TY - JOUR
T1 - Quantitation of 4-hydroxycyclophosphamide/aldophosphamide in whole blood
AU - Anderson, L. W.
AU - Ludeman, S. M.
AU - Colvin, O. M.
AU - Grochow, L. B.
AU - Strong, J. M.
N1 - Funding Information:
This investigation was supported in part by Public Health Service Grants 5-RO1-CA16783 (OMC) and 5-PO1-CA15396 (OMC) awarded by the National Cancer Institute (Department of Health and Human Services).
PY - 1995/5/19
Y1 - 1995/5/19
N2 - There is considerable interest in determining 4-hydroxycylcophosphamide/aldophosphamide (4-HO-CP/AP) blood levels in patients receiving the prodrug, cyclophosphamide (CP). Phosphoramide mustard (PM), the alkylating metabolite of CP, is relatively impermeable to cell membranes and it is generally believed that circulating intermediary metabolites, including aldophosphamide, the immediate precursor of PM, is transported by circulating blood to tumor tissue. Therefore, circulating 4-HO-CP/AP blood levels should more closely reflect the oncostatic and cytotoxic effects of CP than the parent drug. We have developed a gas chromatographic electron-impact mass spectrometric (GC-EIMS) method suitable for routine monitoring of 4-HO-CP/AP levels in whole blood over the range 0.085 μM (25 ng/ml) to 34 μM (10 μ/ml). The unstable metabolites were derivatized with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine-HCl to form a stable aldophosphamide oxime derivative (PBOX). [2H4]PBOX was used as an internal standard. For clinical samples, tubes were prepared prior to blood drawing, which contained the derivatizing reagent solution and the internal standard. These solutions were stable for up to 3 months when stored at room temperature. Following addition of blood to the reaction tubes, PBOX formation was rapid and the resulting derivative was stable under these conditions for up to 8 days at room temperature. Application of the method was demonstrated by quantitating 4-HO-CP/AP blood levels in patients receiving 4 g/m2 intravenous infusion of CP over a period of 90 min.
AB - There is considerable interest in determining 4-hydroxycylcophosphamide/aldophosphamide (4-HO-CP/AP) blood levels in patients receiving the prodrug, cyclophosphamide (CP). Phosphoramide mustard (PM), the alkylating metabolite of CP, is relatively impermeable to cell membranes and it is generally believed that circulating intermediary metabolites, including aldophosphamide, the immediate precursor of PM, is transported by circulating blood to tumor tissue. Therefore, circulating 4-HO-CP/AP blood levels should more closely reflect the oncostatic and cytotoxic effects of CP than the parent drug. We have developed a gas chromatographic electron-impact mass spectrometric (GC-EIMS) method suitable for routine monitoring of 4-HO-CP/AP levels in whole blood over the range 0.085 μM (25 ng/ml) to 34 μM (10 μ/ml). The unstable metabolites were derivatized with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine-HCl to form a stable aldophosphamide oxime derivative (PBOX). [2H4]PBOX was used as an internal standard. For clinical samples, tubes were prepared prior to blood drawing, which contained the derivatizing reagent solution and the internal standard. These solutions were stable for up to 3 months when stored at room temperature. Following addition of blood to the reaction tubes, PBOX formation was rapid and the resulting derivative was stable under these conditions for up to 8 days at room temperature. Application of the method was demonstrated by quantitating 4-HO-CP/AP blood levels in patients receiving 4 g/m2 intravenous infusion of CP over a period of 90 min.
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U2 - 10.1016/0378-4347(95)00036-I
DO - 10.1016/0378-4347(95)00036-I
M3 - Article
C2 - 7663697
AN - SCOPUS:0029031726
SN - 0378-4347
VL - 667
SP - 247
EP - 257
JO - Journal of Chromatography B: Biomedical Sciences and Applications
JF - Journal of Chromatography B: Biomedical Sciences and Applications
IS - 2
ER -