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Simultaneous stereoselective analysis of naftopidil and O ‐desmethyl naftopidil enantiomers in rat feces using an online column‐switching high‐performance liquid chromatography method
Author(s) -
Zhang YunYing,
Liu XiaWen,
Zhu LiJun,
Yuan Mu
Publication year - 2014
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.3112
Subject(s) - chemistry , chromatography , desmethyl , enantiomer , analyte , stereoselectivity , high performance liquid chromatography , excretion , acetonitrile , extraction (chemistry) , stereochemistry , biochemistry , metabolite , catalysis
A novel online column‐switching chiral high‐performance liquid chromatography method was developed and validated for the simultaneous determination of naftopidil (NAF) and its O ‐desmethyl metabolites (DMN) enantiomers in rat feces. Direct and multiple injections of supernatant from rat feces homogenate were allowed through the column‐switching system. Analyte extraction was performed on the Capcell Pak mixed‐functional column by acetonitrile–phosphate buffer (pH 7.4; 10 m m ; 8:92, v/v) flowing at 1 mL/min. Separation of NAF and DMN enantiomers was achieved on the Chiralpak IA column by methanol–acetonitrile–acetate buffer (pH 5.3; 5 m m ; 45:33:22, v/v/v) flowing at 0.5 mL/min. The analytes were measured with a fluorescence detector at 290 nm ( λ ex ) and 340 nm ( λ em ). The validated method showed a good linearity [22.5–15,000 ng/mL for (+)‐/(−)‐NAF; 35–25,000 ng/mL for (+)‐/(−)‐DMN] and the lowest limits of quantification for NAF and DMN enantiomers were 22.5 and 35 ng/mL, respectively. Both intra‐ and inter‐day variations were <10%. The assay was successfully applied to the fecal excretion of NAF and DMN enantiomers in rat after single oral administration of (±)‐NAF. Nonstereoselective excretion of (+)‐ and (−)‐NAF was found in feces, while stereoselective excretion of (+)‐ and (−)‐DMN was observed with higher excretion levels of (+)‐DMN, indicating that there may exist stereoselective metabolism for NAF enantiomers. Copyright © 2014 John Wiley & Sons, Ltd.