GB752669A - Improvements in or relating to the preparation of insulin - Google Patents

Abstract

Insulin is recovered from an aqueous solution containing siliceous impurities by adjusting the pH of the solution to between 6,5 and 9,0, preferably 7,5 and 8,5 e.g. with 6N sulphuric acid, and precipitating the impurities as a flocculant precipitate. Pancreas glands are extracted with a 50 to 85 per cent aqueous solution of an organic solvent e.g. ethanol, methanol, acetone, at a pH below 4 e.g. using hydrochloric, sulphuric or phosphoric acid, and the extract is treated with a siliceous adsorbent e.g. clay, Fuller's earth, kaolin, kieselguhr, diatomaceous earth, bentonite, montmorillonite and "Super Filtrol" (Registered Trade Mark) which may be in the form of a packed body, at a pH of 2 to 4, to adsorb the insulin. The insulin is subsequently eluted by contacting the adsorbent with an aqueous eluent at a pH of from 9, to 13, preferably from 10 to 11,5 e.g. using ammonium hydroxide, trisodium phosphate buffer, alkali or alkaline-earth metal hydroxide. The siliceous impurities are precipitated from the eluate, and the separated supernatent liquid further processed to recover the insulin e.g. by adjusting the pH to approximately 2 and salting out with sodium chloride. The adsorbent may be washed with a non-insulin-eluting solvent e.g. methyl ethylketone, 95 per cent 3A alcohol, prior to the elution.