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McDonald GB, Slattery JT, Bouvier ME, Ren S, Batchelder AL, Kalhorn TF, Schoch HG, Anasetti C, Gooley T. Cyclophosphamide metabolism, liver toxicity, and mortality following hematopoietic stem cell transplantation. Blood 2003; 101:2043-8. [PMID: 12406916 DOI: 10.1182/blood-2002-06-1860] [Citation(s) in RCA: 252] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Liver toxicity caused by high-dose myeloablative therapy leads to significant morbidity after hematopoietic cell transplantation. We examined the hypothesis that liver toxicity after cyclophosphamide and total body irradiation is related to cyclophosphamide through its metabolism to toxins. Cyclophosphamide was infused at 60 mg/kg over 1 to 2 hours on each of 2 consecutive days, followed by total body irradiation. Plasma was analyzed for cyclophosphamide and its major metabolites. Liver toxicity was scored by the development of sinusoidal obstruction syndrome (veno-occlusive disease) and by total serum bilirubin levels. The hazards of liver toxicity, nonrelapse mortality, tumor relapse, and survival were calculated using regression analysis that included exposure to cyclophosphamide metabolites (as the area under the curve). Of 147 patients, 23 (16%) developed moderate or severe sinusoidal obstruction syndrome. The median peak serum bilirubin level through day 20 was 2.6 mg/dL (range, 0.5-41.1 mg/dL). Metabolism of cyclophosphamide was highly variable, particularly for the metabolite o-carboxyethyl-phosphoramide mustard, whose area under the curve varied 16-fold. Exposure to this metabolite was statistically significantly related to sinusoidal obstruction syndrome, bilirubin elevation, nonrelapse mortality, and survival, after adjusting for age and irradiation dose. Patients in the highest quartile of o-carboxyethyl-phosphoramide mustard exposure had a 5.9-fold higher risk for nonrelapse mortality than did patients in the lowest quartile. Engraftment and tumor relapse were not statistically significantly related to cyclophosphamide metabolite exposure. Increased exposure to toxic metabolites of cyclophosphamide leads to increased liver toxicity and nonrelapse mortality and lower overall survival after hematopoietic cell transplantation.
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Gorbacheva VY, Kondratov RV, Zhang R, Cherukuri S, Gudkov AV, Takahashi JS, Antoch MP. Circadian sensitivity to the chemotherapeutic agent cyclophosphamide depends on the functional status of the CLOCK/BMAL1 transactivation complex. Proc Natl Acad Sci U S A 2005; 102:3407-12. [PMID: 15689397 PMCID: PMC546637 DOI: 10.1073/pnas.0409897102] [Citation(s) in RCA: 195] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The circadian clock controls many aspects of mammalian physiology, including responses to cancer therapy. We find that wild-type and circadian mutant mice demonstrate striking differences in their response to the anticancer drug cyclophosphamide (CY). While the sensitivity of wild-type mice varies greatly, depending on the time of drug administration, Clock mutant and Bmal1 knockout mice are highly sensitive to treatment at all times tested. On the contrary, mice with loss-of-function mutations in Cryptochrome (Cry1-/-Cry2-/- double knockouts) were more resistant to CY compared with their wild-type littermates. Thus, both time-of-day and allelic-dependent variations in response to chemotherapy correlate with the functional status of the circadian CLOCK/BMAL1 transactivation complex. Pharmacokinetic analysis of plasma concentration of different CY metabolites shows that, in contrast to the traditional view, circadian variations in drug sensitivity cannot be attributed to the changes in the rates of CY metabolic activation and/or detoxification. At the same time, mice of different circadian genotypes demonstrate significant differences in B cell responses to toxic CY metabolites: B cell survival/recovery rate was directly correlated with the in vivo drug sensitivity. Based on these results, we propose that the CLOCK/BMAL1 transcriptional complex affects the lethality of chemotherapeutic agents by modulating the survival of the target cells necessary for the viability of the organism.
