METHOD OF PREPARING LOW-MOLECULAR CHITOSAN FOR ANTIRADIATION PREPARATIONS Russian patent published in 2002 - IPC

FIELD: medicinal biotechnology. SUBSTANCE: enzymatic cleavage of a chitosan solution is carried out with a soluble complex of bacterial chinolytic enzymes at pH = 4.5-5.5, temperature 40-50 C for 30-60 min in the ratio chitinase activity/chitosan from 0.5 to 2.0 U activity/g of chitosan. Then the reaction mass is kept in boiling water bath for 3-7 min, cooled, concentrated, filtered and fractionated isolating the fraction with a value of mean viscous molecular mass from 8 to 12 kDa. The obtained solution is dialyzed against water and product is dried. The prepared substance is a water-soluble matter (up to 50 mg in 1 ml), easily sterilized by boiling and nontoxic. Viability of animals protected with the prepared chitosan is 75-90% as compared with their practically total death in control after irradiation by the dose 8.0 Gr. Invention can be used for the development the novel radioprotecting agents based on the natural polysaccharides. EFFECT: improved method of preparing, enhanced radioprotective effect. 1 tbl