GB948090A — Improvements in or relating to tetracycline complexes

USPTO Abstract

The invention relates to complexes of 6-demethyl tetracycline or 7-chloro- -6-demethyl tetracycline, aluminium, a cation selected from the cations of hydrogen, calcium and magnesium, and gluconic acid in the molar ratio of antibiotic to aluminium to cation to acid of not less than 1:1:1:1 and not greater than 1:6:9:28 save that when the cation is hydrogen the ratio of antibiotic to cation may be 1:28. These complexes are prepared by reacting the antibiotic or a salt thereof, an aluminium compound which furnishes aluminium ions in aqueous solution, gluconic acid or glucono-delta-lactone and, when the cation is not hydrogen, a calcium or magnesium compound which furnishes calcium or magnesium ions in aqueous solution so as to form said complex. Specified antibiotic salts are the hydrochloride, hydrobromide, nitrate, sulphate or an alkali or alkaline earth metal salt. The aluminium may be added as the ethoxide, isopropoxide, citrate, nitrate, lactrate, formate, chloride, sulphate or as potassium aluminium sulphate. The complex forming cations of calcium and magnesium may be added in the form of their oxides, hydroxides or water soluble salts. The complexes may be administered parenterally in aqueous solution.