Method for purifying mixtures of immunoglobulin & albumin

A method for the concurrent purification and isolation of albumin and IgG from a fluid composition containing up to about 15%, by weight, of blood plasma proteins obtained from a plasma source that has not previously undergone any prior fractionation. In this method, the composition is buffered and thereafter modified by the addition, relative to IgG, of a thermal stabilization effective amount of a polyhydric alcohol, and, by addition, relative to albumin, of a thermal stabilization effective amount of a carboxylic acid (e.g. carboxylic acid having about 3 to about 10 carbon atoms), or the physiologically acceptable salt of said. The resulting fluid composition is thereafter heated to and maintained at a temperature in the range sufficient to effect essentially complete denaturation of proteins, other than the albumin and the IgG components, of said composition. Thereafter, the fluid composition is cooled and the soluble components thereof, the albumin and IgG, isolated from the solids and suspended matter by a combination of filters designed to initially remove the solids and suspended matter from the fluid composition, and thereafter through an array of tangential flow filtration membranes capable of isolation of soluble protein components of said composition by molecular weight.