US Patent 7473366 Process for the purification of macrolides

The invention relates to a process for the recovery of a macrolide in substantial pure form including:a) treating an impure or crude macrolide with water immiscible solvent to form a mixture,b) optionally concentrating the mixture,c) treating with ammonia gas to phase out impurities,d) separating impurities,e) optionally concentrating a phase containing the macrolide,f) loading on silica gel chromatography, optionally reversed phase or pretreated with silver, and eluting the macrolide,g) affording the macrolide in the substantially pure form,h) optional repetition of steps f and g to afford the macrolide in the substantially pure form. The macrolide is preferably tacrolimus, immunomycin or sirolimus.