Preparation And Evaluation Oral Buccal Patches Of Sitagliptin Phosphate As Antidiabetic Drug

Diabetes Mellitus

DM is one of the most prevalent chronic diseases and a leading cause of morbidity and mortality on developed and in developing countries. It is estimated that 382 million of people have DM and, according to a recent report, the number of diabetic patients will reach 592 million by the year 2035 and In India, there are estimated 77 million people above the age of 18 years are suffering from type 2 diabetes and nearly 25 million are prediabetics (at a higher risk of developing diabetes in near future). Therefore, it urges the study of this pathology and its consequences to cells, organs and whole body. DM is described as a group of metabolic disorders characterized by chronic hyperglycemia resulting from defects in insulin action, insulin secretion, or both. This deficiency leads to disturbance in the metabolism of carbohydrates, fat and protein, which causes systemic complications and co-morbidities namely cardiovascular and renal failure. The most predominant types of DM are type 1 diabetes mellitus and type 2 diabetes mellitus. Type two Diabetes is characterized by hyperglycemia that results from insulin resistance plus variable degrees of insufficient insulin secretion. Although new lifestyles of modern societies seem to be the triggering pathogenic elements, genetic factors are also reported to be involved in the pathogenesis of Type two Diabetes In early stages of the disease, insulin production is disproportionately low for the degree of insulin sensitivity, which is usually increased. Thus, the ability of pancreatic betacells to produce adequate amounts of insulin in post- prandial glycemia is profoundly compromised. These cells’ func- tional inability is the main determinant of hyperglycemia and is known to progress over time. As a result, most patients with Type two Diabetes will gradually need more complex therapeutic procedures to control hyperglycemia. Normally, the alterations start in diet and exercise regimens and progress to monotherapy, dual therapy, or multi-agent therapy followed by insulin administration in combina- tion or not with other antidiabetic drugs. Thus, the demand for antidiabetic drugs is very high and new products are regularly pre- sented. Although its safety is assured, these drugs have multiple modes of action and effects throughout the body. Furthermore, the complexity of Type two Diabetes led to the establishment of an intermediate state, often called as pre-diabetes. In this prodromal stage of Type two Diabetes, the patients present glycemic values higher than normal, but lower than Type two Diabetes thresholds. Moreover, pre-diabetic patients pre- sent impaired fasting glycemia and/or impaired glucose tolerance. This pre-diabetic condition may be triggered by sedentary lifestyle and the ingestion of high fat and saturated fatty acid diets. As a consequence, several metabolic changes in organs and cellular systems occur. These patients have increased risk for Type two Diabetes as well as for cardiovascular disease. However, this pre-diabetic stage does not imply the progression to Type two Diabetes, which can be prevented or delayed by lifestyle and drug-based interven- tions illustrating the relevance of an early diagnostic and of the study of this prodromal stage of Type two Diabetes. [1-16]ORAL ROUTE BENEFITS

The oral route of administration is often preferred by patients for several reasons, making it a popular choice for delivering medications like sitagliptin for type 2 diabetes. Here are the key reasons:

1. Convenience and ease of use

Non-Invasive:

Oral medications do not require injections, which can be painful and intimidating for many patients.

Simple Administration:

Swallowing a pill is straightforward and can be done without medical assistance, making it more convenient for self-administration.

2. Comfort and compliance

Less Discomfort:

Oral medications avoid the discomfort associated with needles and injections, which can lead to better patient compliance.

Ease of Routine Integration:

Taking a pill can easily be incorporated into daily routines, such as during meals, which enhances adherence to the medication regimen.

3. Safety and accessibility

Lower Risk of Infections:

The oral route minimizes the risk of infections that can occur with injections if proper sterile techniques are not followed.

Widely Available:

 Oral medications can be stored and transported easily, making them more accessible for a broader population, including those in remote areas.

iv.        Psychological benefits

Reduced Anxiety:

Many patients experience anxiety or fear related to needles and injections. Oral medications help alleviate this anxiety.

Greater Sense of Normalcy:

 Taking oral medication feels more like a routine part of daily life and less like a medical procedure, contributing to a sense of normalcy and control over one’s health.

v.         Pharmacokinetic advantages

Controlled Release Options:

 Many oral medications can be formulated as extended-release or controlled-release forms, providing more stable blood levels of the drug and reducing the frequency of dosing.

