Poor water solubility and slow dissolution rate are issues for the majority of upcoming and existing biologically active compounds. Simvastatin is poorly water-soluble drug and its bioavailability is very low from its crystalline form. The purpose of the present investigation was to increase the solubility and dissolution rate of simvastatin by the preparation of nanosuspension by nanoprecipitation technique at laboratory scale. Prepared nanosuspension was evaluated for its particle size and in vitro dissolution study and characterized by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). A 23 factorial design was employed to study the effect of independent variables, amount of PVPK- 30 (X1), amount of SLS (X2) and organic to aqueous solvent ratio (X3) on dependent variables, particle size (nm) and time required to release 80% of drug (t80). The relationship between the dependent and independent variables was further elucidated using multiple liner regression analysis (MLRA). The obtained results showed that particle size (nm) and rate of dissolution has been improved when nanosuspension prepared with the higher concentration of PVPK-30 with the higher concentration of SLS and lower concentration of organic to aqueous ratio, The rate of dissolution of the optimized nanosuspension was enhanced (80% in 20min), relative to micronized suspension of simvastatin (7.03% in 20 min), mainly due to the formation of nanosized particles. These results indicate the suitability of 23 factorial design for preparation of simvastatin loaded nanosuspension significantly improved in vitro dissolution rate, and thus possibly enhance fast onset of therapeutic drug effect.
