Antibody Drug Conjugates (ADCs) are biopharmaceutical drugs which are designed to treat cancer by targeting and killing the cancerous cells while leaving the healthy tissue intact. ADCs are comprised of an antibody connected to a cytotoxic drug by a linker.

The antibody targets a specific antigen which is present in cancerous cells but not healthy cells. The ADC binds to the cancer cell and becomes internalized where the cytotoxic drug is released and kills the cancer cell.

Two important pieces of information required about the ADC are the protein concentration and the Drug-Antibody Ratio (DAR). The DAR is the number of drug molecules attached to the antibody. It is important during the manufacturing steps to ensure that the process is proceeding as expected and that there is not more or less drug present than required.
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Corresponding Authors: Melissa Nixon and Bérengère François
Key terms: ADC, bioconjugation, Mass Spectroscopy, hydrophobic interaction chromatography, Drug-Antibody Ratio, reverse phase chromatography
Published In: ADC Review| Journal of Antibody-drug Conjugates
Acknowledgments:
Conor Barry, Head of Development, Piramal Pharma Solutions
Joe Ferraiolo, Director, Bioanalytics Applications, Repligen Corporation
DOI: 10.14229/jadc.2023.12.05.001.
How to cite:
Nixon M. 1 and François B. 2 Validation of ADC Platform for Protein Concentration and the Drug-Antibody Ratio (DAR) using Variable Pathlength Technology – J. ADC. December 5, 2023. DOI: 10.14229/jadc.2023.12.05.001.
1 Analytical Development Scientist at Piramal Pharma Solutions;
2 Sr. Bioanalytics Applications Specialist at Repligen Corporation
Last Editorial Review: December 4, 2023
Article History:
- Original Manuscript Received November 10, 2023
- Review results received December 1, 2023
- Manuscript accepted for publication December 4, 2023
Featured image: Antibody. Photo courtesy: © 2016 – 2023 – Fotolia/Adobe. Used with permission.











