Boehringer Ingelheim Pharma GmbH & Co. KG, Formulation and Process Development Biologicals Late Stage, 88397 Biberach, Germany; Institute of Applied Biotechnology, Faculty for Biotechnology, Biberach University of Applied Sciences, 88400 Biberach, Germany; Faculty for Natural Sciences, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.