Importance

Loading Importance Indicators...

Abstract

A method for preventing activation of the contact phase of blood or plasma which comes into contact with a semi-permeable membrane based on polyacrylonitrile bearing fixed negative charges, which is fitted in apparatus for the treatment of blood or plasma, by extra-corporal circulation, said method comprising contacting blood or plasma with said semi-permeable membrane, wherein: a neutral or cationic polymer is combined with said semi-permeable membrane before or after formation of the membrane, and before sterilization of the membrane; the overall ionic capacity of the semi-permeable membrane, based on polyacrylonitrile bearing fixed negative charges and containing a neutral or cationic polymer, is negative; the overall ionic capacity of the semi-permeable membrane, based on polyacrylonitrile bearing fixed negative charges and containing a neutral or cationic polymer, is, as an absolute value, not more than 10% less than the overall ionic capacity of the same semi-permeable membrane without a neutral or cationic polymer, at least one of said polymer being present at the surface of the membrane; the semi-permeable membrane based on polyacrylonitrile bearing fixed negative charges and containing a neutral or cationic polymer complies, before sterilization, with the following two electrical characteristic: the electrokinetic index 'I' is less than or equal to 0.8, 'I' being equal to the logarithm, in base 10, of the ratio .vertline.Z.vertline./R, where 'Z' is the Zeta potential, as an absolute value, expressed in microvolts, of the surface of the membrane intended to come into contact with blood or plasma, and where 'R' is the electrical resistivity of the membrane, expressed in ohm.centimeters, and the Zeta potential 'Z' is negative.

Loading the Abstract Image...

First Claim