GB872214A - Extraction process for the recovery of heparin - Google Patents

Abstract

Heparin is recovered by extracting defatted animal tissue with a salt solution maintained at a pH between 7 and 10 and of sufficient concentration to produce an anion concentration of between about one mole per litre of mixture and about saturation, and recovering heparin from the mixture. The preferred salt employed is sodium chloride at a concentration of at least about 60 gms. per litre, preferably 100 to 150 gms. per litre. Other salts specified are the alkali metal and ammonium citrates, halides, acetates, sulphates or thiocyanates or alkaline earth halides, acetates or citrates. The extraction temperature may vary from 0 DEG -100 DEG C., preferably 20 DEG -60 DEG C. Heparin may be recovered from the salt extract, after filtration, by acidification to a pH of less than 4 to precipitate the protein, separating the protein by centrifugation or filtration, and recovering the partially purified heparin from the filtrate by addition of an alcohol, acetone, or other water miscible organic solvent. When the soluble salt used in the extraction is not very soluble in the water-miscible solvent, it is desirable to subject the filtrate to dialysis before precipitating heparin or to dissolve the precipitated heparin in water, dialyse the solution and then reprecipitate the heparin. Heparin can also be recovered by acidifying the salt extract to precipitate the protein, separating the protein by filtration, and adding a fatty amine such as octylamine or dodecylamine to the filtrate to precipitate an amine-heparin salt. The heparin is recovered from the amine-heparin salt by reslurrying the salt in water with an alkali at a pH of about 10 to dissociate the salt, filtering, and adding alcohol or acetone to the filtrate to precipitate the heparin. A further method of recovering heparin from the salt extract comprises removing the salt from the original extract by dialysis, acidifying the dialysate to a pH of less than 4 to precipitate the heparin-protein complex, redissolving the complex in water at a pH between about 7 and 10, adding sufficient water soluble salt to the mixture to produce an anion concentration of between about one mole per litre of mixture, and about saturation, acidifying the mixture to a pH of less than 4 to precipitate the protein and separating the protein and recovering heparin from the remaining solution by adding methyl or ethyl alcohol or other water miscible organic solvent. Specification 754,885 is referred to.