PT  - JOURNAL ARTICLE
AU  - Cao, Mingyan
AU  - Mo, Wenjun (David)
AU  - Shannon, Anthony
AU  - Wei, Ziping
AU  - Washabaugh, Michael
AU  - Cash, Patricia
TI  - Qualification of a Quantitative Method for Monitoring Aspartate Isomerization of a Monoclonal Antibody by Focused Peptide Mapping
AID  - 10.5731/pdajpst.2015.006239
DP  - 2016 Jan 01
TA  - PDA Journal of Pharmaceutical Science and Technology
PG  - pdajpst.2015.006239
4099  - http://journal.pda.org/content/early/2016/04/13/pdajpst.2015.006239.short
4100  - http://journal.pda.org/content/early/2016/04/13/pdajpst.2015.006239.full
AB  - Aspartate (Asp) isomerization is a common post-translational modification of recombinant therapeutic proteins that can occur during manufacturing, storage, or administration. Asp-isomerization in the complementarity-determining regions (CDRs) of a monoclonal antibody (mAb) may impact the target binding and thus a QC friendly method for routine monitoring is desirable. In this work, we utilized a liquid chromatography mass spectrometry (LC/MS)-based approach to identify the Asp isomerization in the CDRs of a therapeutic mAb. To quantitate the site-specific Asp-isomerization of the mAb, a UV detection-based quantitation assay utilizing the same LC platform was developed. The assay was qualified, and implemented for routine monitoring of this product-specific modification. Compared with existing methods, this analytical paradigm is applicable to identify Asp-isomerization (or other modifications), and subsequently develop a rapid, QC friendly test for routine site specific monitoring and quantitation to ensure product quality. This approach first identifies and locates a product- related impurity (a CQA) caused by isomerization, deamidation, oxidation or other post-translational modifications, and then utilizes synthetic peptides and mass spectrometry to assist the development of a LC-UV based chromatographic method which separates and quantifies the product related-impurities by UV peaks. The established LC-UV method has acceptable peak specificity, precision, linearity and accuracy; it can be validated and used in GMP environment for lot release and stability testing.