biological fluids and pharmaceutical formulations. But these two techniques few LC-MS/MS and HPTLC methods also available. Now during this present analytical research world quality on purpose or design by expert technique is employed to induce improved method for method validation. This concise review work can guide an analyst to decide on most appropriate method for a best analytical method development and validation of ofloxacin alone or together with ornidazole, cefixime or dexamethasone. [57] The coexistence of heavy metals and antibiotics is common in the environment, and their interactions may mutually alter their environmental behaviours and risks. This study investigated ofloxacin (OFL)–Cu (II) interaction using fluorescence quenching experiments. The possible artifacts were excluded and OFL quenching was attributed to static quenching as suggested by the linear Stern–Volmer plot and decreased quenching with increased temperature. The OFL–Cu (II) interaction was quantitatively described using a stoichiometry equation. The calculation suggested that OFL–Cu (II) association was the mixture of 1:1 and 1:2 complexes. The negative ΔG values and the negative ΔH values suggested that the complexation is a spontaneous and exothermic process. Cation-π binding and electrostatic interaction were excluded and the complexation of Cu (II) with OFL ketonic and carboxyl groups was proposed through UV–visible spectrum characterization, pH dependent complexation, and thermodynamic analysis. [58] This paper reports the assay of ofloxacin by fluorescence spectrophotometry. The fluorescence strength of ofloxacin is proportional to its concentration within the range from 0.500-25.0 ppm. The linear regression coefficient equals to 0.9999, and the recovery ratio is 99.0%. The results of determination for the samples of ofloxacin capsule from China and Japan are very close to that determined by the ultraviolet spectrophotometry, there isn't any obviously difference which was examined by Student's test. This method is both simplicity and accuracy, also it needs only one kind of reagent. It's believable that this method would be suitable for the use in clinical medicine and pharmaceutical industry.[59] The present method reports a rapid, inexpensive and sensitive sensing system based on fluorescence turn-on strategy for trace detection of ciprofloxacin (CIP) and ofloxacin (OFL) in aqueous samples. In a one pot method, copper nanocluster whose dimensions are less than 15 nm, were easily prepared and decorated with sodium gluconate (Gl@CuNCs) as a biocompatible material. The Gl@CuNCs were characterized with XRD, TEM, DLS, TG-DTA techniques as well UV–Vis, FT-IR and fluorescence spectroscopies. The maximum fluorescence emission of Gl@CuNCs at 414 nm with excitation at 322 nm shifted to higher wavelength upon addition of CIP and OFL. A good linear relationship between fluorescence emission and drug concentration was achieved in the concentration range of 0.005–0.3 μg mL−1 (15–900 nM for CIP and 14–830 nM for OFL). The limits of detection (LOD) for the determinations of CIP and OFL were calculated to be 9 and 8 nM, respectively. Furthermore, even a 100-fold higher concentration of interfering species had no significant effect on the detection of CIP and OFL. The proposed method was successfully used to determine CIP and OFL in drinking water, cow milk, human urine and serum samples with satisfactory recoveries. [60] Ofloxacin (OFL) and its (S)-enantiomer, levofloxacin (LEV), are among members of the fluoroquinolone antibiotic class, renowned for their broad-spectrum efficacy against both gram-negative and gram-positive bacteria. These potent drugs have been widely used in both human and veterinary medicine, working as bactericidal agents by binding to DNA gyrase, an essential enzyme for bacterial DNA replication. Understanding the binding constants of these drugs to DNA is vital for elucidating their interaction mechanisms and enhancing our grasp of gene expression regulation. The interactions of LEV and OFL with calf thymus DNA under a physiological medium (0.02 M tris-HCl buffer, pH 7.4) using UV spectrophotometry and spectrofluorimetric were investigated. The assay results obtained by applying two spectroscopic approaches