Patent ID: 7645876

Claim:
A process for crystallizing a macrolide comprising: crystallizing a macrolide from a first solvent, a small amount of a second polar organic solvent, and an antisolvent, wherein the first solvent is selected from the group consisting of ethyl acetate, methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, tert-butanol, 2-butanol, acetone, acetonitrile, tetrahydrofuran, isobutyl acetate, n-butyl acetate, ethylformate, n-propyl acetate, iso-propyl acetate, methyl-ethyl ketone, and mixtures thereof, wherein the second polar organic solvent is selected from the group consisting of N,N-dimethylformamide, dimethylsulfoxide, dimethyl acetamide, N,N-diethylformamide, and mixtures thereof, and wherein the macrolide is selected from the group consisting of tacrolimus, ascomycin, and pimecrolimus.