Quality by design (QbD) approach to SE-HPLC method development for cetuximab Monoclonal antibodies

A novel, stability-indicating SE-HPLC method was developed and validated for the quantitative assessment of high molecular weight species (HMWP) and monomers in Cetuximab, a therapeutic monoclonal antibody used in the treatment of metastatic colorectal cancer and squamous cell carcinoma of the head and neck. This method accounts for degradation products generated during forced degradation studies, in accordance with ICH guidelines. The HPLC system was employed with a TSKgel G3000SWXL column at 48 °C with detection at 220 nm. The mobile phase consisted of 25 mM sodium phosphate buffer (pH 8.0) containing 250 mM NaCl with a flow rate of 0.85 mL/min. The method demonstrated excellent environmental sustainability as it is entirely aqueous-based, requiring no organic solvents. The calibration curve demonstrated excellent linearity between 0.5 and 1.5 mg/mL, with an R² value exceeding 0.999. The method's limits of detection and quantitation were determined and found to be satisfactory, with robust accuracy and precision. Under thermal stress conditions (50 °C for 1 hour), the presence of degradation products did not interfere with the detection of HMWP and monomers, confirming the method's stability-indicating capability. The forced degradation study revealed an increase in HMWP content, demonstrating the method's ability to effectively separate and quantify degradation products. This developed SE-HPLC method offers advantages over previously published methods through its systematic Quality by design (QbD)-based development, comprehensive design space definition, and enhanced robustness demonstrated through the Method Operable Design Region (MODR), making it suitable for quality control quantification of HMWP and monomers in Cetuximab, as well as for stability studies.