confirmed the presence of the interaction of LEV and OFL antibiotics with DNA. In the LEV-DNA and OFL-DNA interactions, hyperchromic effect and fluorescence quenching were observed for UV spectrophotometric and spectrofluorometric measurements, respectively. In the spectrophotometric analysis, the binding constants for the LEV-DNA and OFL-DNA complexes at 298 K were determined as (1.24 ± 0.047) x 103 and (1.39 ± 0.040) x 103 M− 1, respectively. In the spectrofluorimetric analysis of the interaction of LEV and OFL with DNA, the thermodynamic properties were examined at three distinct temperatures. Based on the fluorescence signal changes the binding constants at 293, 298, and 310 K were calculated as (8.91 ± 0.161) x 103, (7.62 ± 0.098) x 103, and (6.08 ± 0.041) x 103 M− 1 for LEV-DNA and, (3.14 ± 0.053) x 103, (3.04 ± 0.031) x 103, and (2.78 ± 0.023) x 103 M− 1 for OFL-DNA, respectively. In these assays, the Gibbs free energy (ΔG0), entropy (ΔS0), and enthalpy (ΔH0) were determined using the Van’t Hoff equation. The negative ΔG? values indicate that both LEV-DNA and OFL-DNA interactions are spontaneous. Furthermore, the positive ΔS? and negative ΔH? values revealed that electrostatic forces played a significant role in the binding LEV and OFL to DNA. [61] Two rare- earth complexes with a high fluorescence activity, namely Terbium (Tb)-Ofloxacin (OFLX)-Phenanthroline (Phen) and Europium (Eu)-OFLX-Phen, were prepared. The coordination forms, structure characteristics, and fluorescence properties of the prepared complexes were studied by powder diffraction, infrared spectroscopy, elemental and thermogravimetric analyses. The results show that Tb (OFLX)3Phen and Eu (OFLX)3Phen complexes were successfully prepared. The infrared (IR) spectroscopy showed that the ligand of ofloxacin could coordinate with rare-earth Tb (?) or (?) ligands via single and double coordination’s. The fluorescence spectra showed that complexes exhibited distinct fluorescence characteristic peaks, which differed from those of ligands. The optimum excitation and emission wavelengths of Tb (OFLX)3 Phen complex were 275 and 545nm, respectively, while those of Eu (OFLX)3Phen were 325 and 614 nm. The fluorescence spectrum revealed that the complex can be used as a fluorescent probe to detect the drug presence. Moreover, the photoluminescence (PL) and electroluminescence (EL) properties of the complexes were studied. The rare-earth complexes formed in this experiment are instrumental in further fluorescent probe applications. [62] In this study, first, second, third, and fourth-order derivative spectrophotometric methods utilizing the peak—zero (P—O) and peak-peak (P—P) techniques of measurement were developed for the determination of levofloxacin, norfloxacin, and moxifloxacin. These methods were applied to their combined pharmaceutical dosage form or individually for levofloxacin, norfloxacin, and moxifloxacin [63]
Voltammetry
The fluoroquinolone antibacterial agent ofloxacin was studied by adsorptive stripping voltammetry. Controlled interfacial accumulation of ofloxacin on a static mercury drop electrode in the hanging mercury drop mode provides high sensitivity. The linear concentration range was 0.079–197.5 μg ml−1 when using a 60-s preconcentration at −1 V vs. Ag/AgCl in Britton-Robinson buffer of pH 6.00. The detection limit of ofloxacin was 1 ng ml−1. The precision is excellent with a relative standard deviation of ca. 0.75% at a concentration of 0.848 μg ml−1.[64] This work is dedicated to the greenness estimation of three proposed spectrophotometric techniques [e.g., ratio difference (RD), mean centering of ratio spectra (MCR) and continuous wavelet transform of ratio spectra (CWT)] for the determination of a binary combination named Ofloxacin (OFL) and Ornidazole (ORN). Applying the green analytical chemistry methods to assess the proposed methods has widely attained the analytical community care. The greenness assessment was performed via three evaluation approaches; the “Analytical Eco-Scale”, the “National Environmental Method Index” (NEMI) and “Green Analytical Procedure Index” (GAPI). Following the examination of the zero spectrum of OFL and ORN, it is observed that OFL and ORN spectra are overlapped, so they can