Formulation and Evaluation of Floating Microsponges of Allopurinol

Abstract

The aim of the study is to develop a floating microsponges of allopurinol to minimize the frequency of dosing by increasing half life and sustained release action up to 12 hrs by single unit dosage form. Allopurinol is xanthine oxidase inhibitor drug that leads to decrease in the production of uric acid from xanthine and hypoxanthine. It is BCS class I drug. It shows absorption window in upper gastro intestinal track, which makes it suitable candidate for gastro retentive dosage forms. Floating microsponges of allopurinol was formulated with quasi emulsion solvent diffusion method using Ethyl cellulose and Eudragit EPO as a polymer. A 32 factorial design was applied to optimize the formulation, it was found that formulation containing Ethyl cellulose 175 mg and of Eudragit EPO 75 mg, % drug release of allopurinol in 12 hrs with desired % buoyancy and % entrapment and best formulation was selected. The final optimized formulation shows entrapment 90.61%, buoyancy 86.52% and in vitro drug release 94.23% up to 12 hrs. Particle size was measured by optical microscopy. By using FTIR analysis drug and polymer compatibility was observed and using SEM prepared microsponges shape and surface morphology was determined. Accelerated stability study was carried for a period of 1 month. It was found that there was no significant change in formulation.