The invention relates to a
crystallization method for preparing high-purity monodisperse I
crystal form
atorvastatin calcium in a single kettle. The method is as follows: adding a mixed
solvent consisting of a good
solvent and an antisolvent of
atorvastatin calcium into a crystallizer, adding crystalline
powder of
crystal form I
atorvastatin calcium into the crystallizer, keeping the temperature of the solution at normal temperature, dispersing
crystal particles by using
ultrasound, and then raising the temperature to the temperature of the
dissolution process; adding two solutions of the anti-
solvent and the good solvent for dissolving the
atorvastatin calcium into
seed crystal suspension at the same time, and keeping the
solvent composition in the
seed crystal suspension in the process basically unchanged; adding the antisolvent into the crystallizer continuously, and then keeping temperature and suspending; reducing the temperature of the solution to normal temperature, and then filtering the solution, washing by pure water and
drying to obtain crystal the form I crystalline
atorvastatin calcium powder. The crystal particles of the
powder are long rod-shaped, and the longitudinal dimension of the powder is not more than 30mu m, and the cross-sectional dimension is not more than 5mu m. The
production cycle is short, the cost of the solvent is low, the operation is simple, andthe method is suitable for industrial production.