ASCOMYCIN AND PIMECROLIMUS HAVING REDUCED LEVELS OF DESMETHYLASCOMYCIN AND 32-DEOXY-32-EPICHLORO-DESMETHYLASCOMYCIN RESPECTIVELY, AND METHODS FOR PREPARATION THEREOF

摘要

Provided is ascomycin that has a low level of an FK523 impurity, and pimecrolimus that has a low level of a 32-deoxy-32-epichloro-FK523 impurity, methods of preparing them, and the use of such pimecrolimus for preparing a pharmaceutical composition.