GB915839A - A new antibiotic a 9828 and process for its manufacture - Google Patents

Abstract

<PICT:0915839/IV (b)/1> A new antibiotic A9828 active against bacteria and influenza virus is produced by cultivating Streptomyces griseus strain A9828 (Zurich), or a mutant thereof, under surface or submerged aerobic conditions, in an aqueous nutrient solution containing a source of carbon, nitrogen and inorganic salts. The temperature is 19 DEG C. to 38 DEG C., and preferably 27 DEG C., and the duration 4 to 7 days. Suitable salts are the chlorides, nitrates, carbonates or sulphates of alkali metals, alkaline earth metals, magnesium, iron, zinc and manganese. Suitable N and C sources are amino-acids, peptides, proteins, hydrolysates of proteins e.g. peptone or tryptone, meat extracts, the water-soluble constituents of cereal grains, distillers solubles, glucose, saccharose, lactose and starch. The antibiotic is isolated by extracting the whole or clarified broth with a water-immiscible organic solvent such as ethyl acetate or petroleum ether. In the case of the clarified broth, the adsorbed antibiotic may be removed from the mycelium by extraction with an organic solvent at least partially-miscible with water e.g. acetone or butanol. Alternatively the antibiotic may be adsorbed on active carbon or an activated earth followed by elution with a solvent at least partially-miscible with water. Impurities may be removed by treatment with (a) aqueous acid of pH below 5 or (b) aqueous alkali of pH above 8. Further purification is obtained by (a) counter-current distribution between aqueous alcohol and a water-immiscible solvent e.g. petroleum ether/ethanol/water (5 : 4 : 1) or (b) chromatography on alumina. The antibiotic may be crystallised from pentane. Antibiotic A9828 melts at 65 to 67 DEG C.; [a ]20D = +5 DEG (C = 0.62 rectified spirits); contains 66.40% C, 9.09% H and 24.51% O; has molecular weight of 671 and formula C36H58O10; exhibits no maximum in the ultra-violet; exhibits in the infra-red spectrum in carbon tetrachloride bands at 5.77, 6.86, 7.28, 7.54, 7.95, 8.43, 8.57, 8.97 and 9.43 microns; it is neutral and contains no acylatable OH groups and no reactive keto groups; on hydrolysis with an alkali it yields two acids having Rf values of 0.32 and 0.50 when paper chromatographed on Whatman No. 1 paper impregnated with formamide and developed with chloroform saturated with formamide, the acid of Rf value 0.50 melting at 72 to 73 DEG C., having a specific rotation of [a ]20D = -2 DEG (C = 0.872 in chloroform), molecular weight 240 and formula C11H20O4 (C = 61.15%, H = 9.26% and O - 29.59%). Antibiotic A9828 is used in pharmaceutical compositions (see Group VI).ALSO:A pharmaceutical preparation for enteral, parenteral or topical administration comprises a carrier and antibiotic A9828 (see Group IV (b)) which is active against many bacteria and influenza virus. The antibiotic may be used in admixture with the acids obtained by the alkali hydrolysis of the antibiotic. The preparations may be used in the form of a tablet, dragee, powder, salve, cream, suppository, solution, suspension or emulsion. Preserving stabilizing, wetting and emulsifying agents may be present.