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The objective of the study was to analyze the effect of controlled and uncontrolled freezing step of a lyophilization process on the extent of non-enzymatic glycation and aggregation of an IgG1 formulation at two concentrations (1mg/ml and 20mg/ml). The degree of glycation (%) was determined through boronate affinity chromatography and its effect on the formation of soluble aggregates and higher molecular weight species was studied using dynamic light scattering (DLS) and size exclusion chromatography with multi-angle light scattering (SEC-MALS). The effect of non-enzymatic glycation on the secondary structure of the formulations was also studied using circular dichroism (CD) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. Results indicated that controlled nucleation yielded higher residual moisture contents and significantly lower specific surface areas for the two monoclonal antibody concentrations compared with uncontrolled nucleation cycle (p<0.05). For the two concentrations, uncontrolled nucleation resulted in significantly higher levels of glycation compared with controlled nucleation samples (p<0.05). Further, it was observed that higher storage temperatures (25°C/60% RH) versus 5°C resulted in higher glycation. Even though SEC-MALS analyses of the low concentrated formulations did not reveal the formation of higher molecular weight species, DLS analyses at two storage conditions revealed increases in the hydrodynamic radii and polydispersity index of the reconstituted formulations, suggesting the onset of formation of smaller species in the formulations. CD spectroscopy did not reveal any differences in the secondary structure of the mAb for the two concentrations after lyophilization. In conclusion, the freezing step method impacted the extent of glycation in lyophilized samples and the hydrolyzed component of sucrose was critical for increasing glycation. Even though some level of glycation was observed in lyophilized samples, the native structure of the protein was not affected. Further, it was demonstrated that storage of both lyophilized cakes and reconstituted formulations at higher temperatures could increase the extent of glycation in monoclonal antibody formulations., (Published by Elsevier B.V.)

An efficient and potentially scalable technology was evaluated to control the ice nucleation step of the freezing process for a model monoclonal antibody formulation and the effect on process performance and quality attributes of the final lyophilized product was compared with the conventional shelf ramping method of freezing. Controlled ice nucleation resulted in uniform nucleation at temperatures between -2.3 and -3.2 °C while uncontrolled nucleation resulted in random nucleation at temperatures between -10 and -16.4 °C. The sublimation rate (dm/dt) during primary drying was higher in the controlled nucleation cycle (0.13 g/h/vial) than in the uncontrolled nucleation cycle (0.11 g/h/vial). This was due to the formation of larger ice crystals, leading to lower product resistance (Rp) and 19% reduction in the primary drying for the controlled nucleation cycle. Controlled ice nucleation resulted in lyophilized cakes with more acceptable appearance, no visible collapse or shrinkage and decreased reconstitution times compared with uncontrolled nucleation. There were no observed differences in the particle size, concentration (A280 nm) and presence of aggregates (A410 nm) between the two nucleation cycles when the lyophilized cakes were reconstituted. These were confirmed by SEC and protein A-HPLC analyses which showed similar peak shapes and retention times between the two cycles. However, uncontrolled nucleation resulted in cakes with larger specific surface area (0.90 m(2)/g) than controlled nucleation (0.46 m(2)/g). SEM images of the lyophilized cakes from uncontrolled nucleation revealed a sponge-like morphology with smaller pores while cakes from controlled nucleation cycle revealed plate-like structures with more open and larger pores. While controlled nucleation resulted in a final product with a higher residual moisture content (2.1±0.08%) than uncontrolled nucleation (1.62±0.11%), this was resolved by increasing the secondary drying temperature., (Published by Elsevier B.V.)