The effect of Tween® 20 on silicone oil-fusion protein interactions

There is evidence in the literature that silicone oil, a lubricant, can induce aggregation in protein formulations delivered through prefilled syringes. Surfactants are commonly used to minimize protein-silicone oil and protein-container interactions; however, these interactions are not well characterized and understood. The purpose of this manuscript was to understand the competitive interactions of a fusion protein with the silicone oil in the presence of Tween (R) 20. An adsorption isotherm for Tween (R) 20 at the silicone oil/water interface, using silicone oil coated quartz crystals, was generated at 25 degrees C to identify surface saturation concentrations. A concentration of Tween (R) 20 providing interfacial saturation was selected for protein adsorption studies at the silicone oil/water interface. The surfactant molecules adsorbed at the interface in a monolayer with a reduced viscoelastic character in comparison to the bound protein layer. A significant reduction in protein adsorption was observed when the surfactant was present at the interface. No desorption of the pre-adsorbed protein molecules was observed when Tween (R) 20 was introduced, suggesting that the protein has strong interactions with the interface. However, both, Tween (R) 20 and protein, adsorbed to the silicone oil/water interface when adsorption was carried out from a mixture of protein and Tween (R) 20. (c) 2012 Elsevier B.V. All rights reserved.