Optimizing An Automated CE-SDS Method For USP 129 Suitability

Since the first therapeutic monoclonal antibody (mAb) was commercialized in the mid-80’s, close to 100 therapeutic mAb products (accounting for around a quarter of all biotech drugs) have hit the market; making it a $125 billion industry that targets critical pathological health conditions – including but not limited to products for antitumor, antiviral, and antiplatelet therapies. From early-stage process development to batch lot release testing, the efficacy, safety, identity, stability, and purity of therapeutic mAb products throughout their shelf life are of crucial importance. Capillary electrophoresis sodium dodecyl sulfate (CE-SDS) has become the gold standard technique for the quality-control of therapeutic mAbs and proteins due to its ease of implementation, robustness, and reproducibility, replacing the more traditional and labor-intensive technique such as SDS-PAGE gel. Successful CE-SDS method development, under both reducing and nonreducing conditions, aims to reduce assay-associated impurities, fragmentations, and aggregations.

Here, we have used the monoclonal IgG System Suitability Reference Standard developed by U.S. Pharmacopeia (USP) to assess the rigor and robustness of an optimized Maurice™ CE-SDS PLUS method compared to the recommended USP protocol provided in monograph <129&GT. The optimization leveraged Design of Experiments (DOE) to optimize key components in sample preparation, denaturing conditions, and sample injection. The results show that the optimized methods: (1) cause less fragmentation compared to the USP <129&GT method, (2) are not susceptible to sample injection variations that might differ between instruments, and (3) provide comparable data to the USP <129&GT monograph for mAbs.