Gastrointestinal Absorption:

The gastrointestinal tract is designed to absorb nutrients and medications effectively, providing a suitable pathway for drug delivery.

vi.        Economic factors

Cost-Effective:

Oral medications are often less expensive than injectable forms, both in terms of production and distribution.

Lower Healthcare Costs:

Reducing the need for healthcare professional involvement in drug administration can lower overall healthcare costs. Overall, the oral route of administration aligns well with patient preferences for comfort, convenience, and ease of use, thereby enhancing medication adherence and overall treatment outcomes.

THE STRUCTURE OF THE ORAL MUCOSA

The oral mucosa is composed of an outermost layer of stratified squamous epithelium. Below this lies a basement membrane, a lamina propria followed by the submucosa as the innermost layer. The epithelium is similar to stratified squamous epithelia found in the rest of the body in that it has a mitotically active basal cell layer, advancing through a number of differentiating intermediate layers to the superficial layers, where cells are shed from the surface of the epithelium. The epithelium of the buccal mucosa is about 40-50 cell layers thick, while that of the sublingual epithelium contains somewhat fewer. The epithelial cells increase in size and become flatter as they travel from the basal layers to the superficial layers.

       
           
       
    Figure no. 1: The Structure of Oral mucosa

Oral route is considered as the most convenient and preferred route for administration of therapeutic agents. Tablets and capsules are the most popular oral solid dosage forms used today. However Bed ridden, unconscious, paralyzed, paediatric and geriatric patients as well as patients who are travelling without having access to water experience greatest difficulty in swallowing the conventional dosage forms like tablets, capsules because of tremors of extremities, dysphasia and hence do not take their medications as prescribed by physician. Buccal route of drug delivery is a good alternative amongst these various routes of drug delivery. It provides direct access to the systemic circulation through the jugular vein bypassing the first pass hepatic metabolism leading to high bioavailability. Attachment of a synthetic natural macromolecule to a biological tissue for an extended period of time defined as bioadhesion. When a substrate adheres and interacts primarily with the mucus Layer, this phenomenon being referred to as mucoadhesion. Buccal patch can be prepared using mucoadhesive polymers, by which rapid onset of action may attained.

       
           
       
    Figure no.3. Buccal patch

PHARMACEUTICAL APPLICATION

1. Pain Management

Opioid Analgesics:

Buccal patches are used for delivering opioid analgesics (e.g., fentanyl) for rapid pain relief, particularly in chronic pain and cancer patients.

Non-Opioid Analgesics:

Other pain medications can also be delivered for local pain relief within the oral cavity.

2. Hormone Replacement Therapy

Sex Hormones:

Hormones such as testosterone or estradiol can be administered via buccal patches for conditions requiring hormone replacement therapy, providing a steady release and improved bioavailability.

3. Cardiovascular Treatments

Nitroglycerin:

Used for angina pectoris, buccal patches can provide rapid relief by delivering nitroglycerin directly into the bloodstream.

4. Smoking Cessation

Nicotine Replacement:

Buccal patches can be an effective tool for delivering nicotine in a controlled manner to help individuals quit smoking.

5. Systemic Delivery of Peptides and Proteins

Insulin and Other Peptides:

Buccal patches can be used to deliver peptides and proteins that are otherwise degraded in the gastrointestinal tract, improving their bioavailability.

6. Treatment of Oral Conditions

Antifungal and Antibacterial Agents:

For treating oral infections like oral thrush, buccal patches can provide localized delivery of antifungal or antibacterial agents.

Anti-inflammatory Drugs:

These can be used to treat inflammatory conditions within the oral cavity.

7. Neurological Disorders

Antiepileptic Drugs:

Buccal patches can be used to deliver drugs for managing epilepsy, providing a more consistent and controlled release compared to oral tablets.

Parkinson’s Disease:

Certain medications for Parkinson’s disease can be administered buccally to manage symptoms more effectively.

