Microparticulated anti-HIV vaginal gel: In vitro-in vivo drug release and vaginal irritation study

The aim of this study was to develop and evaluate a Zidovudine (AZT)-loaded microparticulated bioadhesive vaginal gel (MBVG) in order to obtain a controlled releasing, safe gel delivery system. AZT microparticles (ZMPs) were evaluated for encapsulation efficiency, drug loading, surface morphology and in vitro drug release profiles and drug release mechanism and optimized. The optimized ZMPs were then encompassed in bioadhesive gel using different bioadhesive polymers and evaluated for the drug encapsulation efficiency, drug loading, in vitro and in vivo drug release profiles, drug release mechanism and vaginal irritancy study. From the dissolution data of ZMP4 and MBVG4 showed a zero-order diffusion pattern and Fickian diffusion case I transport mechanism in 24 and 36 h, respectively. On the basis of a pharmacokinetic study of MBVG4 (containing ZMP: Carbopol 1:4), it was found to have better bioavailability, larger AUC and T-max in comparison to an oral pure suspension of AZT.