Preparation of microsized atorvastatin calcium by antisolvent precipitation
The microsized atorvastatin calcium was prepared via the antisolvent precipitation process.The effects of the type of surfactants,drug concentration,precipitation temperature and drying method on particle morphology and particle size were investigated,and the optimum conditions were obtained.The as-prepared microsized atorvastatin calcium and the raw atorvastatin calcium were well characterized by scanning electron microscopy(SEM),powder X-ray diffraction(XRD),Fourier transform infrared spectrometry(FT-IR)and surface area analyzer.The results indicated that methyl cellulose(MC20)was a suitable surfactant to control the particle morphology of atorvastatin calcium.Adjusting drug concentration and system temperature can easily control the particle size and distribution.The spray dried powder with a mean diameter of about 1 μm had a narrow particle size distribution and showed the morphology of granular aggregates composed of smaller spheres.The microsized atorvastatin calcium powder was amorphous,and the specific surface area of the microsized product was higher than the raw atorvastatin calcium.In addition,the possible formation mechanism of granular aggregates composed of smaller spheres was presented.