Objective: The poor solubility which causes the poor bioavailability of simvastatin is an arduous task for the preparation of oral dosage form, which can be increased by the preparation of solid dispersion. Materials and Methods: The solid dispersions of simvastatin were prepared in different ratios by physical mixture method, kneading method and melting method using PEG 6000, β-cyclodextrin and Hydroxy Propyl β-cyclodextrin to enhance the solubility of poorly soluble drug. Results: These solid dispersions were analyzed for the solubility by prescribed methods. The solid dispersion of drug with HP β-cyclodextrin in 1:1 ratio has shown enormously improved solubility. Further FTIR and X-Ray studies were carried out. The compatibility study showed that there is no interaction between the drug and HP β-cyclodextrin and PXRD confirmed the amorphization of crystalline drug. Conclusion: The overall result showed that the solid dispersion of simvastatin can be prepared by various methods, of which the kneading method was best with HP β-CD in 1:1 (drug: polymer) ratio, in comparison with melting and physical mixture method. Hence we can conclude that the solubility of simvastatin can be enhanced using HP β-CD.
Key words: Solid dispersion, HP β-cyclodextrin, PXRD, HMG Co A reductase, Complexation.