GB879629A — Improvements in or relating to stable 6-demethyl-tetracycline antibiotic compositions

USPTO Abstract

A tetracycline antibiotic is solubilised in aqueous solution according to the parent Specification, but is characterised in that the tetracycline antibiotic is a 6-demethyl tetracycline or a soluble salt thereof. Specified are 6-demethyl tetracycline, 6-demethyl-6-deoxytetracycline and 7-chloro-6-demethyltetracycline. In accordance with the said parent Specification, the 6-demethyl tetracycline is solubilised by addition of a soluble non-toxic source of alkaline earth ions and a pyridine derivative having the formula:- <FORM:0879629/IV (b)/1> wherein R is hydrogen or a N-alkylcarbamyl, N-alkanolcarbamyl, hydrazinocarbonyl, hydroxyl, hydroxyalkyl, alkoxycarbonyl or carboxyl radical or a salt of a carboxyl group with a non-toxic metal; R1 is a hydrogen or methyl group and R11 and R111 are each hydrogen or a hydroxymethyl group.ALSO:A tetracycline antibiotic composition of enhanced solubility and stability according to the parent Specification is characterized in that the tetracycline antibiotic is a 6-demethyl tetracycline or a soluble salt thereof. Specified are 6-demethyl tetracycline, 6-demethyl-6-deoxytetracycline and 7-chloro-6-demethyl tetracycline. In accordance with the said parent Specification the 6-demethyl tetracycline is mixed with a soluble non-toxic source of alkaline earth ions and a pyridine derivative having the formula <FORM:0879629/VI/1> wherein R is hydrogen or a N-alkylcarbamyl, N - alkanolcarbamyl, hydrazinocarbonyl, hydroxyl, hydroxyalkyl alkoxy carbonyl or carboxyl radical or a salt of a carboxyl group with a non-toxic metal; R1 is hydrogen or a methyl group and R11 and R111 are each hydrogen or a hydroxy methyl group. In an example, an aqueous solution of pH 3.3 to 4 is prepared by dissolving 7 - chloro - 6 - demethyltetracycline hydrochloride, magnesium gluconate, nicotinamide, citric acid an xylocaine base in water.