Statistical Optimization and Development of Gastro Retentive System of an Antiretroviral Drug using a 32 Factorial Design

The goal of the present study was to develop a gastric floating drug delivery system (GFDDS) of Zidovudine (AZT), an antiretroviral drug. The tablets of AZT were prepared by direct compression technique using HPMC K15M as a polymer with other standard excipients. The mixture of sodium bicarbonate and citric acid was used as gas generating agent. Preliminary studies demonstrated that the, tablets remained buoyant for over 15 hr in the release 2 medium(pH 1.2). 3(2) factorial design was applied to systematically optimize the drug release profile. The proportion of retardant material HPMC K15 M (X-1) and gas generating agent (X-2) were selected as independent variables. The time required for 50% drug release t(50%) (Y-1) was selected as dependent variable. The optimization was carried out using softwares like statplus. The derived polynomial equations for t(50%) were verified by two check point formulations, which showed that factor X-1 and X-2 significantly affects the studied dependent variable. The non Fickian diffusion release transport was confirmed as the release mechanism for the optimized formulation. The predicated values agreed well with the experimental values and the results demonstrated feasibility of the model in the development of GFDDS.