Preparation and examination of the release rate in-vitro for gel matrix sustained-release tablets of Simvastatin

Objective:To prepare gel matrix sustained-release tablets of Simvastatin with hydroxypropyl methyl cellulose(HPMC) as matrix material,and examine the impact of the preparation technology and the release conditions in-vitro on the release rates.Methods: The release rates in-vitro were analyzed by UV spectrophotometry.The release mechanism was discussed by Ritger-Peppas model.Results: The rotating speed of the dissolving apparatus was influenced on the release rate in-vitro,the release speed increased,with the increasing of the rotating speed,and the results also showed that the granulation methods,the tablet hardness,and the dissolving device did no obviously affect the release rate.The preparation technology had better productive reproducibility,the release rates were more than 80% after 12 h,and the release process was confirmed as the combination result of matrix erosion and drug diffusion.Conclusion: It is feasible that the release rates are analyzed by UV spectrophotometry.The preparation of sustained released tablets of Sismvastatin is slow,stably,and meets the prepared requirements.