1Department of Medicinal Chemistry and Quality Control, University of Tishreen, Lattaquia, Syria
2University of Al Mashreq, College of Engineering Technology, Baghdad, Iraq
3MSC Pharmaceutical Chemistry, College of Pharmacy, University of Mustaqbal, Babylon, Iraq
4Department of Food and Anlytical Chemistry, University of Tishreen, Lattaquia, Syria
5Department of Medicinal Chemistry and Quality Control, University of AL-Rachid, Damascus, Syria
*Corresponding Author E-mail: profthallaj@gmail.com
Online published on 14 May, 2025.
This research aimed to analyze the charge variant profiles of monoclonal antibodies (mAbs) conjugated to maytansine derivatives or tomaymycin compounds via a non-cleavable linker, utilizing the imaging capillary isoelectric focusing (icIEF) technique. Initially, the charge variant profiles for three mAbs were assessed, revealing both major and minor variants among the samples. Specifically, mAB1 and mAB2 displayed two distinct charge variants with isoelectric points (pI) of 9.00 and 8.95, respectively. In contrast, mAB3 showed a predominant charge variant with a pI of 8.50, along with two minor variants (pI values of 8.30 and 8.60). The conjugation of mAB1 involved a maytansine derivative using non-cleavable linkers, while mAB2 and mAB3 were linked to tomaymycin molecules. The resulting non-cleavable antibody conjugates exhibited greater heterogeneity and acidity than their unconjugated forms. The observed pI ranges were 7.4 to 8.9 for mAB1 conjugates (ΔpI: 1.4), 8.2 to 8.9 for mAB2 (ΔpI: 0.7), and 7.4 to 8.4 for mAB3 (ΔpI: 1). The icIEF method proved effective for tracking the charge profiles of antibody-drug conjugates (ADCs), showing excellent repeatability for both intra-day and inter-day measurements for unconjugated mAbs and ADCs.
Monoclonal Antibodies, Conjugates, Icief, Charge Variant Profile
