GB1240941A - New antibiotic and its preparation - Google Patents

Abstract

1,240,941. Antibiotic 18,887 R.P. RHONE POULENC S.A. 22 Aug., 1969 [23 Aug., 1968], No. 42049/69. Heading C2A. Antibiotic 18,887 R.P., which is a white powder melting at 215‹ C., insoluble in hexane, sparingly soluble in ethyl acetate and water, easily soluble in aqueous butanol, being an acid with an acid equivalent of 475Œ25, a pK of about 5 in ethanol-water, having the elementary composition C, 54À3-54À7%; H, 7À2- 7À5%; N, 12À35-12À45%; and O, 23À4%; an optical rotation of [α]<SP>20</SP>D =-21‹Œ1‹ (C= 1, water) and [α]<SP>20</SP> D =0‹Œ1‹ (C = 0À5, chloroform) and a I.R. spectrum as shown in Fig. 2, is prepared by aerobically cultivating Streptomyces caelicus, strain DS 10,579 (NRRL 3506), or a 18,887 R.P.-producing mutant thereof, in an aqueous nutrient medium containing assimilable sources of carbon, nitrogen and inorganic salts, and separating the 18,887 R.P. formed. Preferably the culture is effected under submerged aerobic conditions at pH 6À0 to 7À8, at 23‹ to 33‹ C. the medium being aerated at 0À3 to 3 litres of air per litre of medium per minute. 18,887 R.P. may be separated from the culture medium by extraction with a water-immiscible solvent such as an aliphatic alcohol having at least 4 carbon atoms, e.g. butanol, preferably with the culture medium at pH 7, concentration of the organic solution under reduced pressure and precipitation of the antibiotic by addition of a non-solvent or poor solvent, e.g. hexane. The crude 18,887 R.P. may be further purified by recrystallization, chromatography on various adsorbents (e.g. ion exchange resins and activated charcoal) and/or countercurrent distribution. 18,887 R.P. may be converted into salts such as those of alkali metals and in particular the sodium salt. The antibiotic and its non-toxic salts may be used in pharmaceutical compositions in association with a pharmaceutically acceptable carrier and/or another therapeutically active substance, e.g. another antibiotic.