Atorvastatin calcium (ATC) is a selective competitive inhibitor of HMG CoA reductase. However its absolute bioavailability is 14%, to increase the solubility and dissolution of hydrophobic drug (ATC) and to enhance the bioavailability of drug solid dispersion was prepared. Solid dispersion preliminary solubility analysis was carried out for the selection of carriers and solid dispersion was prepared with Soluplus, Kolliwax GMS II, Kolliphor P188, Kleptose HPB and PVPK-30 in proportions 1:1 and 1:3 besides SLS as surfactant (0 or 2%) to improving its aqueous solubility and rate of dissolution by solvent evaporation technique. All the formulations showed marked improvement in the solubility behavior and improved drug release. From all the formulations we demonstrated that Kolliwax GMS increases the aqueous solubility of Atorvastatin calcium and hence SD20 was found to be optimized formulation. The optimized formulation SD20 was characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction (XRD) to ascertain if there were any physicochemical interactions between drug and carrier that could affect dissolution and the change in the nature of the compound. The results obtained showed that the aqueous solubility and rate of dissolution was significantly improved when formulated in solid dispersion as compare to pure drug.
