Periodontal disease is a general term which encompasses several pathological conditions affecting the tooth supporting structures. Periodontal diseases include conditions such as chronic periodontitis, aggressive periodontitis, systemic disease-associated periodontitis and necrotizing periodontitis. These conditions are characterized by a destruction of the periodontal ligament, a resorption of the alveolar bone and the migration of the junctional epithelium along the tooth surface. The clinical signs of periodontitis are changes in the morphology of gingival tissues, bleeding upon probing as well as periodontal pocket formation. This pocket provides an ideal environment for the growth and proliferation of anaerobic pathogenic bacteria.The microorganisms colonizing the sub-gingival area represent the principal etiological factor in the development of the inflammation and tissue destruction. Antimicrobial and Anti

inflammatory agents are used to treat periodontal diseases. These agents are associated with drawbacks like short biological half-life and inability of the active product to be retained locally for a sufficient period of time. So, these drawbacks would be markedly reduced by a novel technique, bio adhesive gel incorporated drug loaded microspheres which directly incorporates active agent into the periodontal pocket.

Diseases Of The Periodontium:

The Therapeutic Aspects Diseases of the periodontium (gingivae, cement, alveolar bone and periodontium) are frequent, presenting in children as well as in adults. The etiology of these diseases is complex; clinical manifestations are different making the classification more difficult. One classification, presented in 1999, foremost is based on the etiology of these diseases.

Types Of Microspheres

Floating microspheres

In floating types the bulk density is less than the gastric fluid and so remains buoyant in stomach without affecting gastric emptying rate. The drug is released slowly at the desired rate, if the system is floating on gastric content and increases gastric residence and decreases fluctuation in plasma concentration. Moreover it also reduces chances of striking and dose dumping. One another way is it produces prolonged therapeutic effect and therefore reduces dosing frequencies.

Drug Profile

 Ketorolac tromethamine

Chemical Name   :  (±)-5-benzoyl-2,3-dihydro-1H-pyrrolizine-1-carboxylic acid,2

amino-2-(hydroxymethyl)-1,3-propanediol.

Molecular Formula  :  C₁₅H₁₃O₃.C₄H₁₁N0₃

Type                         : small molecule

Structure :

A pyrrolizine carboxylic acid derivative structurally related to indomethacin. It is an NSAID and is used principally for its analgesic activity.(from Martin-dale The Extra Pharmacopoeia,32^st ed)

Description:  It is white to off white, crystalline powder.

Solubility : freely soluble in water and in methyl alcohol ,slightly soluble in alcohol, practically insoluble in acetone

Synonyms:Ketorolac,KetorolacTromethamine,Ketorolaco(Spanish  Ketorolacum(Latin)

Excipients Profile

4.2.Carboxy Methyl Cellulose Sodium

Synonyms       : Sodium cellulose glycolate, Na CMC, CMC, cellulose gum, sodium CMC;

Chemical names    : Sodium salt of carboxymethyl ether of cellulose

Chemical formula  : 

[C₆H₇O₂(OH)x(OCH2COONa)y]n

Where,

 n is the degree of polymerization

        x = 1.50 to 2.80

        y = 0.2 to 1.50

        x + y = 3.0

       (y = degree of substitution)

Structural formula:
       
           
       
where R = H or CH2COONa

Empirical formula: The USP describes Carboxymethyl cellulose Sodium as the sodium salt of poly carboxymethyl ether of cellulose.

molecular weight: 90,000-7,00,000.

Solubility: practically insoluble in acetone, ethanol (95%), ether , and toluene. Easily

dispersed in water at all temperatures, forming clear, colloidal solutions.

CARBOPOL-934:

Carbopol 934 polymer is a cross-linked polyacrylate polymer. It offers excellent stability at high viscosity and produces thick formulations for opaque gels, emulsions, creams and suspensions. Carbopol 934 polymer has short flow properties in aqueous systems. It contains not less than 56% and not more than 68% of carboxylic acid groups.

Synonyms: Acritamer , acrylic acid polymer

carboxy vinyl polymer.

Non proprietary names : BP carbomer , USP

carbomer.

