Water Solubility Enhancement of Atorvastatin by Solid Dispersion Method

Atorvastatin is currently used as calcium salt for the treatment of hypercholesterolemia. It is insoluble in aqueous solution of pH 4 and below; it is very slightly soluble in water and pH 7.4 phosphate buffer. In the present study, an attempt was made to enhance the solubility and dissolution characteristics of atorvastatin calcium using solvent evaporation method. HPMC was used as the polymer in different drug to polymer ratios. From the study it was found that HPMC at a drug to polymer ratio of 2:1 improves the water solubility of the drug by 2 folds when prepared as solid dispersions by solvent evaporation method.