ABSTRACT:
The present study in the development of Hydrodynamically Balanced Systems (HBS) of Simvastatin an hypolipidemic drug which are designed to increase the gastric residence time, thus prolonging the drug release. Hydroxy propyl methyl cellulose (HPMC) of different viscosity grades at three different drugs to polymer ratios were used to prepare HBS by direct compression technique. The prepared HBS tablets were evaluated in terms of their pre-compression parameters, post-compression parameters and short term stability studies. The drug polymer ratio, viscosity grades of HPMC, different diluents and gas generating agents were found to influence the drug release and floating properties of the prepared HBS. The floating properties and drug release characteristics were determined for the prepared HBS in 0.1 N HCl dissolution media. All the HBS formulations showed good invitro floating properties with an optimum concentration of gas generating agents sodium bicarbonate and citric acid. The rate of drug release decreased with increased polymer concentration. It was found that HPMC viscosity had significant impact on the drug release from the prepared HBS. Among the three viscosity grades of HPMC (K4M, K15M, K100M), HPMC K4M along with lactose as diluents was found to be beneficial in improving the drug release rate and floating properties The short term stability study indicated that there was no much differences observed.