Cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) method was developed for simultaneous enantioseparation of three imidazole drugs namely tioconazole, isoconazole and fenticonazole. Three easily available and inexpensive cyclodextrins namely 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), 2-hydroxypropyl-γ-cyclodextrin (HP-γ-CD) and heptakis(2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD) were evaluated to discriminate the six stereoisomers of the drugs. However, none of the three CDs gave a complete enantioseparation of the drugs. Effective enantioseparation of tioconazole, isoconazole and fenticonazole was achieved using a combination of 35 mM HP-γ-CD and 10 mM DM-β-CD as chiral selectors. The best separation using both HP-γ-CD and DM-β-CD (35 mM:10 mM) as chiral selectors were accomplished in background electrolyte (BGE) containing 35 mM phosphate buffer (pH 7.0), 50 mM sodium dodecyl sulfate (SDS) and 15% (v/v) acetonitrile at 27 kV and 30 °C with all peaks resolved in less than 15 min with resolutions, Rs 1.90-27.22 and peak efficiencies, N > 180 000. The developed method was linear over the concentration range of 25-200 mg l(-1) (r(2) > 0.998) and the detection limits (S/N = 3) of the three imidazole drugs were found to be 2.7-7.7 mg l(-1). The CD-MEKC method was successfully applied to the determination of the three imidazole drugs in spiked human urine sample and commercial cream formulation of tioconazole and isoconazole with good recovery (93.6-106.2%) and good RSDs ranging from 2.30-6.8%.
BACKGROUND: We previously reported on a Swedish patient with Behçet's disease (BD) who was an ultra-rapid metaboliser of drugs catalysed by CYP2C9. Was this extreme metabolism caused by the disease?
AIM: This study aims to compare the genotype/phenotype of CYP2C9 in patients with BD and healthy subjects. As the occurrence of BD is high in Turkey, all subjects were recruited from this country.
METHODS: Genotyping of CYP2C9 was performed using standard PCR-RFLP and allele-specific PCR methods. Phenotyping of CYP2C9 was performed by administration of a 50-mg single oral dose of losartan and by calculating the urinary metabolic ratio (MR) of probe drug to its metabolite E-3174. Quantitation was performed by HPLC.
RESULTS: The frequency of CYP2C9*2 and *3 was not significantly different between the Behçet's disease patients (12.5 and 8.7%) and the healthy subjects (8.9 and 8.2%). The geometric mean losartan MR was higher in the 52 patients (1.75) than in the 96 healthy subjects (1.02) (p = 0.002; t-test). Within the genotypes *1/*1, there was a significant difference of MR between patients and healthy subjects (P = 0.006). All but three of the Behçet's disease patients were treated with colchicine. In nine subsequent patients, we found no significant effect of 2 weeks of treatment with colchicine on the CYP2C9 MR.
CONCLUSION: Contrary to expectation, the CYP2C9 activity was lower in Turkish BD patients compared to healthy subjects. As this seems not to be due to colchicine treatment, our hypothesis is that inflammation related to BD might have caused the down-regulation of the CYP2C9 activity due to immune cytokine reactions. The ultra-rapid metabolism of CYP2C9 substrate drugs in the Swedish patient was not due to her BD.