SEPARATION OF MONOCLONAL IGM ANTIBODIES USING TANGENTIAL FLOW ULTRAFILTRATION

Experimental results are presented for the separation of monoclonal Ig M antibodies from hybridoma cell cultures using tangential flow ultraf iltration with total recycle of the retentate. IgM antibodies are pent americ immunoglobulin molecules with a molar mass of 900 kDa and a tip -to-tip distance of 38 nm. The major impurity (foulant) in the superna tant sample was albumin, whose molar mass and diameter are 67 kDa and 7 nm, respectively. The antibody (product) recovery rate, variations i n the permeation velocity and the time for a 90%-reduction in feed vol ume were investigated using 100 and 300 kDa NMWCO membranes at three t ransmembrane pressures and two tangential velocities. A model is also presented, in which the ultrafiltration process is divided into two re gimes: the surface fouling regime (characterized by the adsorption of antibody molecules on the membrane surface) and the internal fouling r egime (characterized by pore-blockage due to deposition of foulant pro tein molecules). Approximately 16% of the effective membrane area was blocked in the surface fouling regime. The model predictions are in sa tisfactory agreement with the experimental results.