Tetracycline hydrochloride prodn - by pptn of crude tetracycline with acetate ester and methanol and rapid acidification with

摘要

Tetracycline (I) hydrochloride is produced from (I) with a purity of 3030-100% and a moisture content of =6% by dissolving (I) in a pptn. medium contg. a 2-5C alcohol ester of acetic acid and MeOH, adding a small excess of HCl and immediately evaporating in vacuo to remove MeOH and most of the H2O present in the system. The pharmaceutically acceptable crystalline form of (I). HCl may be obtained by carrying out evapn. in 2 stages, the first at 28 degrees C and the second at 45-48 degrees C.