Chemical name         : Carboxyl polymethylene

Empirical formul : ( C₃H₄O₂)X (-C₃H₅Sucrose)y

Structure :

       
           
       
Category : bioadhesive , emulsifying ,

suspending  and viscosity enhancing agent , tablet binder and release – modifying agent.

Description  : White, fluffy , acidic , hygroscopic powder with a slight characteristic odour.

Solubility     : after neutralization with alkali hydroxidres or amines, soluble in water, in ethanol (96%) and in glycerol.

Hydroxy Propyl Methyl

Cellulose:

Chemical name : Cellulose 2 hydroxy propyl

methyl ether.

Synonym : Methyl hydroxyl propyl cellulose

Empirical formula : HPMC is propylene glycol ether of methylcellulose. It contains methoxy (-OCH₃) and hydroxyl proxy (-OCH₂CHOHCH₃) groups confirming to the limits for the types of HPMC.

Molecular weight : 86,000

Functional category : Emulsifying agent, suspending agent and stabilizer in gel and ointments,adhesive in plastic bandages, binder in tablet granulation (2-5%); high viscosity grades are used to retard the release of water soluble drugs.

Description : An odourless, taste less, white or creamy white fibrous or granular powder.

ACETONE

Synonyms  : acetonum, dimethylformaldehyde , dimethyl ketone, b- ketopropane, pyroacetic ether

Description  : acetone is a colourless volatile , flammable ,transparent liquid with a sweetish odour and pungent sweetish taste.

Structure :

       
           
       
Solubility : it is freely soluble in water an ethanol (95%)

Empirical formula    : C₃H₆O _58.08

MATERIALS AND METHODS

5.1 Materials

Materials used in present study

Table no 5.1:    List of ingredients used in the study

   Equipment:

Equipments used in the present study

Table no 5.2 : List of equipments used in the study

Formulation Development:

5.3.2.a. Preparation of microspheres by Solvent evaporation method

Floating Microspheres containing the anti-inflammatory drug Ketorolac tromethamine were prepared by a solvent evaporation method (table 5.3). In this technique, drug and polymer (HPMC K4M, Carbopol 940, and Ethyl cellulose in various proportions were dissolved in a 20 ml acetone which was placed in a small beaker with a magnetic bead on the magnetic stirrer at room temperature. The drug-polymer mixture was poured into 30 ml liquid paraffin containing Tween 80 maintained at a temperature of 30-40 °C and subsequently stirred by the stirrer at ranging agitation speed i.e. 1200 rpm (revolution per minute) for 60 min to allow the volatile solvent to evaporate. The microspheres formed were filtered, washed with n-hexane and air-dried for 24 h, and stored in a desiccator

Table 5.3 Formulation table of microspheres

5.3.3. Evaluation Of Microspheres:

Micromeritic properties

Bulk density

Bulk density is the ratio of the total mass of the powder to the bulk volume of powder. It is measured by pouring weighted microspheres of about 1g into a measuring cylinder and the bulk volume is noted down.

Bulk density = ????????????????????? ???????? ????????? ????????????????er/tapped

Volume

Tapped density

Tapped density is the ratio of the total mass of the powder to the tapped volume of the powder. Tapped density = ????????????????????? of ????????? ???????????????????????? /???????????????????????? ????????????????????????

Hausner’s ratio

Hausner’s ratio is the ratio of the tapped density    

to the bulk density.

Angle of repose⁴⁵

The angle of repose (?) is used to measure the frictional forces in a loose powder.

 ? = tan-1h/ r                 

 r = Radius of the heap.

 where h = height of the heap

% Compressibility index

The percentage yield of the microspheres was determined by weighing the prepared microspheres of each formulation divided by the total amount of all non-volatile components which were used for the preparation of microspheres.

