GB786635A - Method for the production of insulin with increased zinc content - Google Patents

Abstract

Crystalline or amorphous zinc insulin having a zinc content of 2.72 to 8.00 per cent by weight is prepared by reacting a suspension or solution of crystalline or amorphous insulin with a zinc compound in a liquid medium which does not take part in the reaction, which is a weak organic base, e.g. amines, amides, pyridines, a cresol, a phenol, an organic acid, a monovalent or polyvalent alcohol or a compound or derivative thereof, e.g. esters, ethers, ketones and halogen- or thio-derivatives of said substances, and which contains between 0 and 85 per cent by weight of water. The liquid medium may contain substances which prevent the precipitation of zinc hydroxide, e.g. ammonium chloride in ammonia solution, potassium or ammonium salts of ethylenediamine tetracetic acid, tri(acetic acid) amine, and aminoacetic acid. Specific liquid media disclosed are glacial acetic, lactic, glycollic, formic, and propionic acids, ethyl alcohol, anhydrous phenol, benzyl alcohol, glycol, glycerol, thiodiglycol, 3-chloro-1 : 2 - propanediol, 1 - phenol - 4 - sulphonic acid, methyl acetate, chloroacetic ethyl ester, acetone, aniline and pyridine. Specified zinc compounds are zinc chloride, sulphate or acetate or if the medium is acidic, zinc oxide or hydroxide. Injectable suspensions of zinc insulin may be prepared in water or resorbable organic liquids, e.g. vegetable or animal oils such as peanut oil, which may also contain sodium chloride and acetate, phenol and tricresol, and ions of at least one of the metals zinc, calcium or magnesium may also be added.