| abstract |
The invention provides pure tacrolimus and a method for purifying tacrolimus in which a loading charge of tacrolimus is placed in juxtaposition with a bed of wet sorption resin, the loading charge and bed are eluted with an eluent comprising THF, acetonitrile, or a combination thereof, water, and, optionally, at least one additional organic solvent, the heart cut of the eluent is collected, and tacrolimus is collected, the tacrolimus is further crystallized and recrystallized until obtaining a reduced level of impurities. |