Chiral capillary electrophoretic method for quantification of apomorphine.
A new method for chiral determination of apomorphine enantiomers was developed and validated. Seven different neutral and charged cyclodextrins were tested for enantioselectivity on R,S-apomorphine. Sulfobutylether-beta-cyclodextrin was found to offer the best resolution, but with this system, four peaks were detected from a solution of the two enantiomers, which was suggested to be the result of different forms of the complex between the selector and apomorphine. A complexation constant was estimated for a complex of 1:1 ratio for the second and the fourth peak, whereas the other two peaks were fitted to a model ratio of 1:2 (analyte-selector). To avoid this phenomenon, hydroxypropyl-beta-cyclodextrin was then chosen as the chiral selector. An optimisation study was performed on three factors: concentration of the chiral selector, pH of the buffer, and applied voltage. Optimum conditions were: 14 mM of hydroxypropyl-beta-cyclodextrin, pH 3.0, and 16 kV. UV detection was at 200 nm. The method was validated at the chosen conditions, offering a limit of detection of 0.2 microM and a limit of quantification of 0.5 microM. The validated method was applied for the determination of R,S-apomorphine in a transport study with an in vitro cell culture model of the intestinal mucosa (Caco-2).
Ha
Pham Thi Thanh
PT
Laboratory of Pharmaceutical Chemistry and Drug Analysis, Faculty of Pharmaceutical Sciences, 4 Van Evenstraat, B-3000 Leuven, Belgium.
Van Schepdael
Ann
A
Van Vaeck
Laurence
L
Augustijns
Patrick
P
Hoogmartens
Jos
J
D001058:Apomorphine / Q000032:analysis* / Q000378:metabolism; D001693:Biological Transport, Active; D018938:Caco-2 Cells; D003505:Cyclodextrins / Q000737:chemistry; D019075:Electrophoresis, Capillary; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D015203:Reproducibility of Results; D013237:Stereoisomerism
D003505:Cyclodextrins; D007202:Indicators and Reagents; D001058:Apomorphine