be detected by the methods mentioned previously. The ratio difference method was carried out at wavelengths of 294.6 nm and 265.6 nm for OFL, 292 nm and 315 nm for ORN. The linear range was (2–15 µg/mL) for OFL and (3–30 µg/mL) for ORN. The MCR method based on the use of mean centered ratio spectra in dual steps and calculating the second ratio spectra mean centered values at 294.6 nm for OFL and 315 nm for ORN. The continuous wavelet transformation which carried out using MATLAB at wavelengths of 265 nm for OFL and 306 for ORN. These techniques were intended for the binary mixture analysis in bulk powder and pharmaceutical formulations with high recoveries. The developed methods were validated according to ICH guidelines. All techniques were statistically compared to either an official method for OFL or a reported method for ORN and the results indicate that there were not any significant differences. [65] A multi-wall carbon nanotubes (MWNTs)-Nafion film-coated glassy carbon electrode (GCE) was fabricated and the electrochemical behaviour of ofloxacin on the MWNTs-Nafion film-coated GCE were investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The oxidation peak current of ofloxacin increased significantly on the MWNTs-Nafion film modified GCE compared with that using a bare GCE. This nano-structured film electrode exhibited excellent enhancement effects on the electrochemical oxidation of ofloxacin. A well-defined oxidation peak attributed to ofloxacin was observed at 0.97 V and was applied to the determination of ofloxacin. The oxidation peak current was proportional to ofloxacin concentration in the ranges 1.0 × 10−8 to 1.0 × 10−6 mol/L and 1.0 × 10−6 to 2.0 × 10−5 mol/L. A detection limit of 8.0 × 10−9 mol/L was obtained for 400 s accumulation at open circuit (S/N = 3). This method for the detection of ofloxacin in human urine was satisfactory. [66]. A novel electrochemical sensor is described for the determination of ofloxacin (OFL) in environmental water samples. A laser-modified glassy carbon electrode (LGCE) was structured and characterized by scanning electron microscopy, atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. The increase in electrochemical activity is due to a moderate increase in the surface roughness and to the presence of functional groups on the LGCE. Under optimal conditions (viz. a pH value of 5.5, a laser power of 1.8 W and an action time of 40 s), the sensor is capable of detecting OFL by differential pulse voltammetry at a working potential of +0.91 V (versus Ag/AgCl). Response is linear from 0.25 to 200 μM for OFL concentration range, and the detection limit is 75 nM (at S/N = 3). Removal of oxygen from samples is not required. The sensor was successfully applied to the determination of OFL in spiked groundwater, tap water and wastewater samples, with apparent recoveries from 94.0 to 108.0% and a relative standard deviation of less than 4.8%.” [67] Excessive use of ofloxacin (OFL) leaves residues in animal-derived foods and surrounding environment. Therefore, it is urgent to develop efficient technique for trace OFL detection. Herein, a highly stable and robust voltametric sensor was fabricated for trace OFL determination coupling molecularly imprinting film with AuNP and UiO-66 MOF dual-encapsulated black phosphorus nanosheets (MIP/AuNP/UiO-66@BPNS). UiO-66 MOFs were grown in-situ on the BPNS surface using Zr4+ adsorbed on BPNS surface as nucleation sites, and then AuNPs were electrodeposited to further encapsulate BPNS through chelation interaction. Subsequently, MIP films were electropolymerized onto the surface of AuNP/UiO-66@BPNS in the presence of OFL and pyrrole. AuNP and UiO-66 MOF dual-encapsulated BPNSs not only effectively improved BPNS stability, but produced a large surface area to accommodate more imprinting sites. The MIP/AuNP/UiO-66@BPNS modified glassy carbon electrode (GCE) exhibited extraordinary sensing performance toward OFL oxidation over a broad concentration range (0.001 − 5 μM) with ultrahigh sensitivity (377.24 μA μM−1) and extremely low detection limit (0.15 nM). Moreover, the MIP/AuNP/UiO-66@BPNS/GCE demonstrated stable voltammetric response for two months, strong discriminability against potential interfering species, and highly consistent sensitivities even in various complex matrices. The MIP/AuNP/UiO-66@BPNS/GCE achieved accurate determination of OFL in milk, serum and livestock wastewater with satisfactory recovery.