LITERATURE REVIEW

Shewale Vaibhav L,et al.(2021)

The aim of this article is to study the buccal patches. Buccal patch is a nondissolving thin matrix modified release dosage form composed of one or more polymer films or layers containing the drug and/or other excipients. Buccal patches have been become an interesting area of novel drug delivery system as the dosage forms designed for buccal administration should not cause irritation and should be small and flexible enough to be accepted by the patient. The study of buccal patches include its introduction, types of buccal patches, advantages, limitation, potential uses of buccal patches, polymer used, methods of preparation, evaluation.

Aswathy Bose et al.(2020)

The aim of present work was to formulate and evaluate Sitagliptin buccal patch using solvent casting method. Buccal patch gained importance as it overcomes the limitations of current routes of administration, provides rapid onset of action by releasing drug directly to systemic circulation through oral mucosa by mucoadhesion. The formulated buccal patches were evaluated for various parameters like film thickness, surface pH, folding endurance, weight variation, % moisture loss, tensile strength, % elongation, drug content uniformity, and in vitro dissolution studies The optimized formulation (F4) containing HPMC E5 and Eudragit RL 100 polymer combination in 1:1 ratio showed highest in vitro dissolution (99.7 %) and satisfactory stability.

Maria J. Meneses et al. (2015)

Diabetes mellitus (DM) is one of the most prevalent chronic diseases and has been a leading cause of death in the last decades. Thus, methods to detect, prevent or delay this disease and its co-morbidities have long been a matter of discussion. Nowadays, DM patients, particularly those suffering with type 2 DM, are advised to alter their diet and physical exercise regimens and then proceed progressively from monotherapy, dual therapy, and multi-agent therapy to insulin administration, as the disease becomes more severe. Although progresses have been made, the pursuit for the “perfect” antidiabetic drug still continues. The complexity of DM and its impact on whole body homeodynamics are two of the main reasons why there is not yet such a drug. Moreover, the molecular mechanisms by which DM can be controlled are still under an intense debate. As the associated risks, disadvantages, side effects and mechanisms of action vary from drug to drug, the choice of the most suitable therapy needs to be thoroughly investigated. Herein we propose to discuss the different classes of antidiabetic drugs available, their applications and mechanisms of action, particularly those of the newer and/or most widely prescribed classes. A special emphasis will be made on their effects on cellular metabolism, since these drugs affect those pathways in several cellular systems and organs, promoting metabolic alterations responsible for either deleterious or beneficial effects. This is a crucial property that needs to be carefully investigated when prescribing an antidiabetic

Palanisamy Arulselvana et al. (2014)

Diabetes mellitus (DM) is a common metabolic/endocrine disorder throughout the world and cause serious medical problems to human health. Recent drastic changes over human dietary habits and contemporary lifestyle lead to various chronic disorders/diseases particularly metabolic diseases including obesity. Traditional medicinal plants and their active phyto-constituents have been used throughout the world for the therapy of diabetes and associated secondary complications. Among many medications and other alternative medicines, numerous herbs have been well-known to cure and prevent diabetes. Several traditionally important medicinal plants have been investigated for their beneficial use in different types of diabetes and its complications. The effects of these plants may delay the development of diabetic complications and alter the metabolic abnormalities using a variety of cellular and molecular mechanisms. A considerable number of active medicinal plants and their bioactive compounds were subjected to clinical trials and were found effective. Moreover, during the pastfew years many phyto-constituents responsible for antidiabetic effects have been isolated from plants showed higher potential than synthetic drugs. As a result, recently, considerable scientific attention has been directed towards classification/identification of traditional medicinal plants with antihyperglycemic ability that may be used for daily consumption along with the food. This review paper mainly focuses on natural phytoextracts with their pharmacological mechanism of action and their preclinical experimental model, which attracts the attention of pharmacologist, phytochemist and pharmocognosist for further scientific research towards endocrine metabolic disorder. ©

Pradeep Kumar Koyi et al. (2013)

 Buccal route is an attractive route of administration for systemic drug delivery and it leads direct access to the systemic circulation through the internal jugular vein bypasses drugs from the hepatic first pass metabolism provides high bioavailability. Buccal bioadhesive films, releasing topical drugs in the oral cavity at a slow and predetermined rate, provide distinct advantages over traditional dosage forms for treatment of many diseases. This article aims to review the recent developments in the buccal adhesive drug delivery systems to provide basic principles to the young scientists, which will be useful to circumvent the difficulties associated with the formulation design.