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Klein NW, Vogler MA, Chatot CL, Pierro LJ. The use of cultured rat embryos to evaluate the teratogenic activity of serum: cadmium and cyclophosphamide. TERATOLOGY 1980; 21:199-208. [PMID: 7394724 DOI: 10.1002/tera.1420210211] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Head fold stage rat embryos were cultured for 48 hours in vitro on serum taken at various intervals from rats that had been injected ip with either cadmium or cyclophosphamide. Their response was compared to that of embryos cultured for the same period on control serum to which these substances were added directly. One and 4 hour sera from cadmium-injected rats (2.13 mgCd++/kg) were lethal. Eight hour serum allowed survival but embryos were exencephalic and contained reduced amounts of protein and DNA. The response to direct cadmium was characteristically different and was related to dosage and the extent to which zero-time embryos had progressed through the head fold stage. At 1.6 micro M, Cd++ susceptible embryos were hemorrhagic, though not exencephalic. One hour serum from rats given cyclophosphamide (180 mg/kg) was lethal. On 4 hour serum, embryos survived but were exencephalic and contained less protein and DNA than controls. Embryos were resistant to direct cyclophosphamide up to 800 micrograms per ml of medium. At this concentration, embryos appeared morphologically normal but contained reduced amounts of protein.
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Struck RF, Kirk MC, Witt MH, Laster WR. Isolation and mass spectral identification of blood metabolites of cyclophosphamide: evidence for phosphoramide mustard as the biologically active metabolite. BIOMEDICAL MASS SPECTROMETRY 1975; 2:46-52. [PMID: 1131393 DOI: 10.1002/bms.1200020109] [Citation(s) in RCA: 100] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Thin-layer chromatography and mass spectrometry were used to isolate and identify cyclophosphamide metabolites present in blood of mice. Blood was removed 5, 15, 30 and 45 minutes after intraperitoneal administration and extracted with chloroform followed by methanol. Thin-layer chromatography of the two extracts and the residual solid with or without prior methylation, collection of resulting alkylating components, determination of radioactivity and mass spectral analysis, served to identify cyclophosphamide, 4-ketocyclophosphamide, alcophosphamide, N-dechloroethylcyclophosphamide, carboxyphosphamide, phosphoramide mustard and nor-HN2. The absence of detectable levels of 4-hydroxycyclophosphamide or aldophosphamide in the blood of cyclophosphamide-treated mice suggests that cyclophosphamide is converted rapidly in the liver to carboxyphosphamide, 4-ketocyclophosphamide, phosphoramide mustard and nor-HN2. Direct administration of synthetic 4-hydroxycyclophosphamide to mice and extraction of blood with chloroform demonstrated the recovery of this metabolite in vivo. Analysis of extracts of blood from mice treated with phosphoramide mustard indicated the presence of nor-HN2, 3-(2-chloroethyl)-1,3-oxazolidin-2-one and unchanged drug. Consideration of blood levels, cytotoxicity and alkylating activity of metabolites identified, in or inferred from, this study, implicates phosphoramide mustard as a leading condidate for the biologically active form of cyclophosphamide.
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Pass GJ, Carrie D, Boylan M, Lorimore S, Wright E, Houston B, Henderson CJ, Wolf CR. Role of Hepatic Cytochrome P450s in the Pharmacokinetics and Toxicity of Cyclophosphamide: Studies with the Hepatic Cytochrome P450 Reductase Null Mouse. Cancer Res 2005; 65:4211-7. [PMID: 15899812 DOI: 10.1158/0008-5472.can-04-4103] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cyclophosphamide (CPA) is an anticancer prodrug that is dependent on cytochrome P450 (CYP) metabolism for its therapeutic effectiveness. In spite of the use of CPA in the clinic for over 50 years, little is known about the relationship between its toxicokinetics and therapeutic response. We have employed a powerful new model, the Hepatic