INSULIN PRODUCT

1385086 Insulin complexes ELI LILLY & CO 28 April 1972 [30 April 1971] 19741/72 Heading A5B Insulin salt-protamine complexes containing an alkali metal e.g. sodium, potassium, lithium or caesium, or ammonium salt of insulin and from 0.2 mg to 1.5 mg of protamine for each 100 units of insulin have a rapid onset and a prolonged duration of hypoglycaemic action. A suspension of the complex in an aqueous medium e.g. water or an isotonic solution is prepared by combining in an aqueous medium protamine and an alkali metal or ammonium salt of insulin in proportions so that for each 100 units of insulin there is present from 0.2 to 1.5 mg of protamine. The insoluble complex may be separated from the aqueous medium and the moisture content thereof reduced to less than 10% by weight. The alkali metal salt of insulin may be prepared by subjecting crude insulin to treatment in the presence of alkali metal ions e.g. from an alkali metal hydroxide to effect crystallization of the salt.