Matrix Based Sustained Release Tablets of Carvedilol: Formulation and In-vitro Characterization

Background and Objective: The objective of the present investigation was to fabricate sustained release matrix tablets of carvedilol using different grades of HPMC and carbopol. Methods: Solid dispersion of carvedilol with PVP K30 was prepared using spray drying technique. This solid dispersion was incorporated into hydrophilic matrix of HPMC or carbopol in different ratios and directly compressed to get matrix tablets. The powder blend was characterized with bulk density, tapped density, Carr's compressibility index and Hausner ratio. Tablets were characterized for thickness, weight variation, hardness, drug content, in-vitro drug release and release mechanism. Results: Combination of HPMC K100M and HPMC K4M at concentration of 7.5% each in formulation could sustain the drug release for 18 h matching with marketed formulation and the drug release fitted to Higuchi's model for Fickian diffusion. Single grade of HPMC or carbopol or HPMC-carbopol combination did not match the target release profile. Flow property and compressibility of the powder blend was acceptable and suitable for direct compression process. Thickness, weight variation, hardness and drug content of the optimized tablet were well within the internationally accepted ranges. Conclusion: Combination of different grades of HPMC at appropriate ratios could match the release of carvedilol with the marketed product.