Formulation and evaluation of sustained release tablets of ramipril

The present study was aimed to formulate and evaluate sustained release tablets for ramipril employing xanthan gum, and to investigate its in vitro and in vivo performance using rabbit as animal model. Sustained release tablets of ramipril were prepared by direct compression technique. The tablets were evaluated for official pharmaco-technical parameters. Bioavailability parameter was undertaken using rabbits to assess the in vivo performance compared with in-house developed conventional formulation. The developed sustained release tablets of ramipril complied with the official tests. The batch prepared using 40 %w/w of xanthan gum exhibited drug release for 24 h in a sustained manner. The drug release from the tablets obeyed non-fickian diffusion and the order of release found to be first order kinetics. The in vivo studies demonstrated that a higher extent of absorption of drug was observed from the sustained release tablet owing to its lower elimination rate and prolonged half-life over developed immediate release tablets. Xanthan gum based matrix formulations exhibited sustained release for a period of 24 h. The sustained release tablets of ramipril were well absorbed and showed a higher extent of absorption over developed IR tablets. Our results suggest that sustained release tablets of ramipril are an efficient drug delivery system, which will over circumvent the problems in conventional therapy.