Cytochrome P450 Reductase Null (HRN) mouse, which has almost no hepatic cytochrome P450 activity, to study the toxicokinetics of CPA and to establish in vivo the role of hepatic P450 metabolism in its pharmacokinetics. In HRN mice the in vitro metabolism and intrinsic clearance of CPA was over 6-fold lower than in wild-type animals. This change in CPA metabolism was also reflected in vivo, with a profound difference in the pharmacokinetics of both CPA and its metabolites. At a CPA dose of 100 mg/kg, the Cmax, plasma area under the curve (AUC) and half-life were increased by 2.6-, 6.2-, and 3.2-fold, respectively, in the HRN mice. Similar changes were also observed at a dose of 300 mg/kg. These data confirm that hepatic metabolism is the major route of CPA elimination and disposition. The primary metabolites of CPA, 4-hydroxycyclophosphamide (4-OH-CPA) and 3-dechloroethylcyclophosphamide, were still formed, but at altered rates in the HRN mice. At 100 mg/kg the t1/2 for 4-OH-CPA was increased 1.8-fold, the Cmax reduced 1.7-fold, and the AUC remained unchanged. This latter finding shows that P450-mediated oxidative metabolism is essential for the clearance of this compound. Toxicokinetic analysis of CPA-induced myelosuppression and granulocytopenia showed that at high doses (> or =100 mg/kg) there was no difference in myelotoxicity between the wild-type and HRN mice. However, at lower doses (< or =70 mg/kg) a significant difference was observed, with little toxicity seen in HRN mice but at least a 45% reduction in the bone marrow granulocyte population in wild-type mice. Meta-analysis of the toxicity experiments showed the myelotoxicity of CPA was found to be closely correlated with the Cmax of 4-OH-CPA (r2= 0.80, P = 0.002). As the therapeutic effectiveness of CPA has been linked to the AUC for 4-OH-CPA, the finding that 4-OH-CPA Cmax may determine its level of myelotoxicity indicates that the therapeutic index could be altered by changing the method of CPA administration. Furthermore, monitoring 4-OH-CPA Cmax may identify individuals at most risk of CPA side effects.
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Slattery JT, Kalhorn TF, McDonald GB, Lambert K, Buckner CD, Bensinger WI, Anasetti C, Appelbaum FR. Conditioning regimen-dependent disposition of cyclophosphamide and hydroxycyclophosphamide in human marrow transplantation patients. J Clin Oncol 1996; 14:1484-94. [PMID: 8622062 DOI: 10.1200/jco.1996.14.5.1484] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
PURPOSE The pharmacokinetics of cyclophosphamide (CY) and 4-hydroxycyclophosphamide (HCY) were studied in 14 patients being prepared for bone marrow transplantation with either busulfan (BU)/CY (n = 7) or CY/total-body irradiation (TBI) (n = 7) to determine whether exposure to CY and its proximate toxic metabolite HCY is modulated by other agents used in the preparative regimen. PATIENTS AND METHODS HCY was assayed by a new method that stabilized the metabolite at bedside. In BU/CY patients (who also received phenytoin), CY clearance was 112% greater (P = .0014), half-life 54% less (P = .0027), peak HCY concentration in plasma/CY dose 113% greater (P = .0006), and the ratio of area under the plasma concentration-time curves (AUCs) of HCY to CY 166% greater (P = .0116) than in CY/TBI patients. The ratio of the AUC of HCY/CY dose was 48% greater in BU/CY patients than in CY/TBI patients when one CY/TBI patient with an apparent impaired ability to eliminate HCY was excluded from analysis. In CY/TBI patients, there was an inverse correlation between the AUC of HCY and that of CY (R2 = .740, P = .028). Also, the ratio of the AUC of HCY/CY dose was correlated with the average concentration of BU at steady-state (Css, Bu) (R2 = .646, P = 0.29). Variability in CY and HCY pharmacokinetics among the 14 patients overall was pronounced, with the highest variability (15-fold) observed in the ratio of the AUC of HCY to that of CY. CONCLUSION Prior administration of BU and/or phenytoin significantly alters exposure to CY and HCY. Interpatient variability in HCY exposure at a given CY dose is substantial.
