Characterization of Protein–Excipient Microheterogeneity in Biopharmaceutical Solid-State Formulations by Confocal Fluorescence Microscopy

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• 作者：Stijn H. S. Koshari ; Jean L. Ross ; Purnendu K. Nayak ; Isidro E. Zarraga ; Karthikan Rajagopal ; Norman J. Wagner ; Abraham M. Lenhoff
• 刊名：Molecular Pharmaceutics
• 出版年：2017
• 出版时间：February 6, 2017
• 年：2017
• 卷：14
• 期：2
• 页码：546-553
• 全文大小：505K
• ISSN：1543-8392

文摘

Protein-stabilizer microheterogeneity is believed to influence long-term protein stability in solid-state biopharmaceutical formulations and its characterization is therefore essential for the rational design of stable formulations. However, the spatial distribution of the protein and the stabilizer in a solid-state formulation is, in general, difficult to characterize because of the lack of a functional, simple, and reliable characterization technique. We demonstrate the use of confocal fluorescence microscopy with fluorescently labeled monoclonal antibodies (mAbs) and antibody fragments (Fabs) to directly visualize three-dimensional particle morphologies and protein distributions in dried biopharmaceutical formulations, without restrictions on processing conditions or the need for extensive data analysis. While industrially relevant lyophilization procedures of a model IgG1 mAb generally lead to uniform protein–excipient distribution, the method shows that specific spray-drying conditions lead to distinct protein–excipient segregation. Therefore, this method can enable more definitive optimization of formulation conditions than has previously been possible.