Simultaneous Enantiomeric Separation and Binding Constants Determination by Affinity Capillary Electrophoresis using Human Serum Albumin

Ratih, Ratih and Stein, Matthias and Asmari, Mufarreh and Deeb, Sami El (2019) Simultaneous Enantiomeric Separation and Binding Constants Determination by Affinity Capillary Electrophoresis using Human Serum Albumin. In: 48th International symposium on high-performance liquid phase separations and related techniques, HPLC 2019, 16-20 June 2019, Milan, Italy.

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The binding of chiral drugs to plasma proteins is potentially enantioselective and frequently exhibits different pharmacological activities. Serum albumin is one of the most important proteins in human plasma and is commonly used as protein ligand in chiral capillary electrophoresis. Furthermore, human serum albumin has been reported as a stereoselective agent for studying enantioselective interactions. The estimation of binding constant highly contributes to enantiomeric-drugs development and quality control. In this study, mobility-shift affinity capillary electrophoresis was employed for the simultaneous enantiomeric separation and determination of binding constant. The enantiomeric separation was conducted at physiological pH of phosphate buffer containing human serum albumin as background electrolyte. Accordingly, a net negative charge of protein- ligand was obtained. Therefore, positively charged racemic drugs of amlodipine and verapamil were selected as chiral model compounds. Electrophoretic parameters of resolution and effective mobility were evaluated. Subsequently, association constant was determined through nonlinear regression of effective mobilities and total ligand concentrations. In the particular separation conditions, human serum albumin in the range of 30-110 μM displayed stereoselectivity to verapamil and amlodipine. As the sample was introduced into the capillary electrophoresis system, enantiomers bound the human serum albumin to different extents. The difference in apparent mobility shifts between enantiomers corresponds to the resolution of about 1.05-3.93. Moreover, R-(+)-verapamil proved to be bound stronger to human serum albumin compared with S-(-)- verapamil. The association constant of S-(-)-amlodipine was found to be higher compared to its antipode when applying the racemic mixture. In addition to this, a close agreement with the S-(-)-enantiomer was achieved.

Item Type: Conference or Workshop Item (Poster)
Subjects: R Medicine > RS Pharmacy and materia medica
Divisions: Faculty of Pharmacy > Department of Pharmacy
Depositing User: Ester Sri W. 196039
Date Deposited: 05 Jun 2023 04:57
Last Modified: 06 Jun 2023 04:09

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