Formulation and Optimization of Porous Osmotic Pump based Controlled release System of Ritonavir for the Treatment of HIV Infection

Abstract

The current research involves the development of controlled porosity osmotic pump (CPOP) tablets of ritonavir for the treatment of HIV infection. Core tablets were prepared by wet granulation method using hydroxyl propyl methyl cellulose (HPMCE5LV) polymer, mannitol as osmogen, MCC as diluents and other additives. The CPOP tablets were coated with cellulose acetate as wall forming material, poly ethylene glycol as flux regulating agent, and sorbitol acts as pore forming material in SPM. The prepared tablets were evaluated for FTIR, DSC, pre compression parameters, post compression parameters, in vitro drug release study and scanning electron microscopy study. The optimized formulation RM5 showed 94.83% at the end of 14 hrs with zero order drug release. The difference factor (f1) and similarity factor (f2) for RM5 were observed 14.61 and 75.12 respectively. Optimized formulation did not show any significant change on the pH and agitation intensity, but it depends on osmotic pressure of dissolution media indicated that mechanism of drug release was due to osmotic pressure. SEM micrographs confirmed that no pores were found before dissolution and after dissolution had shown the porous nature of the membrane. Short term stability study at 40±2oC/75±5% RH for three months on the RM5 formulation indicated that there was no significant change weight variation, % friability, drug content and in vitro drug release.