GB630462A - Improvements in or relating to the preparation of salts of penicillin - Google Patents

Abstract

Salts of penicillin are manufactured by the action of a salt or salts of a suitable primary organic base or bases and a suitable organic acid or acids on penicillin dissolved in a suitable solvent or mixture of solvents, preferably containing a quantity of one or more suitable secondary solvents. Suitable primary organic bases are compounds of the general formula R.NH2, wherein R represents a hydrocarbon residue containing, in the case of an alkyl or alkenyl group, not more than 4 and in other cases not more than 8 carbon atoms, which compound has a PKH value of not less than 10.2, and, under the conditions of the process, does not rapidly destroy penicillin, e.g. cyclohexylamine, methylcyclohexylamines, ethylamine, isopropylamine and n-butylamine. Suitable organic acids are aliphatic or substituted aliphatic acids having not more than 8 carbon atoms in the straight chain, e.g. formic, acetic, propionic, butyric, isobutyric, caprylic, phenylacetic, glycollic and malonic acids. Suitable solvents are solvents into which penicillin can readily be extracted, which are relatively inert to penicillin, and in which the primary organic base salts of penicillin are relatively insoluble, e.g. amyl acetate (preferred), diethyl ether, butyl acetate and methyl isobutyl ketone. Suitable secondary solvents are solvents in which the primary organic base salts of penicillin are relatively insoluble but those of the impurities normally present are soluble, e.g. ethyl alcohol, preferably in the proportion of 2-10 per cent of the main solvent. The primary organic base salts may be converted into metallic (e.g. sodium or calcium) salts of penicillin. Examples describe the preparation of the cyclohexylamine salt of penicillin. Specifications 606,482, 610,731 and 622,988 are referred to. Samples have been furnished under Sect. 2 (5) of the ethylamine and isopropylamine salts of penicillin.