AIM AND OBJECTIVES OF THE STUDY    

Aim:

To develop and evaluate buccal patches containing Sitagliptin for effective management of diabetes mellitus through sustained drug release and enhanced bioavailability.

OBJECTIVES:

• Develop a Novel Drug Delivery System:

Formulate oral buccal patches incorporating sitagliptin to provide an alternative to traditional oral administration.

• Enhance Drug Bioavailability:

Bypass the gastrointestinal tract and first-pass metabolism in the liver to increase the bioavailability of sitagliptin.

• Improve Patient Compliance:

Provide a non-invasive, convenient, and user-friendly method of drug delivery that enhances patient compliance, especially in those who have difficulty swallowing pills.

• Achieve Controlled Drug Release:

Design patches to provide controlled and sustained release of sitagliptin, maintaining therapeutic levels over an extended period.

• Evaluate Physicochemical Properties:

Characterize the patches in terms of thickness, weight uniformity, drug content, surface pH, and swelling index to ensure consistent quality and performance.

• Assess Mucoadhesive Strength:

Measure the adhesive strength of the patches to ensure they adhere effectively to the buccal mucosa, allowing for efficient drug delivery.

• Investigate In-vitro Drug Release:

Conduct in-vitro studies to analyze the drug release profile from the buccal patches and compare it to traditional oral dosage forms.

• Determine Safety and Biocompatibility:

Assess the biocompatibility and safety of the buccal patches through appropriate toxicological studies

Plane Of Work:

       
           
       
    Figure no 4: Plan of work

DRUG AND EXCIPIENT PROFIL:  

Drug Profile:                                        

       
           
       
    Figure no.5.Structure Sitagliptin Phosphate

IUPAC Name:

(R)-4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro [1,2,4] triazolo[4,3-a] pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl) butan-2-amine

Boiling point:

529.9 °C

Formula:

C16H15F6N5O

Molar mass:

407.31 g/mol

Routes of administration:

Oral Route

Type:

Type 2 Anti Diabetic Drug

Class:

dipeptidyl peptidase-4 enzyme inhibitors.

Half life :

11 to 12 hrs

Shelf life:

2 years

MECHANISM OF ACTION

Sitagliptin is an oral, once-daily and highly selective dipeptidyl peptidase-4 (DPP-4) inhibitor for the treatment of patients with type 2 diabetes. Inhibition of DPP-4 activity by sitagliptin enhances fasting and post- prandial levels of the intact incretins, glucagon-like pep- tide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). These incretins play a role in glucose homeostasis by increasing insulin release in response to a meal; GLP-1 also decreases glucagon release. Both of these effects are glucose-dependent.

       
           
       
    Figure no.6.Mechanism of action of Sitagliptin

EXCIPIENTS:

HPMC:

       
           
       
    Figure no.7.Struture of HPMC

IUPAC Name:

Cellulose, 2-hydroxypropyl methyl ether

Formula:

C56H108O30

Soluble:

Water

Boiling point:

1,102 °C

Molar mass:

1261.4 g/mol

Uses:

• Bioadhesive Agent
• Controlled Release
• Film Forming Agent

Eudragit RL 100:

       
           
       
    Figure no.8.Eudragit RL 100

IUPAC Name:

Poly (methacrylic acid-co-ethyl acrylate) 1:1.

Formula:

C11H21NO4

Molecular mass:

32000 g/mol

Soluble:

Methanol

Uses:

• Controlled Drug Release:
• Bioadhesion
• Permeability

Methyl Alcohol:

       
           
       
    Figure no.9. Methyl Alcohol

IUPAC Name:

Methanol

Formula:

CH?OH

Molar mass:

32.04 g/mol

Boiling point:

64.7 °C

Uses:

• Solvent for Polymer Preparation:
• Extraction and Purification:
• Cleaning and Sterilization:

Citric Acid:

       
           
       
    Figure no.10.Stucture of Citric acid

Formula:

C?H?O?

Molar mass:

192.124 g/mol

Soluble :

Water, Acetone, Dimethyl sulfoxide, Ethyl acetate

 Uses:

• pH Adjustment
• Buffering Agent
• Permeation Enhancer

Glycerol:

       
           
       
    Figure no.11.Stucture of Glycerol

IUPC Name:

propane-1,2,3-triol

Formula:

C?H?O?

