Lw. Anderson et al., QUANTITATION OF 4-HYDROXYCYCLOPHOSPHAMIDE ALDOPHOSPHAMIDE IN WHOLE-BLOOD, Journal of chromatography B. Biomedical applications, 667(2), 1995, pp. 247-257
Citations number
18
Categorie Soggetti
Chemistry Analytical
Journal title
Journal of chromatography B. Biomedical applications
There is considerable interest in determining 4-hydroxycylcophosphamid
e/aldophosphamide (4-HO-CP/AP) blood levels in patients receiving the
prodrug, cyclophosphamide (CP). Phosphoramide mustard (PM), the alkyla
ting metabolite of CP, is relatively impermeable to cell membranes and
it is generally believed that circulating intermediary metabolites, i
ncluding aldophosphamide, the immediate precursor of PM, is; transport
ed by circulating blood to tumor tissue. Therefore, circulating 4-HO-C
P/AP blood levels should more closely reflect the oncostatic and cytot
oxic effects of CP than the parent drug. We have developed a gas chrom
atographic electron-impact mass spectrometric (GC-EIMS) method suitabl
e for routine monitoring of 4-HO-CP/AP levels in whole blood over the
range 0.085 mu M (25 ng/ml) to 34 mu M (10 mu g/ml). The unstable meta
bolites were derivatized with O-(2,3,4,5,6-pentafluorobenzyl)hydroxyla
mine-HCl to form a stable aldophosphamide oxime derivative (PBOX). [H-
2(4)]PBOX was used as an internal standard. For clinical samples, tube
s were prepared prior to blood drawing, which contained the derivatizi
ng reagent solution and the internal standard. These solutions were st
able for up to 3 months when stored at room temperature. Following add
ition of blood to the reaction tubes, PBOX formation was rapid and the
resulting derivative was stable under these conditions for up to 8 da
ys at room temperature. Application of the method was demonstrated by
quantitating 4-HO-CP/AP blood levels in patients receiving 4 g/m(2) in
travenous infusion of CP over a period of 90 min.