GB790521A - Improvements in or relating to antibiotics - Google Patents

Abstract

<PICT:0790521/IV (b)/1> A new antibiotic Thiactin is produced by cultivating a thiactin-producing strain of Streptomyces hawaiiensis especially S. hawaiiensis ATCC 12236 in an aqueous nutrient medium containing a source of carbohydrate, nitrogen, growth substances and mineral salts under submerged aerobic conditions at a temperature of 24 DEG to 30 DEG C. for 3 to 5 days. The initial pH of the medium is 6.0 to 6.2. Specified carbon sources are starch, sucrose, glucose, maltose, dextrose, glycerol, galactose, xylose, arabinose, rhamnose, fructose, lactose, insulin and dextrin. Specified nitrogen sources are amino acids, casein, fish meal, soybean meal, meat extracts, liver cake, urea, nitrates, ammonium compounds, distillers' grain slop, corn steep liquor, wheat steep liquor, whey, acid hydrolysed corn (or wheat) gluten, peptone, brewers' yeast, cottonseed meal, lactalbumin tryptone and offals Specified mineral salts are sodium chloride, potassium phosphate, magnesium sulphate, sodium nitrate and trace metals. A buffer such as calcium carbonate may be present. Thiactin is recovered from the clarified broth by solvent extraction and adsorption. The extraction is by means of a water-immiscible organic solvent such as butanol, chloroform or methyl isobutyl ketone. The extract is concentrated and the thiactin recovered by the addition of an alkane or by lyophilization. The crude thiactin is dissolved in a solvent used as chloroform and adsorbed on a chromatographic adsorbent such as alumina, charcoal or silica, followed by elution with e.g. methanol in chloroform. Salts of thiactin with mineral acids such as hydrochloric, phosphoric and sulphuric or organic acids such as hydrochloric, phosphoric and sulphuric or organic acids such as citric, tartaric and gluconic are prepared by adding the desired acid to an aqueous solution of thiactin. Alkali metal salts of thiactin are prepared by treating an aqueous suspension of the antibiotic with an alkali metal hydroxide. Thiactin is soluble in formamide, chloroform, 2-methoxy ethanol, butanol, dioxane, amyl alcohol; less soluble in acetone, benzene, ethyl acetate, dimethoxyethane, dimethoxy diethylene glycol and ethanol. Melts at 226-235 DEG C. Contains only the elements carbon, hydrogen, oxygen, nitrogen and sulphur and has a typical analysis of N = 15.3 to 18.1 per cent, C = 51.7 to 52.2 per cent, H = 5.56 to 5.66 per cent and S = 9.2 to 10.1 per cent. It exhibits characteristic adsorption bands in infra-red region of the spectrum when pelleted in potassium bromide at the following wavelengths expressed in microns: 2.98, 3.37; 4.20-4.28 (broad band); 6.05; 6.50-6.70 (broad band); 7.00-7.10 (shoulder) 7.25; 7.70-7.95 (broad band); 8.28; 8.85-8.98 (broad band); 9.17; 9.25-9.50 (shoulder); 9.65-9.85 (shoulder); 10.15-10.35 (broad band); 10.75; 11.23 and 12.40-12.60 (shoulder); specific rotation in chloroform of [a ]27D = - 69. On acid hydrolysis yields a mixture of amino acids comprising a -alanine, threonine, glycine, leucine and cysteine or cystine. The Rf value in (a) water is 1,2; (b) 10 per cent aqueous sodium citrate is 1; (c) butanol saturated with water is 8, 9 and 10; (d) dry methyl isobutyl ketone is 1-4; (e) butanol saturated with water containing 2 per cent p. toluene sulphonic acid is 10. Rf values in other solvent systems are also given. Thiactin is active against gram positive bacteria and mycobacteria. It is incorporated in therapeutic compositions (see Group VI).ALSO:The antibiotic thiactin (see Group IV (b)) is employed in non-toxic amounts in therapeutic compositions in admixture with a compatible carrier or diluent.