HOLLOW-FIBER BLOOD-PURIFYING MEMBRANE AND PROCESS FOR PRODUCING THE SAME

A hollow-fiber blood-purifying membrane comprising substantially cellulose acetate, wherein cellulose acetate polymer particles distribute substantially nondirectionally on the inner surface of the hollow fiber and the inner and outer surfaces of the fiber have each a densified layer with a thickness of 30-1,000 nm, the membrane wall part between two such layers having a substantially homogeneous porous structure, and which has an in vitro ultrafiltration rate (UFR) of 10-50 ml/m .mmHg.hr, an in vivo UFR to in vitro UFR ratio of 0.3 or above, a plasma albumin permeation inhibition ratio of 90 % or above, and an in vivo beta 2-microglobulin ( beta 2-MG) sieving factor of 0.4 or above.