DESIGN DEVELOPMENT AND EVALUATION OF GASTRO RETENTIVE FLOATING MICROSPHERES OF ATAZANAVIR SULFATE

The purpose of present study was to formulate the gastro-retentive floating microspheres of atazanavir sulfate to be retentive in the stomach for prolonged period of time. The gastro-retentive floating microspheres were prepared by double emulsion w₁/o/w₂ solvent evaporation technique and characterization for particle size, SEM, floating time, FTIR, DSC, and entrapment efficiency. The in-vitro drug release studies and in-vitro drug kinetics were performed for different formulations. FTIR and DSC studies revealed that the drug is compatible with excipients.  The floating time of the floating microspheres was found to be > 12h. The particle size of all the formulations was evaluated by optical microscopy method. Formulation F1 – F4 comprising HPMC as rate retarding polymer exhibits an average particle size of about 515.25µm and microspheres F5 – F8 prepared with eudragit exhibit a mean particle of about 611.4 µm. Eudragit formulations exhibit an increased entrapment efficiency which is due to its large particle size and increased viscosity. All batches prepared show an initial burst release followed by sustained release. Formulation F 1 to F4 exhibits an in-vitro release of 67.8%, 70.9%, 77.8% and 87% respectively at the end of 10^th h. Formulation F5 to F8 exhibits a release of 36.1%, 54.6%, 57.6% and 67.8% respectively at the end of 10^th h. Among all the formulations, F4 prepared with combination of HPMC and ethyl cellulose exhibits sustained release behavior. The developed floating microspheres assure the delivery of drug for a prolonged period of time.