This study provides the first systematic investigation of the impact of the nucleation protocol during freeze-drying on physico-chemical properties and long-term stability of two IgG1 antibodies in sugar formulations. We hypothesized that the lower specific surface area (SSA) generated by controlled nucleation could be beneficial for the stability of interface sensitive proteins. The study compares controlled nucleated (CN) and randomly nucleated (RN) lyophilizates with high and low antibody concentrations stored at different temperatures. Formulations with and without polysorbate (PS) were included.
In the “high concentration” study the formulation without PS showed reduced particle formation for CN samples compared to RN samples. PS containing formulations had an overall lower particle level with no further advantage of CN on stability. Besides the intended comparison of CN and RN samples, we observed that PS promoted sucrose crystallization in both low concentration antibody studies during storage. Additionally, our results indicate that the nucleation temperature (TN) was not the only determining factor for the resulting ice crystal size and consequently the product`s SSA.
Overall, the application of CN had neither a positive nor a negative impact on the product's physico-chemical stability. The surfactant had a much higher stabilizing effect than the reduction of the SSA by CN.