In-Vitro and In-Vivo Evaluation of Multi Unit Stavudine Gastroretentive Dosage Forms

GRDDSs helps in maintenance of constant therapeutic levels for prolonged periods and produce therapeutic efficacy and there by reduces the total dose of administration.GRDDSs are formulated as floating microparticles, tablets, pellets, capsules, etc among which the multiparticulate systems are more effective than the single unit dosage forms[1]. Assessment of dissolution study results revealed that formulations F7 (Stavudine: Gelucire 43/01- 1:1), F10 (Stavudine: Compritol 888 ATO - 1:1.5) and F19 (Stavudine: Lubritab - 1:2) had retarded the drug release in controlled manner upto 12 hours. The relative contributions of drug diffusion and matrix erosion to drug release were further confirmed by subjecting the dissolution data to Higuchi model and Erosion model. No prominent enthalpy changes was observed in the DSC thermograms of Stavudine+ Gelucire 43/01 physical mixtures and optimized formulations upon comparison with the peaks of drug and polymer alone. From the in vivo X-ray studies, conducted in the healthy human volunteers, it was found that the gastric residence time of the developed Stavudine multi unit granule system floating is dependent on the conditions of the stomach.