Thermodynamic Stability of Recombinant Human Serum Albumin-Peg-water Systems

Abstract

There are much research addressing the behavior of mixtures of proteins and polymers. Until this moment, however, there are no papers that specifically address to the aqueous mixtures of recombinant human albumin. This work aims to evaluate the thermodynamic stability of the ternary mixture composed of water, polyethylene glycol and recombinant human albumin (rHSA) for use as a coating solution for disposable products from the extracorporeal membrane oxygenation (ECMO) systems. The experiments were carried out in an equilibrium cell and to quantify the rHSA concentration spectrophotometric assays were performed using the Brandford method. UNIQUAC thermodynamic model was used to calculate Gibbs energy of mixture as well as Gibbs distance function to identify whether the system is stable. The formation of a second phase was not observed, indicating that the mixture remains stable under the applied conditions, confirming what was seen in the experimental work. Diluted protein-PEG solutions do not form a two-phase system especially with low molecular weight PEG. However, it is important that future works can evaluate other experimental conditions to settle a range of stability, filling the lack of experimental data in literature.