GB820535A - A new salt of phenoxymethyl-penicillin and its use for the isolation of said penicillin - Google Patents

Abstract

The invention relates to the phenoxymethylpenicillinate of N,N-di-isopropyl-beta-hydroxy-ethylamine. The salt is prepared by reacting the free base with the free acid in an organic solvent, or by reacting a salt of the base, e.g. the acetate, with a salt of the penicillin, e.g. potassium phenoxymethylpenicillin. The salt is sparingly soluble in organic solvents such as n-butyl acetate, n-amyl acetate, ethyl acetate, acetone, methyl ethyl ketone and ether. It is used in recovering phenoxymethylpenicillin from fermentation broths, the penicillin so recovered being substantially free from phenoxyacetic acid or beta-phenoxylactic acid (precursors used in the fermentation) and from benzyl penicillin. The broth is acidified to solubilize the phenoxymethyl penicillin, e.g. by the addition of phosphoric acid to pH 2.0, extracted with n-butyl acetate or other organic solvent sparingly soluble in water, N,N-diisopropyl - beta - hydroxyethylamine added to the extract and the phenoxymethylpenicillinate of N,N - diisopropyl - beta - hydroxy - ethylamine crystals filtered off, washed with acetone and dried. Alternatively, the organic solvent extract is treated with an aqueous buffer, e.g. aqueous sodium phosphate of pH 6.5, and the aqueous extract so obtained is then extracted with the organic solvent and the base added to that extract. The salt may be converted to other salts of phenoxymethylpenicillin; or may be converted to the free phenoxymethylpenicillin by treatment with strong acid in aqueous solution or suspension.