Process for the filtration of a suspension containing a protein such as an influenza virus vaccine

Claim 2

A PROCESS FOR THE FILTRATION OF A SUSPENSION CONTAINING AN INFLUENZA VIRUS, WHICH COMPRISES ADDING FROM 0.1 TO 4 PERCENT BY WEIGHT OF GELATINE TO THE SUSPENSION HAVING A PH OF ABOUT 7.8, AND FILTERING THE GELATINE CONTAINING SUSPENSION THROUGH A FILTERING PRESS CONTAINING A STACK OF MEMBRANES PRIMARILY COMPOSED OF CELLULOSE DERIVATIVES HAVING A PORE SIZE OF FROM 8.0UM TO 0.22UM ARRANGED IN ORDER OF DECREASING POROSITIES IN THE DIRECTION OF FLUID FLOW; SAID STACK OF MEMBRANES BEING CONVERED BY A PRE-FILTER, AND KEEPING A CONSTANT FLOW RATE OF THE GELATINE CONTAINING SUSPENSION WHICH BEING FILTERED BY APPLYING INCREASING AIR PRESSURE TO THE GELATINE CONTAINING SUSPENSION.

Claim 3

The process of claim 1 wherein said amounts of gelatine vary between, 0.1 and 2.0 percent by weight.

Claim 4

Process according to claim 1, wherein said gelatine is added in amounts of 0.2 percent by weight.

Claim 5

Process according to claim 1, wherein said suspension contains about 25 to 35 percent sucrose.

Claim 6

Process according to claim 1, wherein said air pressure is increased from 10 to 100 pounds per square inch.

Claim 7

Process according to claim 4, wherein sodium ethyl mercurithiosalicylate is added to said suspension prior to said filtering.

Claim 8

Process according to claim 1, wherein said sodium ethyl mercurithiosalicylate is added until a final concentration of 1/10,000 is reached.

Claim 9

Process according to claim 1, wherein said pre-filter is a glass-wool pre-filter.

Claim 10

Process according to claim 1, wherein the membranes have a diameter between about 140 and 300 mm.

Claim 11

Process accroding to claim 1, wherein the filtering press contains the following membranes disposed in order in the direction of fluid flow: 1- a glass wool pre-filter 2- a 8.0 Mu m membrane 3- a 3.0 Mu m membrane 4- a 1,2 Mu m membrane 5- a 0.8 Mu m membrane 6- a 0.45 Mu m membrane.

Claim 12

Process for the filtration of a suspension containing an influenza virus vaccine, about 30 percent sucrose and tris(hydroxymethyl) aminoethane-ethylene diamine tetraacetic acid buffer, which comprises adding about 0.2 percent by weight of gelatine to said suspension, having a pH of about 7.8 thereafter adding sodium ethyl mercurithiosalicylate to the gelatine containing suspension until a final concentration of 1/10,000 is obtained, filtering the suspension over a filtering press having a diameter between about 140 and 300mm containing the following membranes, primarily composed of cellulose derivatives arranged in order of decreasing porosities in the direction of fluid flow: 1- a glass wool pre-filter 2- a 8.0 Mu m membrane 3- a 3.0 Mu m membrane 4- a 1.2 Mu m membrane 5- a 0.8 Mu m membrane 6- a 0.45 Mu m membrane 7- a 0.22 Mu m membrane and keeping a constant flow rate of the gelatine containing suspension which is being filtered by applying increasing amounts of air pressure of from about 10 to about 100 pounds per square inch to said gelatine containing suspension.

Claim 13

Process for the filtration of a suspension containing an influenza virus vaccine, about 30 percent sucrose and tris(hydroxymethyl) aminoethane-ethylene diamine tetraacetic acid buffer, which comprises adding about 0.2 percent by weight of gelatine to said suspension, having a pH of about 7.8 thereafter adding sodium ethyl mercurithiosalicylate to the gelatine containing suspension until a final concentration of 1/10,000 is obtained, filtering the suspension over a filtering press having a diameter between about 140 and 300mm containing the following membranes, primarily composed of cellulose derivatives arranged in order of decreasing porosities in the direction of fluid flow: 1- a glass wool pre-filter 2- a 8.0 Mu m membrane 3- a 3.0 Mu m membrane 4- a 1.2 Mu m membrane 5- a 0.8 Mu m membrane 6- a 0.45 Mu m membrane 7- a 0.22 Mu m membrane and keeping a constant flow rate of the gelatine containing suspension which is being filtered by applying increasing amounts of air pressure of from about 10 to about 100 pounds per square inch to said gelatine containing suspension.