RESUMO
The aim of this study was to establish and evaluate a screening method for the physical characterization of protein-protein interactions of therapeutic proteins based on the determination of the osmotic second virial coefficient (B(22)). B(22) of an IgG1 was measured by self-interaction chromatography (SIC) and was compared to data obtained from static light scattering (SLS). As assessed by Fourier transform infrared spectroscopy (FTIR), the protein coupling to chromatography particles had no relevant influence on the three-dimensional native structure of the IgG1. B(22) variations could be measured for physiological relevant excipient concentrations. Significant positive B(22) values were observed for the following solution conditions of the investigated antibody: (i) acidic pH conditions, (ii) low buffer concentrations, (iii) low salt concentrations and (iv) high amino acid concentrations. B(22) was compared to IgG1 stability data derived from a study conducted for 12weeks at 40 degrees C. A concentration of 5mM histidine, which was the most promising buffer candidate according to B(22), showed a slightly better physical stability (as assessed by turbidity and size exclusion chromatography) compared to the other tested formulations. This is confirmed in a stress study investigating the colloidal stability. Thus, measuring protein-protein interactions with SIC appeared as a promising screening tool for physical characterization of protein formulations for cases in which the protein stability is governed by interparticle interactions.