title: The Effect of Shear on the Structural Conformation of rhGH and IgG1 in Free Solution.
abstract: The effect of hydrodynamic forces on proteins in free solution, also referred to as shear stress in multiple drug substance and drug product processing steps, was investigated by means of in situ and inline biophysical measurements. The use of a quartz Couette cell in combination with a circular dichroism spectrometer allowed simultaneously the creation of simple shear flow and direct measurements of the proteins' secondary and tertiary structure. Recombinant human growth hormone and an IgG1 mAb were chosen as model proteins. Under the exclusion of interfacial effects by the addition of a surfactant, no unfolding was observed due to shearing for 30 min up to the highest possible shear rate under laminar flow (3840 s(-1)). In another experiment, guanidine hydrochloride was added to a surfactant-protected and sheared sample to lower the thermodynamic and mechanical stability of the proteins. However, even under these destabilizing conditions, the proteins showed no change in their secondary and tertiary structure. We conclude that shear stress in terms of velocity gradients is unlikely to unfold the investigated proteins in free solution up to shear rates of at least 10(4) s(-1).
authors.affiliation: Department of Pharmaceutical Development, Sandoz GmbH, 6336 Langkampfen, Austria; Department of Biotechnology, University of Natural Resources and Applied Life Sciences Vienna, 1190 Vienna, Austria. Electronic address: lukas.brueckl@sandoz.com.
authors.forename: Lukas
authors.initials: L
authors.lastname: Brückl
authors.affiliation: Department of Pharmaceutical Development, Sandoz GmbH, 6336 Langkampfen, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schröder
authors.affiliation: Department of Pharmaceutical Development, Sandoz GmbH, 6336 Langkampfen, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Scheler
authors.affiliation: Department of Biotechnology, University of Natural Resources and Applied Life Sciences Vienna, 1190 Vienna, Austria.
authors.forename: Rainer
authors.initials: R
authors.lastname: Hahn
authors.affiliation: Department of Pharmaceutical Development, Sandoz GmbH, 6336 Langkampfen, Austria.
authors.forename: Corinna
authors.initials: C
authors.lastname: Sonderegger
mesh_terms: D019382:Human Growth Hormone / Q000737:chemistry*; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry*; D019999:Pharmaceutical Solutions / Q000737:chemistry; D066329:Protein Aggregates; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry; D033081:Shear Strength
chemical_list: D007074:Immunoglobulin G; D019999:Pharmaceutical Solutions; D066329:Protein Aggregates; D011994:Recombinant Proteins; D019382:Human Growth Hormone
keywords: IgG antibody; circular dichroism; physical stability; protein aggregation; surfactants