Patent GB-868972-A (GB)
Title: A new antibiotic designated a 7907 and processes for its manufacture
Filed: 1957-06-14
Abstract: <FORM:0868972/IV (b)/1> A new antibiotic, designated A7909, is produced by cultivating Streptomyces A7909 nov. spec., or a mutant thereof, in an aqueous nutrient medium containing a source of carbon, nitrogen and inorganic salts under aerobic conditions.  Specified carbon sources are glucose, saccharose, lactose, starch and glycerol; nitrogen sources (including growth-promoting substances) are amino acids, peptides, proteins, peptone, tryptone, meat extracts, water soluble extracts of cereal grains, distillers residues, soyabeans, cottonseeds and nitrate, e.g. sodium nitrate. Inorganic salts are chlorides, carbonates or sulphates of alkali metals, alkaline earth metals, magnesium, iron, zinc or manganese; potassium phosphate. Calcium carbonate may be added as a buffer. Cultivation is at 18 to 40 DEG C., and preferably 27 DEG C. for 36-120 hours.  A7909 is recovered from the clarified broth by adsorption on (a) active carbon at pH7,5-8.0 or (b) a cation exchange resin having carbonyl groups, e.g. "Amberlite" (Registered Trade Mark) IRC-50.  Elution from carbon is by aqueous acid preferably of pH below 4 or by acid-containing solvents miscible with water, e.g. alcohols such as methanol or ketones, a mixture of methanol and N-formic acid being preferred. Prior to elution, the adsorbate is washed with an organic solvent miscible with water in order to remove impurities.  The eluate is concentrated, freed from calcium ions by the addition of oxalic acid, and further concentrated to recover the antibiotic.  Alternatively, the antibiotic is recovered by diluting the concentrate with methanol and adding acetone.  The broth may be clarified by adjusting to pH5, adding 0,5% aluminium sulphate and filtering.  In the case of adsorption on cation exchangers, the adsorbate is washed with water to remove inactive material and is then eluted with dilute aqueous acid, e.g. hydrochloric acid.  Further purification is obtained by forming a water-insoluble salt with (a) sodium-41-dimethylamino azobenzene-4-sulphonate (helianthin) or other azodyestuff containing sulphonic acid groups (b) picric acid (c)2,4-di-hydroxy-1,3,5-trinitrobenzene (styphnic acid) or (d) picrolonic acid.  In the case of (a), helianthin is added to an aqueous solution of the antibiotic at pH 6,5 to 7,0.  The helianthate is treated with a salt of an inorganic or organic acid with an organic base, e.g. triethylamine sulphate in an aqueous or alcoholic medium in order to recover the antibiotic salt of said acid, e.g., sulphate.  A7907 hydrochloride is produced by treating (a) A7907 sulphate with barium chloride in aqueous solution, or (b) A7907 helianthate with hydrogen chloride or hydrochloric acid in methanol. Other salts specified are the reineckate, the 4-nitro-barbiturate, acetate, palmitate, succinate, citrate and pantothenate.  The free base is obtained from (a) the sulphate by adding barium hydroxide to an aqueous solution of the sulphate and neutralising excess barium hydroxide with carbon-dioxide (b) its salts by treatment with a strongly basic anion exchanger on the OH cycle.  Antibiotic A7907 is soluble in water; insoluble in most organic solvents; it is basic forming salts with inorganic and organic acids (see above); it is a polypeptide and is active against both gram-negative and gram-positive bacteria; consists of four closely related compounds; the hydrochloride has a m.p. 188-190 DEG C., an elementary analysis of C=39,5%, H=7,2%, N=15,5%, O=20,6% and Cl=17,2%, a specific rotation of [a ]2d0=+21 DEG  (C=0,8 in water) and an infra red spectrum of 3,0, 3,45, 4,95, 5,85, 6,05, 6,40, 6,87, 7,28, 7,65, 8,10, 8,90 and 9.37 microns (the Figure).ALSO:A new antibiotic designated A7909, or a salt thereof (see Group IV (b)), active against a wide range of micro-organisms, is admixed with an organic or inorganic pharmaceutical carrier for enteral, parenteral or local administration.  The preparations may be in the form of tablets, dragees, powders, salves, creams, suppositories, solutions, suspensions or emulsions.  Optional ingredients are preservatives, stabilizers, emulsifiers, wetting agents, and other drugs.  Specified carriers are gelatin, lactose, starch, magnesium stearate, talc, vegetable oils, benzyl alcohols, gums, polyalkylene glycols, white petroleum jelly and cholesterol.  Specified salts of antibiotic A7909 are the sulphate, hydrochloride, acetate, palmitate, succinate, citrate and pantothenate.