GB720477A - Improvements in or relating to anti-virus agents, and the preparation thereof - Google Patents

Abstract

An antivirus agent is obtained by maintaining a solution of oxytetracycline under mildly alkaline conditions until substantial antivirus activity (test micro-organism influenza virus) is imparted to the solution. The solvent may be water, a water-miscible organic solvent, e.g. alcohol or a mixture thereof. A pH of 10 to 12 and a temperature of 20 DEG to 100 DEG C. is preferred. The higher the temperature, the shorter the digestion time. Thus at 20 DEG to 35 DEG C. the time is 2 to 10 days; at 90 DEG to 100 DEG C. the time is 1/2 to 3 hours. The lower temperature produces the most active product. The agent may be isolated from the solution by (a) freezy-drying or (b) acidifying to pH 2 to 4 and filtering off the separated solid. The original solution may be rendered alkaline by an organic or inorganic base, the alkali metal hydroxides being preferred. Any strong acid may be used in step (b); preferred are phosphoric, sulphuric or hydrochloric. The antivirus agent is active against the influenza A virus; has low solubility in dilute, aqueous acid; the acid form is soluble in acetone, methanol, butanol and pyridine, but insoluble in ether, chloroform, dioxane and acetonitrile; its activity against Klebsiella pneumoniae is preferably less than 10 per cent of that of oxytetracycline. The agent may be used therapeutically with other antibiotics (see Group VI).ALSO:A therapeutic preparation comprises a solution of an antivirus agent obtained by maintaining oxytetracycline under mildly alkaline conditions until substantial activity against the influenza A virus is obtained (see Group IV (b)]. Optional additions are penicillin, streptomycin, "Viomycin" (R.T.M.) or oxytetracyline.