Formulation and Evaluation of Solid Dispersion of Atorvastatin Calcium

The present study was designed to improve the solubility and hence enhance the dissolution of hydrophobic drug Atorvastatin calcium (ATC) in order to increase its bioavailability. Solid dispersion of atorvastatin calcium using carrier PEG 4000 was formulated in different ratios by conventional fusion and microwave induced fusion method. In particular, the Microwave technology has been considered in order to prepare an enhanced release dosage form for poorly water soluble drug ATC. Their physicochemical characteristics and dissolution properties were compared to the corresponding dispersions and pure drug. Three different formulations were prepared using Conventional fusion method and Microwave induced fusion method in different ratios i.e., 1:1, 1:2, 1:3 and 1:1, 1:2, 1:3 respectively, were further characterized by FTIR, DSC and SEM analysis. The results of FTIR revealed that no chemical interaction between the drug and the polymer exist. DSC studies showed that the drug was in amorphous state completely entrapped by the polymer. SEM studies showed the surface morphology of the solid dispersion. All the formulations showed a marked increase in drug release with the increase in the concentration of PEG 4000 when tested for their in vitro studies. Formulation T5 showed the best release with a cumulative release of 86.15 % in 30 minutes, when compared to the pure drug and marketed formulation. The microwave assisted method was found to be better than conventional fusion method for preparation of solid dispersion.