High-resolution virus removal methodology and filtration capsule useful therefor

Abstract

The present invention provides a high-resolution membrane-based method for removing a virus from a manufactured protein-containing solution, the method being particularly characterized by its capacity to be performed quickly (i.e., as measured by flux) and efficiently (i.e., as measured by log reduction value, LRV). Towards such results, the present invention employs a plurality (i.e., greater than 2) of interfacially-contiguous asymmetric ultrafiltration membranes, the foremost of which is oriented with its “tight side” facing downstream. The present invention also provides a filtration capsule, useful in the conduct of the method, comprising a pleated tube formed of three interfacially-contiguous asymmetric ultrafiltration membranes.

1 . A filtration capsule, suitable for use in virus removal methodologies, comprising a tubular housing though which a fluid process stream can be conducted, the housing having a fluid inlet and a filtrate outlet, and containing a pleated tube composed of three interfacially-abutting asymmetric membranes, wherein the pleated tube is positioned within said process stream between said fluid inlet and said filtrate outlet, and wherein each asymmetric membranes is: 
 (a) substantially hydrophilic,    (b) capable of substantially preventing the passage therethrough of viruses,    (c) provided with a tight-side and an open-side, the average pore size of said tight-side being less than the average pore size of said open-side, and    (d) oriented such that fluid introduced into said housing through the fluid inlet commences passage through each asymmetric membrane through its open-side.    
   
   
       2 . The filtration capsule of  claim 1 , wherein the asymmetric membranes are each capable of substantially permitting the passage therethrough of protein.  
   
   
       3 . The filtration capsule of  claim 1 , wherein each asymmetric membrane is composed of cellulosic material.  
   
   
       4 . The filtration capsule of  claim 1 , wherein each asymmetric membrane is composed of polyethersulfone.  
   
   
       5 . A filtration capsule comprising a housing through which a fluid process stream can be conducted, the housing having a fluid inlet and a filtrate outlet, and containing a plurality of interfacially-abutting asymmetric membranes; 
 said asymmetric membranes being positioned within said process stream between said fluid inlet and said filtrate outlet, each asymmetric membrane being (a) substantially hydrophilic, (b) capable of substantially preventing the passage there-through of a virus, 9c) provided with a tight-side and an open-side, the average pore size of said tight-side being less than the average pore size of said op[en-side, and (d) oriented such that fluid introduced into said housing through the fluid inlet commences passage through each asymmetric membrane though its open-side; and    said filtration capsule capable of selectively removing said virus from a manufactured protein-containing solution, in a normal flow filtration mode, at a log reduction value (LRV) greater than 6 and a protein passage greater than 98%, the predominant solute in said solution being said protein.