GB552619A - Improvements relating to bactericidal substances - Google Patents

Abstract

552,619. Bactericidal substances. BOOTS PURE DRUG CO., Ltd., COULTHARD, C. E., MICHAELIS, R., and SHORT, W. F. Oct. 14, 1941. No. 13242. [Class 81 (i)] A bacteriostatic substance, denoted in the Specification as penicillin A, is obtained from a culture on a suitable medium (e.g. a solution of glucose containing small proportions of sodium nitrates, potassium phosphate and chloride, magnesium sulphate and ferrous sulphate), of a strain of Penicillium notatum capable of maintaining an acid PH in a glucose medium during growth and of producing an active agent insoluble or slightly soluble in usual organic solvents. The strain of penicillin is selected by trial and error to obtain colonies having the stated growth characteristics and product. A culture medium as described above is inoculated with a selected strain grown for about 14 days on the same medium. The PH of the medium at the beginning of growth is about 6.5 and falls after 3-4 days to about 3.5 at which it remains until the completion of growth in about 8-14 days. The liquor, from which most of the glucose has disappeared, is decanted and filtered and may be stored with the addition of chloroform as a preservative. To isolate the active substance the liquor may be concentrated, by evaporation under reduced pressure, or by freezing out, and the substance precipitated with an organic solvent, preferably acetone. Purification is effected by solution in water and reprecipitation. Reference is made in the Specification to the literature including the Lancet 1941.2, page 177.