Isoelectric Point Determination of Antibody Drugs

Antibody drugs are a class of drugs that treat diseases through artificially synthesized antibodies, which bind specifically to target molecules to achieve therapeutic purposes. Common types of antibody drugs include monoclonal antibodies, artificially synthesized antibody fragments, immunotoxins, and antibody-drug conjugates. Antibody drugs have shown significant efficacy in treating various diseases, such as cancer, autoimmune diseases, inflammatory diseases, immunomodulation, and ophthalmic diseases. The charge heterogeneity is a key attribute of antibody drugs, which has a significant impact on the stability, solubility, in vivo and in vitro biological activity, and kinetic function of the drug. The characterization of the charge heterogeneity of antibody drugs primarily involves the determination of the isoelectric point.

 

The isoelectric point refers to the pH value at which a molecule carries no net charge or is electrically neutral on average. Accurate determination of the isoelectric point is an effective means of identifying antibody drugs, as the isoelectric point of a specific protein is fixed, which is related to the composition and conformation of the protein. The methods used to determine the isoelectric point of antibody drugs mainly include precipitation method, spectrophotometry, and isoelectric focusing, etc. The isoelectric focusing method based on capillary electrophoresis has become a powerful tool for the determination of the isoelectric point due to its short time consumption, high accuracy, and small sample volume. Capillary isoelectric focusing utilizes the principle that the net charge of the protein is zero at the isoelectric point to carry out polyacrylamide gel electrophoresis of the protein to be tested in a special buffer solution. This special buffer solution is an amphoteric electrolyte, which can form a continuous pH gradient within the gel. At the end of electrophoresis, the position where the protein migrates corresponds to the pH of the isoelectric point of the protein.

 

MtoZ Biolabs provides customers with drug quality research services that comply with global drug regulatory regulations. We provide you with a comprehensive solution for antibody drug isoelectric point determination service package based on capillary isoelectric focusing (cIEF), including method development, validation, and subsequent sample testing.