Stereoselective determination of hydroxychloro-quine and its major metabolites in human urine by solid-phase microextraction and HPLC.

The enantioselective analysis of hydroxychloroquine (HCQ) and its major metabolites was achieved by HPLC and solid-phase microextraction. The chromatographic separation was performed on a Chiralcel OD-H column using hexane/methanol/ethanol (96:2:2, v/v/v) plus 0.2% diethylamine as the mobile phase, at the flow rate of 1.3 mL/min. The main extraction parameters were optimized. The best condition was achieved by the addition of 10% NaCl and 1 mL phosphate buffer 1 mol/L pH 11 to 3 mL human urine. The extraction was conducted for 40 min at 25 degrees C and the desorption time was 3 min using methanol (100%). PDMS-DVB 60 microm fiber was used in this study. The mean recoveries were 9.3, 9.2, and 14.4% for HCQ, desethylhydroxychloroquine (DHCQ), and desethylchloroquine (DCQ), respectively. The method was linear over the range of 50-1000 ng/mL for HCQ enantiomers and over the range of 42-416 ng/mL for DCQ and DHCQ enantiomers. Within-day and between-day precision and accuracy assays for HCQ and its metabolites were lower than 15%. The preliminary 48 h urinary excretion study performed in human urine showed to be stereoselective. The amount of (+)-(S)-enantiomer excreted was higher than its antipode.