Formulation and Evaluation of Gastroretentive Floating Microspheres of Rilpivirine Hydrochloride

Background: Systems of floating drug delivery have a bulk density less than gastric fluids and thus it remains buoyant in the stomach without having any effect on gastric emptying rate for prolonged period of time. Rilpivirine is an antiviral drug is used to treat human immunodeficiency virus (HIV), to combat the spread of (HIV), delivery of long acting; antiretroviral (ARV) drugs would be very beneficial for prevention and treatment. However the poor bioavailability of the drug requires attention in improving it and the technique of floating microspheres was investigated for the same objective. Methods: Floating microspheres of Rilpivirine are formulated by Emulsion – solvent diffusion technique using Ethyl cellulose and carbopol as polymers. The floating microspheres were subjected to evaluation for micrometric properties, percentage yield, particle size, drug polymer compatibility, scanning electron microscopy (SEM) and in vitro drug release studies and kinetics of drug release. Results: The results show that as the polymer concentration increases, the particle size, percentage yield, in vitro drug release was affected of floating microspheres. The micromeritic test was performed to confirm the particle size, and SEM results confirmed their hollow structure with smooth surface. Optimized formulation has shown good percentage yield, encapsulation efficiency, drug release was 98.25% at the end of 12 hrs, the release was found to follow fickian diffusion with excellent drug release for long period of time. Conclusion: The results conclude that floating microspheres formulation of rilpivirine HCl could be effective tool in improving the bioavailability of drug for improved absorption.