[68] The highly sensitive determination of ofloxacin (OFL) in human serum and urine was achieved on a novel tryptophan-graphene oxide-carbon nanotube (Trp-GO-CNT) composite modified glassy carbon electrode (Trp-GO-CNT/GCE). The Trp-GO-CNT composite was fabricated, and its morphologies and surface functional groups were characterized by field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared (FT-IR) spectroscopy. The electrochemical properties of Trp-GO-CNT/GCE were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The superior electrochemical behaviours of Trp-GO-CNT/GCE toward OFL can be mainly assigned to the excellent electrocatalytic activity of Trp, the great conductivity and high surface area of GO and CNT, and the synergistic effect between Trp, GO and CNT. Under optimum conditions, a wide and valuable linear range (0.01–100?μM), a low detection limit (0.001?μM, S/N=3), a good linear relationship (R2>0.999), good stability and repeatability were obtained for the quantitative determination of OFL. Furthermore, the Trp-GO-CNT electrochemical sensor was successfully applied to the determination of OFL in human serum and urine samples, and satisfactory accuracy and recovery could be obtained. [69] A new electrode was prepared based on functionalized graphene and gold nanoparticles dispersed in a chitosan film. Such an electrochemical sensor determines ofloxacin in the presence of dopamine, paracetamol, and caffeine. Characterization (morphological and electrochemical) was done using scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. The sensor design improved the analytical signal, the electrochemical activity, and the electron transfer rate. Ofloxacin was determined by square-wave voltammetry, with a linear concentration range of 0.10–4.9 μmol L−1 (r = 0.999, LOD = 12 nmol L−1). The proposed sensor showed good repeatability and selectivity and was applied successfully to the determination of ofloxacin in pharmaceutical formulations, synthetic urine, and water river samples. The proposed method proved to be excellent; therefore, it is an alternative method for the determination of ofloxacin.[70] The electrochemical behaviour of antibiotic drug (ofloxacin), at carbon paste electrode CPE, is thoroughly investigated. Chemical and electrical parameters affecting the adsorptive voltammetric measurements are optimized. Deferential pulse DP is swept over potential range from-1000 to +400mV in the presence of Britton-Robeson buffer pH 7, with accumulation time 30s, scan rate 50mV/s and pulse amplitude 50mV. The responses are linear over the concentration range 1.65-23.1ïÂÂg/ml with correlation coefficient .0.998while the limit of detection is 0.17ïÂÂg/ml. The method has been applied successfully for the determination of active ingredient in the Egyptian pharmaceutical products and in spiked urine with mean recoveries of 100.025±2.33, and 98±2.38 respectively.[71] A simple physical method was developed for the surface modification and the solubilization of MWNTs in water by Congo red. The resulting water-soluble MWNTs (MWNTs-CR) can form stable and uniform films on solid supports when dried, which was used to fabricate MWNTs-CR modified glassy carbon electrodes (MWNTs-CR/GCE). Voltammetric studies showed that MWNTs-CR/GCE exhibited a strong enhancement effect on the electrooxidation of ofloxacin. MWNTs-CR films were also proved to possess overwhelming advantages as electrochemical sensing films over other commonly used MWNTs composite films (e.g., MWNTs-DHP and MWNTs-Nafion), reflected by the higher oxidation current, lower background and stronger accumulation capacity towards less soluble species. The sensitive oxidation of ofloxacin at MWNTs-CR/GCE was used for the determination of ofloxacin. Under optimal conditions, the oxidation current was proportional to ofloxacin concentration in the ranges of 5×10−8–3.0×10−5?M. The detection limit of 9×10−9?M was obtained for 350?s accumulation at open circuit (S/N=3). This method was applied to the determination of ofloxacin in human urine and the result was satisfying.