DEVELOPMENT AND CHARACTERIZATION OF GASTRORETENTIVE DRUG DELIVERY SYSTEM FOR RITONAVIR TABLETS USING NATURAL POLYMERS

Abstract

ABSTRACT Objective: The present study involves preparation and evaluation of floating tablets of ritonavir for improving the drug bioavailability by prolongation of gastric residence time.Ritonavir is an antiretroviral agent used in treatment of HIV and viral diseases has been taken as a model drug in the present investigation because of its low biological half life (3-5h). Moreover it is primarily absorbed from stomach. Materials and Methods: Ritonavir floating tablets were prepared by the dry granulation technique, using guar gum and xanthan gum as polymers, sodium bicarbonate as effervescent agent, PVP as binding agent, Di calcium phosphate as diluents, Crospovidone as swelling agent and magnesium stearate as lubricant. The prepared tablets were evaluated for various physico-chemical parameters. Results: Drug-excipient interaction studies were conducted by FTIR and DSC. The results suggested that there was no incompatibility between the drug and polymers. The prepared tablets were evaluated for their physical characteristics. All the parameters were within the pharmacopoeial limits. Further, tablets were also studied for their floating properties and in vitro drug release characteristics. The tablets exhibited controlled and prolonged drug release profiles. The developed formulation was found to be stable. Conclusion: The developed floating tablets of ritonavir exhibit prolonged release upto 12 h, and thus may improve bioavailability and minimize fluctuations in plasma drug concentrations. Key words: Ritonavir, floating tablets, gastric residence time, gastroretentive drug delivery system