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Busse D, Busch FW, Bohnenstengel F, Eichelbaum M, Fischer P, Opalinska J, Schumacher K, Schweizer E, Kroemer HK. Dose escalation of cyclophosphamide in patients with breast cancer: consequences for pharmacokinetics and metabolism. J Clin Oncol 1997; 15:1885-96. [PMID: 9164199 DOI: 10.1200/jco.1997.15.5.1885] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
PURPOSE The alkylating anticancer agent cyclophosphamide (CP) is a prodrug that undergoes a complex metabolism in humans producing both active and inactive metabolites. In parallel, unchanged CP is excreted via the kidneys. The aim of this study was to investigate the influence of dose escalation on CP pharmacokinetics and relative contribution of activating and inactivating elimination pathways. PATIENTS AND METHODS Pharmacokinetics of CP were assessed in 12 patients with high-risk primary breast cancer who received an adjuvant chemotherapy regimen that included four courses of conventional-dose CP (500 mg/m2 over 1 hour every 3 weeks) followed by one final course of high-dose CP (100 mg/kg over 1 hour). Plasma concentrations of CP were analyzed by high-performance liquid chromatography (HPLC), 24-hour urinary concentrations of CP, and its inactive metabolites (carboxyphosphamide, dechloroethylcyclophosphamide [dechlorethylCP], ketocyclophosphamide [ketoCP]) were determined by 31-phosphorus-nuclear magnetic resonance (31P-NMR)-spectroscopy. RESULTS There was no difference in dose-corrected area under the concentration-time curve (AUC) (216 v 223 [mumol.h/[mL.g]), elimination half-life (4.8 v 4.8 hours), systemic clearance (79 v 77 mL/min) and volume of distribution (0.49 v 0.45 L/kg) of CP between conventional- and high-dose therapy, respectively. However, during high-dose chemotherapy, we observed a significant increase in the renal clearance of CP (15 v 23 mL/min; P < .01) and in the formation clearance of carboxyphosphamide (7 v 12 mL/min; P < .05) and dechloroethylCP (3.2 v 4.2 mL/min; P < .05), whereas metabolic clearance to ketoCP remained unchanged (1.3 v 1.2 mL/min). Consequently, metabolic clearance to the remaining (reactive) metabolites decreased from 52 to 38 mL/min (P < .001). The relative contribution of the different elimination pathways to overall clearance of CP demonstrated wide interindividual variability. CONCLUSION Overall pharmacokinetics of CP are apparently not affected during eightfold dose escalation. However, there is a shift in the relative contribution of different clearances to systemic CP clearance in favor of inactivating elimination pathways, thereby indicating saturation of bioactivating enzymes during dose escalation. Besides individual enzyme capacity, hydration and concomitant medication with dexamethasone modulated CP disposition.
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Powis G, Reece P, Ahmann DL, Ingle JN. Effect of body weight on the pharmacokinetics of cyclophosphamide in breast cancer patients. Cancer Chemother Pharmacol 1987; 20:219-22. [PMID: 3315280 DOI: 10.1007/bf00570489] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cyclophosphamide pharmacokinetics have been studied in 16 female patients with advanced breast cancer. The group included 7 patients who were greater than 20%, less than or equal to 30% over ideal body weight and 5 patients who were greater than 30% over ideal body weight. Cyclophosphamide plasma elimination half-lives ranged between 152 and 984 min (mean 457 min), the apparent volume of distribution between 19.1 and 62.3 1 (mean 36.1 1), and plasma clearance between 25.9 and 166.6 ml/min (mean 69.5 ml/min). There was a significant positive correlation (r = 0.624, P = 0.010) between body weight and plasma elimination half-life, and a significant negative correlation between body weight and cyclophosphamide clearance when normalized to body surface area (r = 0.578, P = 0.019) or normalized to ideal body weight (r = 0.531, P = 0.0345). The apparent volume of distribution did not correlate with body weight. The results show that cyclophosphamide disposition is altered in patients with increased body weight.
