GB667275A - Improvements in or relating to the manufacture of crystalline potassium penicillin - Google Patents

Abstract

Crystalline potassium penicillin is produced by treating an aqueous n-butanol solution of potassium penicillin, of a purity of at least 800 (preferably 1000) u./mg., with activated carbon in amount not exceeding 10 per cent (e.g. 4 per cent) by weight of the solution, separating off the carbon, adjusting the pH of the solution, if necessary, to 5.0-7.5, preferably 6.4-6.6 (by addition of an alkaline potassium compound), evaporating the solution by more than one pass through a film evaporator, the water content of the solution being maintained at a value of at least 5 (preferably 20) per cent by volume until the penicillin concentration of the solution is at least 15 (preferably 20-35) mg./ml., and then continuing the evaporation (preferably by one or more further passes through the film evaporator) without further addition of water, until crystallization takes place. The product may be recrystallized, e.g. by dissolving in aqueous n-butanol and then adding dry n-butanol (preferably in two or more stages at 0 DEG C.) to bring the n-butanol concentration to about 95-99 (but preferably not above 97) per cent by volume. The mother liquors from the first crystallization may be worked up to obtain a further amount of potassium penicillin (mainly F), whilst those from the recrystallization may be recycled to an earlier stage of the process. A detailed example is given. Specification 658,415 is referred to. Specification 649,743 also is referred to in the Provisional Specification.