title: Electrokinetic chromatographic estimation of the enantioselective binding of nomifensine to human serum albumin and total plasma proteins.
abstract: 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.
authors.affiliation: Departamento de Química Analítica, Facultad de Farmacia, Universidad de Valencia, Burjassot, Valencia, Spain.
authors.forename: Lucía
authors.initials: L
authors.lastname: Asensi-Bernardi
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Martín-Biosca
authors.forename: Salvador
authors.initials: S
authors.lastname: Sagrado
authors.forename: María J
authors.initials: MJ
authors.lastname: Medina-Hernández
mesh_terms: D001798:Blood Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D006801:Humans; D009627:Nomifensine / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D012709:Serum Albumin / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D013237:Stereoisomerism
chemical_list: D001798:Blood Proteins; D012709:Serum Albumin; D009627:Nomifensine