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Study of interaction between drug enantiomers and human serum albumin by flow injection‐capillary electrophoresis frontal analysis
Author(s) -
Liu Xiumei,
Chen Xingguo,
Yue Yuanyuan,
Zhang Jingshu,
Song Yuqin
Publication year - 2008
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200700748
Subject(s) - chemistry , human serum albumin , enantiomer , chromatography , ionic strength , capillary electrophoresis , ketoprofen , binding site , serum albumin , analytical chemistry (journal) , stereochemistry , biochemistry , aqueous solution , organic chemistry
Flow injection (FI)‐CE coupled with frontal analysis (FA) was applied to the study of stereoselectivity binding of amlodipine (AL) to HSA. Under protein‐drug binding equilibrium, the unbound concentrations of drug enantiomers were measured by plateau height. The stereoselectivity of AL binding to HSA was proved by the different free fractions of two enantiomers. In physiological phosphate solution (pH 7.4, ionic strength 0.17) when 200 μM (±)AL was equilibrated with 300 μM HSA, the concentration of unbound R ‐AL was about 1.5 times higher than that of its antipode. The binding constants of two enantiomers, K R ‐AL and K S ‐AL , were 9910–11200 and 90200–104000 M −1 , respectively. The results obtained by the method were compared with those determined by conventional equilibrium dialysis (ED)‐CE and fluorescence spectra. Hydroxypropyl‐β‐CD (HP‐β‐CD) (10 mM) was used as a chiral selector in pH 3.7 phosphate buffer. L ‐Tryptophan ( L ‐try) and ketoprofen (Ket) were used as displacement reagents to investigate the binding sites of AL to HSA. A binding synergism effect between hydrochlorothiazide (QL) and AL was observed and the results suggested that QL can destroy binding equilibrium of R ‐AL and S ‐AL toward HSA and they can occupy the same binding site of HSA (site I). The reproducibility was confirmed by RSD (RSD<1.5%) of the plateau height determined by FI‐CE frontal analysis (FI‐CE‐FA). The FI‐CE‐FA was a good method to study protein–drug interaction.