Effect of membrane pore structure on fouling behavior of glycoconjugate vaccines

Sterile filtration can be difficult when processing large glycoconjugate vaccines. The objective of this work was to evaluate the performance of three commercial 0.2 μm nominal pore size sterilizing grade membranes with very different morphology: Millipore Durapore® (homogeneous), Millipore Express® (asymmetric), and Sartopore® Platinum (dual layer) during sterile filtration of a glycoconjugate vaccine provided by Pfizer. The location of deposited glycoconjugate within the filters was examined by confocal microscopy. The greatest capacity was obtained with the asymmetric membrane due to its high permeability, while the lowest capacity was found with the two-layer membrane in which the fouling occurred at the entrance to the 0.2 μm layer. The pressure profiles during constant flux filtration were analyzed using a modified intermediate pore blockage model accounting for the fouled and unfouled regions within the filter, providing additional insights into the effects of membrane morphology on the fouling characteristics.