Carr’s Index = Tapped density?Bulk density Tapped density X 100

Particle size analysis

Particle size analysis of drug-loaded floating microspheres was performed by optical microscopy. Few microspheres were suspended in purified water (10 ml). The sample was placed on a clean glass slide and placed on a mechanical stage of the microscope. The eyepiece of the microscope fitted with a micrometre and the size of the spheres was determined

Drug entrapment efficiency

The amount of drug entrapped was determined by crushing the microspheres in mortar and pestle. 50 mg was used for the evaluation. This was extracted with the aliquots of 0.1N hydrochloric acid (HCl). The extract was transferred to100 ml volumetric flask and the volume was made up with 0.1N HCl (pH-1.2). The solution was filtered and the absorbance was measured spectrophotometrically with suitable dilutions at a particular wavelength against the appropriate blank. The percent drug entrapped was calculated by the formula which is as follows

 % Entrapment Efficiency = Practical Drug Content /Theoretical Drug Content X 100

Floating capacity

An in vitro study was carried out to determine floating capacity. 50 mg floating microspheres were placed in simulated gastric fluid (pH 1.2, 100 ml) containing tween 20 (0.02w/v %) and stirred on a magnetic stirrer at 100rpm. After 12h, the layer of buoyant microspheres was separated from the settled microspheres by filtration. Microspheres of both types were collected, dried, and weighed. The buoyancy of microspheres was determined using the following formula

Buoyancy (%) = Wf /Wf+Ws X 100

 where, Wf = Weight of floating microsphere

Determination of percentage yield

The prepared microspheres were collected and weighed. The measured weight was divided by the total amount of all non-volatile components, which were used for the preparation of microspheres. The % yield was calculated by following formula

% yield = actual weight/total weight of drug and polymer X 100

Where WRec = Weight of microspheres recovered

Determination of percentage of drug loading

The percentage of Ketorolac tromethamine

loading in microspheres can be estimated using

L=Qm/Wm x100

where, L is the loading (%) of microspheres, Qm is the quantity Ketorolac tromethamine present in Wm of microspheres and Wm is the weight of the microspheres in grams.

Fourier Transform Infrared Spectroscopy

Drug polymer interactions were studied by FTIR spectroscopy. The spectra were recorded for pure drug and drug loaded microspheres using FTIR. A pellet of approximately 1 mm diameter of drug was prepared by compressing 3-5 mg of the drug with 100-150 mg of potassium bromide in KBr press (Model M-15, Techno Search Instruments). The pellet was mounted in IR compartment and scanned between wave number 4000 – 400 cm-1 using a Shimadzu Model 8400 FTIR.

In vitro drug release studies

An in vitro drug release studies were carried out in USP type II (Paddle type) dissolution apparatus using simulated gastric fluid (pH-1.2) as dissolution medium under sink conditions. Accurately weighed samples of floating microspheres were introduced into 900 ml of dissolution medium maintained at 37±0.5 °C with paddle rotating at 100rpm. The adequate samples were withdrawn at the interval of 1 hour and the same volume of fresh medium was refilled to maintain sink condition. After suitable dilutions, the samples were analysed

spectrophotometrically at a specific wavelength. Dissolution data was analysed for calculating the amount of drug release and percentage cumulative drug release at different time intervals.

Drug content determination

 Drug content was determined using UV-Spectrophotometer. Drugloaded microspheres were crushed and 100 mg was suspended in 100 ml 0.1N HCl solution. This suspended solution was kept for 24h. It was stirred for 5 min and filtered. Ciprofloxacin content in the filtrate was determined spectrophotometrically at 275 nm using a regression derived from the standard curve .

Swelling index determination

The swelling index behaviour of the floating microspheres was measured by studying its weight gain. To determine the swelling index the microspheres were kept in the dissolution apparatus using the dissolution medium 0.1N HCl at 37±0.5 °C. After 0.5, 1, 2, 3, 4, 5, and 6 h, each microsphere from the dissolution apparatus was withdrawn, blotted with tissue paper to remove the excess water, and weighed on the analytical balance. The experiment was performed in triplicate at each time point. The swelling index was determined by the following formula

Swelling Index = Wet weight of the microspheres?Dry weight of the microspheres /  Dry weight of microspheres

RESULTS AND DISCUSSION

The present investigation was carried out on the development and characterization of floating microspheres incorporating ketorolac tromethamine loaded microspheres for periodontal therapy by using different polymers like Ethyl cellulose, HPMC and solvent.

Ketorolac tromethamine pure drug