Blood compatible polymers for blood oxygenation devices
AssigneeNorth Star Research Institute
InventorRobert J. Petersen
Life of this patent
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Abstract
Fluoroacylation of ethyl cellulose has been found to result in good gas permeability and blood compatibility for polymeric layers made from the resulting fluorinated esters. The fluoroacylated ethyl cellulose has good hydrolytic stability at blood pH and under sterilization conditions (e.g. 100.degree. C). For use in blood oxygenation devices, implantable biomedical devices, blood sampling or analysis or purification devices, etc., it is preferred that the fluoroacylated ethyl cellulose be substantially free of residual OH and have a fluorine content above 10% by weight (e.g. at least about 12% by weight).
Claims5
In a blood oxygenation device comprising a means for bringing blood into contact with a gas-permeable support means and a means for conveying oxygenating gas to the other side of the gas-permeable support means, the improvement which comprises:
- a coating comprising fluoroacylated ethyl cellulose as a gas-permeable coating on said gas-permeable support means and for being in contact with the blood;
- wherein said fluorinated ethyl cellulose has a calculated chemically combined fluorine content of at least about 10% by weight and a degree of substitution ranging from about 1.0 to about 2.75, and wherein substantially all residual hydroxyls, including ring-substituted hydroxyls, have been converted to fluorinated ester groups of the formula --OCO(CF.sub.2).sub.m CF.sub.3, wherein m is a number ranging from 1 to 6;
- said fluoroacylated ethyl cellulose containing, at most, trace amounts of residual hydroxyl groups as determined by infrared analysis.
A blood oxygenation device comprising:
- means for bringing blood of a living animal into contact with a major surface of a gas permeable membrane, and
- means for bringing oxygen gas into contact with the opposite major surface of said gas permeable membrane, said gas permeable membrane comprising an ethyl cellulose derivative which has a degree of substitution ranging from about 1.0 to about 2.75 and wherein substantially all residual hydroxyls, including substantially all ring-substituted hydroxyls, have been converted to fluorinated ester groups of the formula --OCO(CF.sub.2).sub.m CF.sub.3, wherein m is a number ranging from 1 to 6, said ethyl cellulose derivative containing, at most, trace amounts of residual hydroxyl groups as determined by infrared spectroscopic analysis;
- said ethyl cellulose derivative having a calculated chemically combined fluorine content of at least about 10% by weight.
Dependencies are inferred from the claim text.