Enantioseparation of vesamicol in human serum by capillary electrophoresis with solid phase extraction and sulfated-beta-cyclodextrin

Chiral separation of 12 pairs of enantiomers by capillary electrophoresis using heptakis-(2,3-diacetyl-6-sulfato)-β-cyclodextrin as the chiral selector and the elucidation of the chiral recognition mechanism by computational methods

Chiral separation of 12 pairs of basic analyte enantiomers including oxybutynin, bambuterol, tradinterol, clenbuterol, clorprenaline, terbutaline, tulobuterol, citalopram, phencynonate, fexofenadine, salbutamol, and penehyclidine was conducted by capillary electrophoresis using a single-isomer anionic β-cyclodextrin derivative, heptakis-(2,3-diacetyl-6-sulfato)-β-cyclodextrin as the chiral selector. Parameters influencing separation were studied, including background electrolyte pH, heptakis-(2,3-diacetyl-6-sulfato)-β-cyclodextrin concentration, buffer concentration, and separation voltage. A background electrolyte consisting of 50 mM Tris-H₃ PO₄ and 6 mM heptakis-(2,3-diacetyl-6-sulfato)-β-cyclodextrin at pH 2.5 was found to be highly efficient for the separation of most enantiomers, with other conditions of normal polarity mode at 10 kV, detection wavelength of 210 nm using hydrodynamic injection for 3 s. Under the optimal conditions, baseline resolution (>1.50) for 11 pairs of enantiomers and somewhat lower resolution for penehyclidine enantiomers (1.17) were generated. Moreover, the possible mechanism of separation of clenbuterol, oxybutynin, salbutamol, and penehyclidine was investigated using a computational modeling method.

A validated LC method for the determination of vesamicol enantiomers in human plasma using vancomycin chiral stationary phase and solid phase extraction

An enantioseparation high performance liquid chromatographic (HPLC) method was developed and validated to determine D-(+)- and L-(-)-vesamicol in human plasma. The assay involved the use of a solid phase extraction for plasma sample clean up prior to HPLC analysis utilizing a C18 Bond-Elute column. Chromatographic resolution of the vesamicol enantiomers was performed on a vancomycin macrocyclic antibiotic chiral stationary phase (CSP) known as Chirobiotic V with a polar ionic mobile phase (PIM) consisting of methanol:glacial acetic acid:triethylamine (100:0.1:0.05 (v/v/v)) at a flow rate of 1.0 ml/min and UV detection set at 262 nm. All analyses were conducted at ambient temperature. The method was validated over the range of 1-20 microg/ml for each enantiomer concentration (R2>0.999). Recoveries for D-(+)- and L-(-)-vesamicol enantiomers were in the ranges of 96-105% at 3-16 microg/ml level. The method proved to be precise (within-run precision ranged from 1.3 to 2.7% and between-run precision ranged from 1.5 to 3.4%) and accurate (within-run accuracies ranged from 0.8 to 3.4% and between-run accuracies ranged from 1.7 to 5.0%). The limit of quantitation (LOQ) and limit of detection (LOD) for each enantiomer in human plasma were 1.0 and 0.5 microg/ml (S/N=3), respectively.