The effect of formulation excipients on protein stability and aerosol performance of spray-dried powders of a recombinant humanized anti-IgE monoclonal antibody

Purpose. To study the effect of trehalose, lactose, and mannitol on the bio chemical stability and aerosol performance of spray-dried powders of an ant i-IgE humanized monoclonal antibody. Methods. Protein aggregation of spray-dried powders stored at various tempe rature and relative humidity conditions was assayed by size exclusion chrom atography and sodium dodecyl sulfate polyacrylamide gel electrophoresis. Pr otein glycation was determined by isoelectric focusing and affinity chromat ography. Crystallization was examined by X-ray powder diffraction. Aerosol performance was assessed as the fine particle fraction (FPF) of the powders blended with coarse carrier lactose, and was determined using a multiple s tage liquid impinger. Results. Soluble protein aggregation consisting of non-covalent and disulfi de-linked covalent dimers and trimers occurred during storage. Aggregate wa s minimized by formulation with trehalose at or above a molar ratio in the range of 300:1 to 500:1 (excipient:protein). However, the powders were exce ssively cohesive and unsuitable for aerosol administration. Lactose had a s imilar stabilizing effect, and the powders exhibited acceptable aerosol per formance, but protein glycation was observed during storage. The addition o f mannitol also reduced aggregation, while maintaining the FPF but only up to a molar ratio of 200:1. Further increased mannitol resulted in crystalli zation, which had a detrimental effect on protein stability and aerosol per formance. Conclusions. Protein stability was improved by formulation with carbohydrat e. However, a balance must be achieved between the addition of enough stabi lizer to improve protein biochemical stability without compromising blended powder aerosol performance.