GB799903A - Dibenzylethylenediamine diphenoxymethyl-penicillin - Google Patents

Abstract

Needle-shaped crystals of dibenzylethylene-diamine diphenoxy methyl penicillin having at least 50 per cent of the crystals of length greater than two microns is obtained by precipitating the crystals from an aqueous solution thereof in the presence of an aliphatic alcohol or ketone. Specified are methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone and mixtures thereof. The crystals are formed by mixing an aqueous solution of a salt of dibenzylethylene diamine such as the acetate with an aqueous solution of an alkali metal salt of phenoxymethyl penicillin, either or both of which contain the alcohol or ketone, preferably in a concentration of 9 to 50 per cent of the final mixed solutions. It is preferred to heat the solutions above room temperature, e.g. up to 50 DEG C., especially 45 DEG C., prior to mixing, and to add the solution of dibenzylethylene diamine salt (1) slowly (10 to 15 minutes) with agitation to the solution of the penicillin salt, (2) the temperature being maintained at e.g. 45 DEG C. Alternatively, solutions (1) and (2) may be run slowly (2 hours) into a mixture of the alcohol or ketone and water, the penicillin salt being in excess until the end of the addition. The penicillin salt may be used orally (see Group VI).ALSO:Crystalline dibenzylethylenediamine diphenoxymethyl penicillin having at least 50 per cent of the crystals of length greater than two microns (see Group IV (b)) is employed in aqueous suspensions for oral use.