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Electrokinetic chromatographic estimation of the enantioselective binding of nomifensine to human serum albumin and total plasma proteins
Author(s) -
AsensiBernardi Lucía,
MartínBiosca Yolanda,
Sagrado Salvador,
MedinaHernández María J.
Publication year - 2012
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.2704
Subject(s) - chemistry , nomifensine , chromatography , enantiomer , human serum albumin , ultrafiltration (renal) , blood proteins , electrokinetic phenomena , bovine serum albumin , free fraction , serum albumin , plasma protein binding , albumin , stereochemistry , biochemistry , dopaminergic , neuroscience , dopamine , biology
This report is the first evidence of enantioselective binding of nomifensine to human serum albumin (HSA) and plasma proteins. The overall process with HSA included: (i) consistent experimental design along two independent sessions; (ii) incubation of nomifensine–HSA designed mixtures; (iii) ultrafiltration for separating the unbound enantiomers fraction; (iv) electrokinetic chromatography (EKC) using heptakis‐2,3,6‐tri‐ O ‐methyl‐ β ‐cyclodextrin as chiral selector to provide experimental data for enantiomers (first, E1, and second, E2, eluted ones); and (v) a recent direct equation allowing univariate tests and robust statistics to provide consistent parameters and uncertainty. A significant enantioselectivity to HSA (2.7 ± 0.1) was encountered, related to a 1:1 stoichiometry and log affinity constants of 3.24 ± 0.10 and 3.67 ± 0.08 for E1 and E2, respectively. The protein binding ( PB ) estimated at physiological concentration levels was 40 ± 5 and 63 ± 4% for E1 and E2, respectively. The use of synthetic human sera allowed in vitro estimation of the total plasma PB for the racemate (61 ± 5%; coincident with in vivo values), and its enantiomers (58 ± 7 and 64 ± 4% for E1 and E2, respectively). Comparison allowed the relative importance of HSA respect to other plasma proteins for binding nomifensine to be established. Copyright © 2012 John Wiley & Sons, Ltd.