Patent ID: 8758625

Claim:
A method of use of a porous hollow fiber membrane for producing a clarified biomedical culture medium by a method including a filtration step of distributing a biomedical culture medium over the porous hollow fiber membrane, a tube wall of the hollow fiber membrane being constituted of a blend of a hydrophobic polymer and polyvinylpyrrolidone, wherein a content of the polyvinylpyrrolidone is not lower than 0.2% by mass and not higher than 3% by mass relative to a total mass of the porous hollow fiber membrane, and, when the tube wall is divided in a membrane-thickness direction equally into three regions, a content of the polyvinylpyrrolidone in an outer circumferential region including an outer face is higher than a content of the polyvinylpyrrolidone in an inner circumferential region including an inner face, and an average pore size in the inner face is larger than an average pore size in the outer face, wherein the porous hollow fiber membrane has an inner diameter of not smaller than 1000 μm and not larger than 2000 μm, and wherein the porous hollow fiber membrane satisfies the following formula (I): C out /C in ≧2 (I) wherein C out represents the content of the polyvinylpyrrolidone in the outer circumferential region, and C in represents the content of the polyvinylpyrrolidone in the inner circumferential region.