Q. Song et L. Putcha, Quantitation of promethazine and metabolites in urine samples using on-line solid-phase extraction and column-switching, J CHROMAT B, 763(1-2), 2001, pp. 9-20
A chromatographic method for the quantitation of promethazine (PMZ) and its
three metabolites in urine employing on-line solid-phase extraction and co
lumn-switching has been developed. The column-switching system described he
re uses an extraction column for the purification of PMZ and its metabolite
s from a urine matrix, The extraneous matrix interference was removed by fl
ushing the extraction column with a gradient elution. The analytes of inter
est were then eluted onto an analytical column for further chromatographic
separation using a mobile phase of greater solvent strength. This method is
specific and sensitive with a range of 3.75-1400 ng/ml for PMZ and 2.5-140
0 ng/ml for the metabolites promethazine sulfoxide, monodesmethyl promethaz
ine sulfoxide and monodesmethyl promethazine. The lower limits of quantitat
ion (LLOQ) were 3.75 ng/ml with less than 6.2% CV for PMZ and 2.50 ng/ml wi
th less than 11.5% CV for metabolites based on a signal-to-noise ratio of 1
0:1 or greater. The accuracy and precision were within +/- 11.8% in bias an
d not greater than 5.5% CV in intra- and inter-assay precision for PMZ and
metabolites. Method robustness was investigated using a Plackett-Bunnan exp
erimental design. The applicability of the analytical method for pharmacoki
netic studies in humans is illustrated. (C) 2001 Elsevier Science B.V. All
rights reserved.