[72] The polarographic and voltammetric behaviour of ofloxacin was studied by various electrochemical methods. A well-defined linear-sweep voltammetric peak was obtained at -1.343 V (vs. saturated calomel elctrode) in Britton-Robinson buffer (pH 4.00). The characteristics of the peak have been examined in detail. The experimental results prove that the reduction of ofloxacin is irreversible and that the peak has adsorption characteristics. A mechanism is proposed for the reduction of the sample. The peak current (i'p) is proportional to the concentration over the range 8 × 10−4−2 × 10−5 mol 1−1 and the limit of detection is 4 × 10−6 mol 1−1. A single-sweep oscillopolarographic method was developed for the determination of ofloxacin in pharmaceutical formulations. The mean recovery of ofloxacin was 101.0% with an relative standard deviation of 2.2%.[73] Adsorption phenomena of ofloxacin at hanging mercury drop electrode (HMDE) in Britton-Robinson buffer solution with pH of 8.36 were studied by means of square-wave voltammetry (SWV). The SWV response of ofloxacin is sensitive to pH, type of the supporting electrolyte, the ofloxacin concentration, the accuI11lllation time and po-tential, as well as the exciting signal parameters such as frequency, amplitude and potential increment. The optimization of experimental conditions for quantitative determination of ofloxacin was achieved. A square-wave voltammetric method for quantitative determination of ofloxacin is developed. The detection limit of 4'10-8 mol ofloxacin was found.[74] A simple, sensitive and highly selective electrochemical method was developed for the simultaneous determination of nitazoxanide and ofloxacin in aqueous media (Britton-Robinson buffer, pH-8.36) on a hanging mercury drop electrode (HMDE) using differential pulse polarography (DPP). Using DPP a separation of about 936 mV between the peak oxidation potentials of nitazoxanide and ofloxacin present in binary mixtures was obtained. The quantification limits for the simultaneous determination of nitazoxanide and ofloxacin were 0.083 μg/ml and 0.208 μg/ml, respectively. The proposed method was successfully applied for the simultaneous determination of nitazoxanide and ofloxacin in bulk drug and pharmaceutical tablet formulation.[75] This paper examined use of a boron doped diamond electrode (BDDE) for the electroanalysis of ofloxacin (one of the fluoroquinolone compounds) by cyclic voltammetry (CV) and square wave voltammetry (SWV) in the presence of anionic surfactant (sodium dodecyl sulfate, SDS). The current signal due to the oxidation process was a function of the amount of ofloxacin, pH of the medium, effect of SDS and scan rate. Cyclic voltammetric studies indicated an irreversible behaviour of ofloxacin in phosphate buffer solution at pH 2.0 with well-defined oxidation peak at +1.24 V (absence SDS) and +1.21 V (presence of SDS) vs. Ag/AgCl, respectively. With optimized experimental parameters, the current response of ofloxacin was proportionally linear in the concentration range from 1.0×10-7 to 3.5×10-6 M. A detection limit of 1.76×10-8 M was observed anodically electrochemical surface pretreatments. The practical applicability of the developed method was demonstrated on the determination of ofloxacin in human urine and pharmaceutical samples. In this way, BDD electrode may represent an efficient alternative to widely used modified electrodes in the determination of fluoroquinolone compounds.[76]
Gas Chromatography Maa Spectrometry (GCMS)
A widely applicable original GC-MS/MS method was explored to measure the enrofloxacin and ofloxacin residues in chicken tissues and pork qualitatively and quantitatively. The experimental samples were processed on the basis of LLE-SPE. Trimethylsilyl diazomethane (TMSD) was chosen to react derivatively with enrofloxacin and ofloxacin. The recoveries of enrofloxacin and ofloxacin in fortified blank samples were 78.25% ~ 90.56% and 78.43% ~ 91.86% severally. The LODs were 0.7 ~ 1.0 μg/kg and 0.1 ~ 0.2 μg/kg, respectively. The LOQs were 1.6 ~ 1.9 μg/kg and 0.3 ~ 0.4 μg/kg, respectively. It is verified that various experimental data fills the bill of the FAO & WHO (2014) for veterinary drug residue detection. Real samples