Molar mass:

92.09382 g/mol

Density:

1.26 g/cm?3;

Boiling point:

290 °C

Uses:

• Plasticizer
• Humectant
• Solvent

MATERIAL AND METHOD:

List of material

Table no 1: List of Materials

Preformulation studies

A preformulation study is an essential step in drug development where the physical and chemical properties of a drug substance are evaluated before formulating it into a dosage form. This helps in understanding its behavior, stability, and compatibility with excipients, aiding in the design of an effective and stable formulation. [chat gpt]

Melting Point:

Take a capillary tube and close its one end by heating the end in the flame for 2-3 minutes while continuously rotating it. Take Sitagliptin Phophate fine powder. Dip the open end of the capillary tube in the finely powdered Sitagliptin Phophate .Gently tap the capillary tube on the table to fill the compound in the capillary tube to about a length of 1–2 cm. Attach the capillary to the thermometer with the rubber band and dip the thermometer in Thieles tube containing paraffin oil. Keep continuous watch of the temperature and note the temperature as soon as the substance starts to melt.

Fourier transform infrared spectroscopy (FT-IR):

FTIR spectrum was used as an analytical technique for identification of pure drug sample. The spectra for the sample were recorded using a Bruker Vertex 70 FTIR spectrophotometer by KBr pellet method. The samples were analysed by mixing with potassium bromide (1:10) individually and pressed to form a thin pellet by applying pressure using KBr press. The formed pellets were placed within the sample holder. Spectral scanning was taken in the wavelength region between 4000-400 cm?1. FTIR scans of Sitagliptin phosphate   were recorded

Spectroscopical analysis:

Determination of Lambda max by UV Spectroscopy:

For determining Lambda max of Sitagliptin Phophate,10 mg of drug was dissolved in Methanol  and diluted to 100 ml to form strength of 100 ?g/ml with the same solvent. It was then scanned in the range of 400 to 200 nm using Methanol as a blank using UV-Visible spectrophotometer (Machine Name) and the maximum wavelength will be determined.

Preparation of calibration curve:

Calibration curve of Sitagliptin Phosphate was prepared with the help of UV spectroscopy.

Calibration curve of Sitagliptin Phosphate was prepared in Methanol.

Calibration curve:

Preparation of stock solution:

Accurately weighed 10 mg of Sitagliptin Phophate    was transferred in 100 ml volumetric flask. The drug was dissolved and diluted upto the mark with water to give a  solution with concentration of 100 ?g/ml.

Preparation of working solution:

Appropriate aliquots from stock solution of Sitagliptin Phophate (0.2, 0.4, 0.6, 0.8, 1 and 1.2 ml) were accurately withdrawn in 10 ml volumetric flask and diluted upto the mark with methanol to obtain the final concentration of solution in range of 2-12 ?g/ml and scanned at Lambda max. Absorbance of these solutions of Sitagliptin Phophate were recorded at their Lambda max using methanol as blank.

Method of preparation

• Buccal patch was prepared by solvent casting method. Polymers like HPMC, and Eudragit RL 100 were used to formulate buccal patch using Glycerol as plasticizer.
• Citric acid was used as saliva stimulating agent, Saccharin sodium as sweetening agent. Formulations F1 to F5 were prepared using different concentrations and ratios of HPMC and Eudragit RL 100.
• The formulation design of Sitagliptin buccal patch is given in Table.
• The specified amount of polymers HPMC and Eudragit RL100 was dissolved in solvent methanol.
• The required amount of plasticizer was added to patch forming solution.
• Drug was dissolved in small amount of solvent and added to polymer solution
• Sweetener and saliva stimulating agent were added one by one into above solution with continuous stirring to form a clear aqueous solution.
• The solution was kept undisturbed until the air bubbles get removed. The aqueous solution was poured into the petridish and was air dried.
• The patch was carefully removed from the Petridish and cut into required size suitable for testing.
• The formulated patch was further stored in desiccators for 2 days and wrapped in aluminum foil and packed in self-sealing covers.