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Ma J, Waxman DJ. Modulation of the antitumor activity of metronomic cyclophosphamide by the angiogenesis inhibitor axitinib. Mol Cancer Ther 2008; 7:79-89. [PMID: 18202011 DOI: 10.1158/1535-7163.mct-07-0584] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The promising but still limited efficacy of angiogenesis inhibitors as monotherapies for cancer treatment indicates a need to integrate these agents into existing therapeutic regimens. Presently, we investigate the antitumor activity of the small-molecule angiogenesis inhibitor axitinib (AG-013736) and its potential for combination with metronomic cyclophosphamide. Axitinib significantly inhibited angiogenesis in rat 9L tumors grown s.c. in scid mice but only moderately delayed tumor growth. Combination of axitinib with metronomic cyclophosphamide fully blocked 9L tumor growth on initiation of drug treatment. In contrast, metronomic cyclophosphamide alone required multiple treatment cycles to halt tumor growth. However, in contrast to the substantial tumor regression that is ultimately induced by metronomic cyclophosphamide, the axitinib/cyclophosphamide combination was tumor growth static. Axitinib did not inhibit hepatic activation of cyclophosphamide or export of its activated metabolite, 4-hydroxy-cyclophosphamide (4-OH-CPA), to extrahepatic tissues; rather, axitinib selectively decreased 9L tumor uptake of 4-OH-CPA by 30% to 40%. The reduced tumor penetration of 4-OH-CPA was associated with a decrease in cyclophosphamide-induced tumor cell apoptosis and a block in the induction of the endogenous angiogenesis inhibitor thrombospondin-1 in tumor-associated host cells, which may contribute to the absence of tumor regression with the axitinib/cyclophosphamide combination. Finally, axitinib transiently increased 9L tumor cell apoptosis, indicating that its effects are not limited to the endothelial cell population. These findings highlight the multiple effects that may characterize antiangiogenic agent/metronomic chemotherapy combinations and suggest that careful optimization of drug scheduling and dosages will be required to maximize antitumor responses.
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Research Support, N.I.H., Extramural |
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MacGregor JT, Bishop ME, McNamee JP, Hayashi M, Asano N, Wakata A, Nakajima M, Saito J, Aidoo A, Moore MM, Dertinger SD. Flow cytometric analysis of micronuclei in peripheral blood reticulocytes: II. An efficient method of monitoring chromosomal damage in the rat. Toxicol Sci 2006; 94:92-107. [PMID: 16888079 DOI: 10.1093/toxsci/kfl076] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We have evaluated a flow cytometric method that allows assessment of micronucleated reticulocytes (MN-RETs) in microliter quantities of peripheral blood and compared results using this assay with those of established microscopic methods of scoring bone marrow and peripheral blood from rats treated with well-characterized genotoxic agents. Young reticulocytes (RETs) are labeled with FITC-anti-CD71 (transferrin receptor) and micronuclei with propidium iodide (with RNase treatment). Red blood cells parasitized with Plasmodia serve as a calibration standard for DNA content. Microscopic scoring used acridine orange (AO) staining of methanol-fixed slides or supravital AO staining. The effect of the rat spleen on the parameters evaluated was determined by comparing age- and sex-matched normal and splenectomized rats treated with cyclophosphamide, cis-platin, or vinblastine under treatment conditions that established a steady-state frequency of MN-RETs in the bone marrow and peripheral blood compartments. The data demonstrate the sensitivity and reproducibility of the flow cytometric assay in the Sprague-Dawley rat, and comparative studies using identical blinded samples at multiple laboratories show that inter- and intra-laboratory reproducibility is much higher with the flow method than with the microscopic methods currently employed for regulatory studies. A significant effect of splenic selection against genotoxicant-induced MN-RETs was observed with each of the three scoring methodologies, despite the fact that the flow and supravital AO techniques restrict analysis to the youngest fraction of RETs. The high precision of flow-based measurements also demonstrated a slight but statistically significant level of selection against spontaneously arising MN-RET. Despite these spleen effects, assay sensitivity for blood-based analyses was maintained by the flow method as it was shown to have superior counting statistics, lower variability, and higher sensitivity than manual scoring. The data suggest that flow cytometric assessment of micronucleus induction can be integrated into routine toxicity testing, eliminating the need for a separate bioassay.