obtained from local markets underwent analysis using the established method, revealing no detectable residues of enrofloxacin and ofloxacin in any samples. [77] The analysis of drugs in various biological fluids is an important criterion for the determination of the physiological performance of a drug. After sampling of the biological fluid, the next step in the analytical process is sample preparation. Sample preparation is essential for isolation of desired components from complex biological matrices and greatly influences their reliable and accurate determination. The complexity of biological fluids adds to the challenge of direct determination of the drug by chromatographic analysis, therefore demanding a sample preparation step that is often time consuming, tedious and frequently overlooked. However, direct online injection methods offer the advantage of reducing sample preparation steps and enabling effective pre-concentration and clean-up of biological fluids. These procedures can be automated and therefore reduce the requirements for handling potentially infectious biomaterial, improve reproducibility, and minimize sample manipulations and potential contamination. This review is focused on the discovery and development of high-performance liquid chromatography (HPLC) and gas chromatography (GC) with different detectors. The drugs covered in this review are antiepileptics, antidepressant (AD), and quinolones. The application of these methods for determination of these drugs in biological, environmental and pharmaceutical samples has also been discussed.[78] In this study, heterogeneous Fenton-like degradation of ofloxacin (OFX) was investigated by sludge derived carbon (SC). The effects of SC catalyst, temperature and pH on the efficiency of ofloxacin degradation were investigated. SC treated with sulfuric acid (SC-H2SO4) performed high catalytic activity, indicating that sulfate group produced low pH of the surface and was beneficial for heterogeneous Fenton-like degradation. The removal of ofloxacin and TOC was 91.5% and 62.3%, respectively, after 180?min adsorption and 540?min oxidation, at pH?6 and a dosage of 138?mg?L−1 H2O2. It was found that OFX conversion increased with the decrease of pH and OFX was degraded under the wide range of pH (3–6) by SC-H2SO4. These promising results clearly demonstrate the potential of the heterogeneous Fenton-like process for the effective degradation of ofloxacin by SC-H2SO4. Based on intermediated products identified by gas chromatography–mass spectrometry, a possible OFX oxidation pathway in Fenton-like reaction was proposed.[79] The main purpose of this research work is to investigate and compare the antimicrobial properties of Chrysophyllum albidum seed and stem bark essential oils, against some selected pathogenic isolates, to compare the phytochemical composition of the oil of Chrysophyllum albidum seeds and stem bark, to analyse the chemical compounds responsible for activities of the essential oil using Gas Chromatography – Mass Spectrometer (GC-MS) method in order to provide scientific validation for their use and as potential source of drug development. Phytochemical profile of air-dried Chrysophyllum albidum seed and stem bark essential oils shows that it contains an array of biologically active substances that include alkaloids, steroids, tannin, phenol, reducing sugar and flavonoid. However, Chrysophyllum albidum seed contains cardiac glycosides and saponin which are absent in the stem bark. Antimicrobial activity was determined using agar well diffusion method. The seed part reveals comparatively great antimicrobial activity against the test organisms (bacteria and fungi) used in the study. Salmonella typhi was the most susceptible bacterial isolate with 29mm zone of inhibition at 100mg/ml, 18mm at 50mg/ml and 13mm at 25mg/ml, while Trichophyton rubrum was the most susceptible fungi isolate with 18mm and 13mm at 100mg/ml and 50mg/ml respectively. Further study on the essential oil of the Chrysophyllum albidum seed using the Gas Chromatography and Mass Spectrometer reveals fifteen bio actives chemical compounds which invariably are the most volatile of the thousands of compounds that might be present in the essential oil. The compounds are said to possess antimicrobial activity, their various heights (%) includes; hexadecanoic acid, methyl ester (2.02), Pentadecanoic acid (11.77), Cycloheptan(a)indole (1.13) , Methyl 10-trans,12-cis-octadecenoate (4.99),9-Octadecanoic acid (z)-,methyl ester (7.07), 6-Octadecanoic acid,(z)- (47.81), octadecanoic acid (14.94), 2,2,3-Trimethyl-2-3-methyl-buta 1,3-dienyl (0.91), Squalene (3.35), Chondrillasterol (0.45), 7,22- Ergostadienone (1.51), 17-(1,5- Dimethyl-3-phenylthiohex-4-enyl)-4 (0.54), Beta.