Enantioseparation and Determination of Sulcoanzole Enantiomers in Rat Plasma and Tissues by Chiral HPLC-ESI-MS/MS Method Coupled with SPE Procedure and Its Application to the Studies on Stereoselective Pharmacokinetics and Tissue Distribution

Abstract

In our research, a novel reverse phase mode high performance liquid chromatography-electrospray ionization coupled with tandem mass spectrometry (HPLC-ESI-MS/MS) method for the rapid and sensitive enantioselective analysis of sulconazole in rat plasma and tissues was developed and validated. A newly developed solid phase extraction (SPE) procedure using C18 cartridge was selected for the extraction of sulconazole and internal standard (IS, ornidazole) from plasma and tissues. The excellent enantioseparation of sulconazole enantiomers was achieved on a Chiralpak IC column by using acetonitrile/5 mM aqueous ammonium acetate (90:10, v/v) as a mobile phase, and the detection of the targeted compounds and IS was performed on a multiple reaction monitoring (MRM) mode with positive electrospray ionization source. Using the measured Electronic Circular Dichroism (ECD) spectrum combined with the calculated ECD spectrum, the absolute configuration of sulconazole enantiomers was confirmed and was used to identification of the elution peak order. The S-(+)-sulconazole was first eluted. After comprehensive validation following the FDA-guideline, the method was linear over concentration ranges of 1.00-500.0 ng/mL (R2>0.991) for each enantiomer. The mean recoveries of S-(+)- and R-(-)-sulconazole at three spiked levels ranged from 88.7-102.5%, the intra- and inter-day relative standard deviation (RSD) were limited within 10.3%. The established method was successfully applied to the study on stereoselective pharmacokinetics and tissue distribution in Sprague-Dawley rats after transdermal administration of rac-sulconazole spray. It should be noted that this is the first report regarding the stereospecific study of sulconazole enantiomers in vivo.