GB1217303A - Improved water-soluble tetracycline complex - Google Patents

Abstract

1,217,303. Water-soluble tetracycline complexes. I. MARCUS. 12 June, 1967, No. 29967/69. Heading C2A. A novel water-soluble complex of a tetracycline and methyleneamino-salicylic acid or a salt thereof, is prepared by reacting in a solvent a tetracycline with the said acid or its salt. The complexes are said to be simple addition compounds; in the case of tetracycline itself the complex has the formula The preferred salt is that of sodium, and the reaction is suitably carried out in methanol, under an inert atmosphere (e.g. nitrogen) in the absence of light. The complex separates as a precipitate which is filtered off, washed with methanol and dried. The product is anhydrous and may be hydrated by allowing it to stand in moist air. The complex is unstable in aqueous solutions, but its stability is increased by increasing the concentration of the solution. The complexes react with streptomycin, neomycin or dihydrostreptomycin in solution (e.g. in ethanol) to liberate the tetracycline and form a corresponding addition compound with the reacting antibiotic. Pharmaceutical compositions having antibiotic activity comprise the tetracyclinemethyleneamino-salicylic acid complex or its physiologically acceptable salt together with a pharmaceutical carrier or diluent; the compositions may be in forms suitable for parenteral, oral or rectal administration.