Tropical Journal of Pharmaceutical Research
Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, Nigeria
Vol. 13, No. 2, 2014, pp. 281-286
Bioline Code: pr14041
Full paper language: English
Document type: Research Article
Document available free of charge
Tropical Journal of Pharmaceutical Research, Vol. 13, No. 2, 2014, pp. 281-286
© Copyright 2014 - Tropical Journal of Pharmaceutical Research
Sensitive and Selective Reversed-Phase High Performance Liquid Chromatographic-UV Spectrophotometric Determination of Dextromethorphan and its CYP2D6 Mediated Metabolite, Dextrorphan in Human Urine|
Ebeshi, Benjamin U.; Obodozie, Obiageri O. & Bolaji, Oluseye O.
Purpose: To develop a simple, sensitive and selective method for the determination of
dextromethorphan and its metabolite, dextrophan in human urine using reversed-phase high
performance liquid chromatography with UV-spectrophotometric detection (RP-HPLC-UV).
Methods: Pre-column sample clean-up was carried out by liquid-liquid extraction of the analytes with
chloroform: isopropanol (70:30) solution after alkalization of 1000 μL sample and spiking of internal
standard, morphine. The samples were chromatographed in a reversed-phase (C-18) ultra sphere silica
(5μm particle size and 250 x 4.6 mm I.D). The mobile phase consisted of methanol: acetonitrile: 0.5%
w/v ammonium acetate (10:10:80) adjusted to pH 2.8 with orthophosphoric acid and pumped through
the column at 1ml/min flow rate. The analytical method was validated for accuracy and precision as well
as the recovery of the analytes, dextromethorphan and its metabolite, dextrophan over the
concentration range of 0.20 to 5.0μg/ml.
Results: The standard curves were linear over the concentration range of 0.2 to 5.0μg/ml for
dextromethorphan and dextrorphan. The regression coefficients (R2) of the analytes were >0.99. The
method was reproducible with coefficient of variation for the analytes being < 10 %. Dextromethorphan
was well resolved from its metabolite, dextrorphan and the internal standard, morphine. The limits of
detection of dextromethorphan and dextrorphan were 50ng/ml and the recoveries and accuracies were
greater than 85 and 90 %, respectively.
Conclusion: The analytical assay method exhibits good precision and selectivity and it was applied to
the analysis of dextromethorphan and dextrorphan in urine for the assessment of CYP2D6 activity.
Dextromethorphan; Dextrophan; Reversed-phase high performance liquid chromatography; CYP2D6 activity; Human urine
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