-Amyrin (0.49), Lup-20(29)-en-3-ol, acetate, (3- beta) (0.77) and Phthalic acid, di(2-propylpentyl) ester (2.26). The results of this research justify the use of Chrysophyllum albidum for traditional medicine and further research on this plant parts is encouraged. [80] This study deals with the chemical composition and antimicrobial activity of essential oils of Vitex agnus castus L. The main constituents of the essential oils were characterized by GC-MS which resulted in the identification of 26 components, representing 100 % of the oil. The dominant compounds in the oil of fruits were trans-caryophyllene (19.17 %), sabinene (18.05 %) and 1,8-cineole (16.13 %), α-terpinyl acetate (6.91 %) and dihydroselarene (6.73 %). Antimicrobial activity was tested using the disc diffusion method. According to the inhibition zones, the essential oils were active against all of the tested microorganisms. The essential oils showed the susceptible inhibition zones, but they were less effective against bacterial strains compared to ampicillin and ofloxacin. The organisms most susceptible to these essential oils were Enterococcus faecalis ATCC 29212. However, further studies must be performed to confirm the safety of these oils for use as an antimicrobial agent.[81] Contamination of the environment by pharmaceuticals, quinolones among them, is recognized as an emerging issue of concern to scientists and the public. Literature on the environmental analysis of quinolones has addressed a very small percentage of these compounds, and the analytical methods developed to determine them are very scarce. By contrast, a large number of methods have been proposed for their analysis in food, which has classically been considered the source of these residues for human beings. Although both matrices, food and environment, differ, most of the information obtained from one field can be applied to the other. However, to be able to do this, there is need for critical discussion about how analytical determination is carried out in each case. This review summarizes the most relevant issues that condition the analogies and the contrasts between food and environmental matrices in the analysis of quinolones. We describe and compare the target analytes and their relevant levels. We also critically review the approaches to extraction (e.g., solvent extraction (SE), pressurized liquid extraction (PLE) and solid-phase extraction (SPE)), depending on the sample characteristics. We also detail the main analytical techniques (e.g., liquid chromatography (LC) and capillary electrophoresis (CE) combined with UV, fluorescence (FLD) and mass spectrometry (MS), immunoassays and biosensors) used to identify and to quantify quinolone residues in both matrices. We present an updated overview of the recent uses and future prospects for the different analytical methods employed in food and environmental samples.[82]
CONCLUSION
There are many analytical methods have been used to determine Ofloxacin in bulk drug and in its pharmaceutical preparations at various levels. Colorimetry, HPLC methods and HPTLC methods are simple and easy to apply. It also can be determined by voltammetry, fluorimetry, LC-MS, GC-MS, Super critical fluid extraction method, Electrophoresis methods. However, the high-performance liquid chromatographic analysis methods are often used in research because it can detect samples with lesser quantities. The HPLC methods can be applied in mixture of Ofloxacin with other drugs.
REFERENCES
Siripurapu Meghna*, Shaik Usman, Chennuboyina Dileep Kumar, B. Thangabalan, A Review on Reported Analytical Methods for Estimation of Ofloxacin, Int. J. of Pharm. Sci., 2025, Vol 3, Issue 5, 734-765 https://doi.org/10.5281/zenodo.15341908
10.5281/zenodo.15341908
