Choose an application

• Reference Manager
• EndNote
• RefWorks (Direct export to RefWorks)

Monoclonal antibodies are becoming increasingly important in the pharmaceutical industry. The fact that they are required in such high concentrations in liquid formulations creates an even higher risk of aggregation of the antibodies. Aggregation substantially increases the risk of unwanted immunogenicity. Therefore, further research into the aggregation mechanisms is recommended. The aim of this master thesis is to better understand the influence of different excipients on the stability of an IgG4 monoclonal antibody. The chosen excipients were polyols (glycerol, erythritol, xylitol, sorbitol, maltitol, PEG300) and amino acids (L-arginine hydrochloride, L-lysine hydrochloride, L-glycine, L-proline, L-valine). These excipients were investigated in two buffers with different pH value. Mechanisms regarding the monoclonal antibody stability as well as the aggregation mechanisms are analyzed. The data obtained from the stability study at different temperatures (5, 30, 40 and 50 ° C) using size-exclusion chromatography (SEC) with in-line multi-angle light scattering (MALS) detection as well as dynamic light scattering (DLS) is used to to unravel and better understand the aggregation mechanisms. This data will be related to biophysical parameters including denaturation midpoint temperature (Tm) and aggregation temperature (Tagg), determined by differential scanning fluorimetry (DSF) and preferential interaction coefficient, measured by vapor pressure osmometry (VPO). A clear difference is seen between the effect of polyols and amino acids on stability, but also a difference in behavior of the excipients in the buffers with different pH value. The polyol formulations show a reduction in aggregation rates as their size increases. From a certain polyol size, sorbitol in this study, the aggregation rate remains more constant. No big differences in aggregation rate are seen between sorbitol and maltitol. The addition of basic amino acids causes a faster aggregation at higher temperatures. Compared to the aggregation rates of formulations containing L-arginine hydrochloride the formulations containing neutral amino acids with guanidine hydrochloride show a higher aggregation rate. Positive preferential interaction coefficients are determined between the protein and L-arginine hydrochloride, pH 4.6 and guanidine hydrochloride, pH 7.6 indicating preferential interaction between these excipients and the monoclonal antibody. Sorbitol, like the neutral amino acids L-glycine and L-proline, shows negative interaction coefficients at both pH’s. These negative coefficients show that the excipients are excluded from the protein surface. This indicates stabilization of the protein contrary to preferential interaction, which leads to destabilization.