Development of an In situ Gel Polymer Composite for Local and Sustained Delivery of Drugs in Vaginal Cavity

Objective: The present research work is aimed at the development of an in situ gel polymer composite to provide local and sustained delivery of therapeutic agents in the vaginal cavity. Administration of medicated gel into a vaginal cavity is very complicated, inconvenient and needs expert assistance. There is a chance of expulsion of liquid formulation from site of application, leads to poor therapeutic efficacy. The effective drug delivery system for the vaginal cavity should be of liquid for application and gel to reside in the cavity. Methods: In situ gel composed of chitosan (0.8%) cross-linked with β-glycerol phosphate (15%) and glutaraldehyde treated guar gum (0.2%) was developed. Gel was characterized for in situ gelling properties. In vitro drug release pattern of the gel was tested on a nutrient agar medium containing attenuated E. coli and B. Subtilis. In vitro diffusion pattern of gel was tested using KC-diffusion cell with Simulated Vaginal Fluid (SVF) (pH 4.2) as the diffusion medium. Results: In situ gel exhibited sharpest sol-gel transition at 35±2°C, at pH 5.4 in 62±1.31sec. The viscosity of polymer composite is 51.25±3.68 CPs at 20±2°C and 328.56±4.16 CPs at 35±2°C. The gelation time of gel was found to be decreasing as the concentration of cross-linking agent β-GP increased. Formulations exhibited a shear thinning property. Drug release from this polymeric composite was found to be highly linear and follows non-fickian diffusion mechanism. Conclusion: This advanced thermosensitive in situ gel is convenient to apply and reside in the vaginal cavity for a prolonged period of time. The gel is mucoadhesive, biodegradable and suitable for controlled drug delivery in the cavity.