GB779257A - Improvements in or relating to antibiotics and the preparation thereof - Google Patents

Abstract

<PICT:0779257/IV(b)/1> <PICT:0779257/IV(b)/2> A new antibiotic oleandomycin (originally referred to as PA 106 and also called amimycin) is produced by cultivating Streptomyces antibioticus ATCC 11891, or a mutant thereof, in an aqueous nutrient medium under submerged aerobic conditions until substantial anti-bacterial activity is imparted to the medium. A temperature of 24 DEG to 30 DEG C. and period of 1 to 4 days is suitable. The medium contains (a) a source of carbohydrate, e.g. sugars, starch, glycerol and corn meal; (b) a source of nitrogen, e.g. casein, soybean meal, peanut meal, wheat gluten, cottonseed meal, lactalbumin, enzymatic digest of casein and tryptone; (c) a source of growth substance, e.g. distillers' solubles, yeast extract and molasses fermentation residues; (d) mineral salts such as sodium chloride, potassium phosphate, sodium nitrate, magnesium sulphate; and (e) trace metals such as copper, zinc and iron. A buffer, e.g. calcium carbonate and anti-foaming agent, may be present. After removal of the mycelium a crude product is obtained by drying the residual broth. Oleandomycin is isolated from the liquid broth by (A) solvent extraction or (B) adsorption. Solvent extraction is at pH 6 to 10 by means of water-immiscible solvents such as diethyl ether, benzene, toluene, ethyl acetate, butyl acetate, methyl isobutyl ketone, butanol and chloroform. Purification is obtained by treating the extract with water of below pH 2.5 and re-extracting the solution with the organic solvent as pH 6 to 10. The anti-biotic may be recrystallized from ethyl acetate, chloroform methylene chloride or ethylene dichloride. Adsorption is on (a) charcoal, (b) ion-exchange resin, or (c) alumina. Oleandomycin is a basic white amorphous compound; effective in inhibiting the growth of gram-positive bacteria and mycobacteria; forms salts with acids such as hydrochloric, sulphuric and phosphoric acid; soluble in water, methyl alcohol, ethyl alcohol, acetone and butanol, insoluble in hexane, carbon tetrachloride and di-n-butyl ether; the crystalline hydrochloride (a) melts at 134 DEG to 135 DEG C.; (b) contains 57.63 per cent carbon, 8.73 per cent hydrogen, 1.87 per cent nitrogen, 4.30 per cent chlorine and 27.47 per cent oxygen, probably C35H67NO12.HCl; (c) exhibits a broad, low intensity peak in the ultra-violet region at 286-289 mm ; (d) suspended in a potassium bromide pellet shows peaks in the infra-red at the following frequencies: 3380, 2940, 2890, 1710, 1640, 1465, 1380, 1330, 1190, 1160, 1115, 1075, 1055, 1010, 985, 935, 865 and 828 cm-1, hydrochloride dissolved in methanol: <FORM:0779257/IV(b)/1> molecular weight of base is approximately 715; in chloroform the base exhibits characteristic absorption in infra-red at 3510, 2910, 2890, 2840, 2790, 1710, 1460, 1385, 1335, 1305, 1280, 1180, 1160, 1110, 1075, 1050, 1005, 985, 960, 935, 895, 885 and 886 cm.-1. Hydrochloride may be produced by passing hydrogen chloride gas into an acetone solution of the base.