Supercritical Co <sub> 2 </ Sub> Preparation Of Nimodipine Solid Dispersions

Nimodipine solid dispersion was prepared by supercritical CO₂ method to improve the dissolution and bioavailability of nimodipine that is poorly water soluble.Methods of content assay and in-vitro release test (UV spectrophotography) and relative substances detection (HPLC) were respectively carried out. All methods had good linearity, sufficient recovery and good accuracy. The RSD of intraday and interday precision are lower than 2%Using dissolution in vitro of nimodipine as index, orthogonal experiment was done based on single factor experiments and the optimal conditions were: PVPK30 was the carrier material, the proportion of nimodipine and PVPK30 was 1:8, supercritical experiment time was 7h, temperature 55℃, pressure 25MPa. Dissolution in vitro of solid dispersion prepared indicated that accumulating dissolution in 60min was 97.66% and 74.67% prepared by solvent evaporation method. Nimodipine was in amorphous phase or dispersed in molecules, indicated by differential scanning calorimeter (DSC).The solid dispersion prepared in optimal condition was encapsulated and fast release capsule was obtained. Dissolution in vitro of the capsule and nimodipine tablet saled showed that dissolution rate of the capsule was 93.12%, better than tablet saled which dissolution rate was 70.61%.