Thesis (Ph.D.) - Cairo University - Faculty of Pharmacy - Department of Analytical Chemistry

Forced degradation studies are crucial for the evaluation of the stability and biosimilarity. Here, anti-TNF (Tumor necrosis factor) products; infliximab and adalimumab were subjected to various stress conditions (oxidation, pH, temperature, agitation and repeated freeze{u2013}thaw cycles) in order to generate all possible degradation products. An orthogonal stability- indicating testing protocol comprising SE{u2010}HPLC, RP{u2010}HPLC, Tapestation gel electrophoresis, dynamic light scattering (DLS), and functional receptor binding assay was developed and validated. The assay protocol was used to evaluate the stability of anti-TNF products and to assess the biosimilarity of infliximab samples. Stability results cleared that both antibodies are susceptible to degradation induced by the studied stress conditions. The high molecular weight aggregates/low molecular weight fragments in addition to oxidized forms of infliximab and adalimumab were detected in all samples subjected to stress conditions to different degrees. Tapestation electrophoresis and dynamic light scattering (DLS) results were generally in agreement to those obtained using SE-HPLC assay. The formation of aggregates of both antibodies was found to occur via non-reducible covalent bonds

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