Development and in-vitro evaluation of modified release tablets including ethylcellulose microspheres loaded with diltiazem hydrochloride

摘要

In this study,development of modified release tablet formulations containing diltiazem hydrochloride-loaded microspheres to be taken once rather than two or three times a day was attempted.For this purpose,ethylcellulose microspheres were prepared by emulsion-solvent evaporation technique.The influence of emulsifier type and drug/polymer ratio on production yield,encapsulation efficiency,particle size,surface morphology and in-vitro release characteristics of the microspheres was evaluated.Suitable microspheres were selected and tabletted using different tabletting agents,Ludipress~R,Cellactose~R 80,Flow-Lac~R 100 and excipients Compritol~R 888 ATO,Kollidon~R SR.Tablets were evaluated from the perspective of physical and in-vitro drug release characteristics.It was seen that type and ratio of the excipients played an important role in the tabletting of the microspheres.As a result,two tablet formulations containing 180mg diltiazem hydrochloride and using either Compritol~R 888 ATO or Kollidon~R SR were designed successfully and maintained drug release for 24 h with zero order and Higuchi kinetics,respectively.