A process for the preparation of the crystalline compound 4 '-deoxy-4' -epimethylamino-avermectin B1a / B1b benzoic acid salt hemihydrate (type B) useful as a medicament

摘要

The most thermodynamically stable crystalline form of the benzoic acid salt of 4"-deoxy-4"-epi-methylamino avermectin B1a/B1b as the hemihydrate is obtained by crystallization from organic solvents containing a controlled amount of water.