GB746833A - Purification of penicillin - Google Patents

Abstract

Penicillin is purified by treating penicillin with dibenzylethylene diamine (or a salt of penicillin with a salt of dibenzylethylene diamine) in solution in a solvent in which dibenzyl-ethylene diamine penicillin is substantially insoluble, separating the precipitated dibenzylethylene diamine penicillin and suspending it in a mixture of water and a substantially water-immiscible organic solvent, and then hydrolysing the dibenzylethylene diamine penicillin (a) under acid conditions, the liberated penicillin being recovered from the organic solvent phase, or (b) under alkaline conditions at a temperature below room temperature, the formed salt of penicillin being recovered from the aqueous phase. It is preferred that 5 to 50 mil. water and 5 to 50 mil. organic solvent be used per gram of dibenzylethylene diamine penicillin, the water and solvent being in equal proportions. Water-immiscible organic solvents are aliphatic alcohols such as butanol and amyl alcohol; carboxylic acid esters such as butyl acetate and amyl acetate; ketones such as methyl isobutyl ketone; chlorinated aliphatic hydrocarbons such as chloroform; and ethers such as diethyl and diisopropyl ether. Acid hydrolysis is by any mineral or organic acid at a pH of 0.5 to 1.5, and preferably 1.0. The penicillin is recovered from the organic solvent phase after a preliminary treatment with active carbon by treatment with (a) an alkaline compound of an alkali or alkali earth metal or (b) an organic base, the penicillin salt of which is insoluble in the solvent, e.g. oxycaine, procaine and dibenzylethylene diamine. Alkaline hydrolysis is preferably by means of dilute aqueous alkali such as sodium hydroxide. Specification 716,556 is referred to.