  ---

  Batch Formulation:

Evaluation test

FT-IR Study

The IR spectra were recorded using FTIR spectrophotometer. The samples were prepared by mixing the drug and the excipients in 1:1 ratio and the mixtures were stored in closed containers for 1 week. FTIR spectrum of the samples was taken using potassium bromide Pellet technique. The physical mixtures of Sitagliptine and excipients were scanned in the wavelength region between 3800 and 650 cm-1 and compared to check compatibility of drug with excipient.

Folding endurance

Folding endurance was determined by repeatedly folding the patch at the same place till it breaks. The value of folding endurance obtained from the number of times it folded without breaking.[48]

Weight Variation

Individually weighing randomly selected patches and then calculating average weight to determine weight variation. Digital weighing balance was used to measure each patch. The S.D of weight was computed from the mean value.[49-50]

Surface of Ph

The pH meter was calibrated using buffer of pH 4.0 and 7.0 before taking measurement. The patches to be tested were moistened using phosphate buffer pH 6.8 in a petridish and kept for 30 sec. The pH of the formulation was noted after bringing the electrode of pH meter in contact with the surface and allowed to equilibrate for 1 min.

 Drug content Uniformity

To determine drug content uniformity, 10 dosage units13,14 were individually assayed. The patch was then transferred into a graduated flask, dissolved in 100 ml methanol and the flask was shaken continuously. The solution was filtered after suitable dilutions with methanol and the absorbance was measured at 267 nm using UV spectrophotometer and the drug content was calculated.[51-52]

Percentage Moisture loss

Three patches of area 2cm x 2cm were accurately weighed and kept in desiccators15,16 for 3 consecutive days. Patches were removed and reweighed. The % moisture loss was calculated using the formula.[53-54]

In vitro dissolution study

The dissolution study of the patch17-19 was carried out using modified type 5 dissolution apparatus at 37°C ± 0.5°C using 300 ml of simulated saliva (pH 6.8) as dissolution media. The agitation speed of paddle was 50 rpm. At predetermined time intervals, 5 ml of sample was withdrawn and replaced with fresh medium. The sample was filtered through Whatmann filter paper and analyzed by UV spectrophotometer at 267 nm.[55-56]

RESULT AND DISCUSSION

Melting Point:

The pure drug sitagliptin phosphate's reported melting point is 213-2160C while the observed drug's melting point is 2100C. It indicate that the drug in the powder is pure nature and that the powder is sitagliptin phosphate.

Tabel No.3. Melting point of drug

Calibration  curve:

The graph of Concentration Vs Absorbance for pure Sitagliptin Phosphate was found to be in the  concentration range  of 0.2-1.0 ?g/ml. with the regression coefficient of 0.996.

Tabel No.4. Calibration curve of Sitagliptin

Figure no 12: UV Absorption spectrum of Sitagliptin

Fourier Transform Infrared Analysis

Using Fourier transform infrared spectroscopy, the infrared spectra of pure Sitagliptin Phosphate and a physical combination were obtained (Agilent carry 630). This indicates that the drug , along with the excipients, maintained its usual value throughout the formulation. This observation unequivocally shows that the drug and excipients employed in this investigation did not interact. The infrared (IR) spectrum analysis of the pure drug of Sitagliptin Phosphate revealed several key absorption bands indicative of specific functional groups. An absorption band at 1423.99 cm??1;, within the range of 1350-1480 cm??1;, corresponds to the C-H bending vibrations characteristic of alkanes. Additionally, a prominent absorption peak at 1688.10 cm??1;, situated between 1600-1700 cm??1;, signifies the presence of a carbonyl group, attributable to the C=O stretching vibrations. The analysis also identified an absorption at 873.91 cm??1;, which falls in the range of 880±20 cm??1;, indicating the C-H bending vibrations associated with a 1,2,4- trisubstituted benzene ring. Furthermore, a distinct absorption band at 2358.13 cm??1;, within the range of 2000-2400 cm??1;, corresponds to the N=C=O stretching vibrations, signifying the presence of an isocyanate group. These IR spectral findings provide crucial insights into the functional groups present within the sample, aiding in the structural elucidation of the compound.

       
           
       
   Figure no 14: FT-IR image of Sitagliptin phosphate

Table No. 6. Major observed IR peaks of Sitagliptin phosphate