Preparation and evaluation of captopril loaded gastro-retentive zein based porous floating tablets

In this study, gastro-retentive porous floating tablets of captopril based on zein are reported using l-menthol as a porogen. Tablets were prepared by the direct compression method. Removing of l-menthol through sublimation process generated pores in tablets, which decreased the density to promote floating over gastric fluid. Prepared tablets showed no floating lag time and prolong total floating time (>24 h). Drug release was found dependent upon porosity of tablets, an increase in porosity of tablets resulted in increased drug release, so it can be tuned by varying concentration of l-menthol. In addition to floating and sustained release properties, porous tablets showed robust mechanical behavior in wet conditions, which can enable them to withstand real gastric environment stress. In vivo studies using New Zealand rabbits also confirmed the prolonged gastric retention (24 h) and plasma drug concentration-time profile showed sustained release of captopril with higher T_max and MRT as compared to marketed immediate-release tablets. Overall, it was concluded that effective gastric retention can be achieved using porous zein tablets using l-menthol as a porogen.