Degradation and in-use stability study of five marketed therapeutic monoclonal antibodies by generic weak cation exchange liquid chromatographic method ((WCX)HPLC/DAD).

Therapeutic monoclonal antibodies (mAbs) represent a very important class of the current biopharmaceutics. The great complexity of their structure made necessary the use of different analytical approaches for assessing different physico-chemical properties. In this work, weak cation exchange (WCX) high performance liquid chromatography with diode array detection ((WCX)HPLC/DAD) is used to assess the charge variant profile. The method here developed combined the effect of ionic strength and controlled pH gradient and allows for the charge variants analysis of the five mAbs studied, namely bevacizumab (BVZ), cetuximab (CTX) infliximab (INF), rituximab (RTX) and trastuzumab (TTZ), which are among the most used mAbs worldwide. The differences in the charge variants in the natural isoforms of the mAbs promoted characteristic WCX chromatograms for each of mAbs that can be also useful for identification purposes. These chromatograms have provided to be suitable for tracking changes in the charge variants of each mAb analyzed both in controlled degraded and in stabilities study along time of in-use samples solutions at 2 mg/mL in 0.9% NaCl stored refrigerated (at 4 °C) and frozen (-20 °C) for two months. The results obtained indicated different stabilities of these mAbs, all IgG1, against degradation by different stressed environmental conditions and in-use stability along two months.