Patent ID: 9272245
Filing Date: 2016-03-01
CPC Classification: A61L,A61P,B01D,C07K

Claim Text:
1. A filtration method for filtering an intermediate protein product having a predetermined protein concentration through a virus removal filter at a predetermined pressure, comprising: (1) using a virus removal filter that comprises a container that has at least one inlet and at least one outlet, and a virus removal membrane that is made of a hydrophilized synthetic polymer for removing viruses from the intermediate protein product, the space inside the container is divided by the virus removal membrane into an inlet-side space and an outlet-side space, at least the inlet of the container has a nozzle having a fitting structure that has a pressure resistance of 600 kPa or more, and the virus removal membrane has an effective membrane area of 0.0001 to 0.03 m (2) subjecting the intermediate protein product, which has a protein concentration of 30 to 100 mg/mL and has been pre-filtered, to dead-end filtration for 4 to 5 hours through the virus removal filter at an inlet pressure of 294 to 600 kPa and an average protein filtration rate of 1.6 kg/m (3) obtaining a filtrate of the intermediate protein product having a virus removal rate (LRV: logarithmic reduction value) of 3 or more.