HPLC Analysis of Amlodipine and Plasma Protein Binding of its Enantiomers

Vladimír Kubíček (kubicek@faf.cuni.cz), Alice Lázníčková

Department of Biophysics and Physical Chemistry, Research Centre LN00B125, Charles University in Prague, Faculty of Pharmacy in Hradec Králové, Czech Republic

Summary

Protein binding of amlodipine enantiomers in human and rat plasma was studied by equilibrium dialysis and achiral HPLC. Binding of amlodipine to plasma proteins of both species was relatively high (> 92 %). Significantly higher binding of S(-) enantiomer in comparison to R(+) one was determined. At the drug concentration of 10 μg/ml the main binding protein for amlodipine in human plasma was albumin. On the other hand, α₁-acid glycoprotein was responsible for differences in the protein binding of the individual enantiomers.