Relevant shaking stress conditions for antibody preformulation development

In protein formulation development, shaking stress is often employed to assess the physical stability of antibody formulations against aggregation. Since there are currently no guidelines describing suitable test conditions, very different shaking stress designs are used. These different designs may influence the resulting stability data. The aim of this study was to establish a shaking stress design within the protein range of 2–5 mg/ml which can rapidly distinguish between antibody formulations of poor stability and those with potential for further development. Small scale shaking stress experiments were performed with different monoclonal IgG antibodies (as buffered solutions or marketed formulations). Variables were the filling degree of the sample containers, the container type and size and the shaking intensity. The stability of the samples was assessed by visual inspection, UV–VIS spectrophotometric turbidity measurements and size exclusion chromatography. All tested parameters had a strong influence on the stability results. The most discriminating conditions were obtained when shaking of the formulations was performed at 200 rpm in a 2 ml injection vial filled with 1 ml protein solution. This experimental setup led to clearly different stability results for buffered solutions and marketed products. Moreover, this setup required only relatively small amounts of protein solution which is advantageous in prefomulation studies.