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Validation Study |
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Yule SM, Boddy AV, Cole M, Price L, Wyllie R, Tasso MJ, Pearson AD, Idle JR. Cyclophosphamide pharmacokinetics in children. Br J Clin Pharmacol 1996; 41:13-19. [PMID: 8824688 DOI: 10.1111/j.1365-2125.1996.tb00153.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. Cyclophosphamide pharmacokinetics were measured in 38 children with cancer. 2. A high degree of inter-patient variation was seen in all pharmacokinetic parameters. Cyclophosphamide half-life varied between 1.1 and 16.8 h, clearance varied between 1.2 and 10.61 h-1 m-2 and volume of distribution varied between 0.26 and 1.48 1 kg-1. 3. The half-life of cyclophosphamide was prolonged at high dose levels (P = 0.008). 4. Children who had received prior treatment with dexamethasone showed a mean increase in clearance of 2.51 h-1 m-2 (P = 0.001) presumably as a result of CYP450 enzyme induction. 5. Treatment with allopurinol or chlorpromazine was associated with a significant increase in cyclophosphamide half-life (P < 0.001 in both cases). 6. Dose and concurrent treatment may influence cyclophosphamide metabolism in vivo and thus potentially alter the drugs therapeutic effect.
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Clinical Trial |
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Sandström M, Freijs A, Larsson R, Nygren P, Fjällskog ML, Bergh J, Karlsson MO. Lack of relationship between systemic exposure for the component drug of the fluorouracil, epirubicin, and 4-hydroxycyclophosphamide regimen in breast cancer patients. J Clin Oncol 1996; 14:1581-8. [PMID: 8622075 DOI: 10.1200/jco.1996.14.5.1581] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
PURPOSE The aim of this study was to investigate the covariance between the pharmacokinetics of the three components of the FEC regimen, epirubicin (EPI), fluorouracil (5-FU), and the cyclophosphamide (CP) metabolite 4-hydroxycyclophosphamide (4-OHCP), in breast cancer patients. PATIENTS AND METHODS Data from 21 women were collected over a total of 35 cycles. 5-FU (300 to 600 mg/m2) and CP (300 to 600 mg/m2) were administered as bolus injections, whereas EPI (15 to 60 mg/m2) was administered either as a bolus injection or as an infusion. The pharmacokinetics of the component drugs were monitored using a limited sampling scheme. Population pharmacokinetic models for each of the three drugs were developed using the program NONMEM. RESULTS The data for 5-FU were best described by a one-compartment model with nonlinear elimination, where the maximal rate of elimination (Vmax) and the concentration at which the elimination was half-maximal (Km) were 105 mg/L.h and 27 mg/L, respectively. EPI concentration-time profiles showed a triexponential decline, with a mean terminal half-life of 24 hours and a clearance (CL) of 59 L/h. The elimination of 4-OHCP was monoexponential, with a mean half-life of 7 hours. The interindividual coefficients of variation (CVs) in CL were 30%, 22%, and 41% for 5-FU, EPI, and 4-OHCP, respectively. The corresponding values for intrapatient course-to-course variability in CL were 11%, 8%, and 27%. No significant correlation in any of the pharmacokinetic parameters between the drugs was found. CONCLUSION Individualization of dosing of the FEC regimen using therapeutic drug monitoring and attempts to find concentration-response relationships may be successful, but requires that the exposure of all three drugs is considered simultaneously.
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Hassan M, Svensson US, Ljungman P, Björkstrand B, Olsson H, Bielenstein M, Abdel-Rehim M, Nilsson C, Johansson M, Karlsson MO. A mechanism-based pharmacokinetic-enzyme model for cyclophosphamide autoinduction in breast cancer patients. Br J Clin Pharmacol 1999; 48:669-77. [PMID: 10594468 PMCID: PMC2014348 DOI: 10.1046/j.1365-2125.1999.00090.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS This study investigated the pharmacokinetics of cyclophosphamide (CP) and its main metabolite 4-hydroxycyclophosphamide (4-OH-CP) in patients with breast cancer undergoing high dose chemotherapy prior to autologous stem cell transplantation. An enzyme turn-over model was also developed to study the time course of cyclophosphamide induction. METHODS Fourteen patients received a combination of CP (6 g m-2 ), thiotepum (500 mg m-2 ) and carboplatin (800 mg m-2 ) as a 96 h infusion. Plasma concentrations of CP and 4-OH-CP were determined with h.p.l.c. and a pharmacokinetic and enzyme turn-over model applied to data using NONMEM. RESULTS CP plasma concentrations were described by a two-compartment model with a noninducible and an inducible pathway, the latter forming 4-OH-CP. In the final enzyme model, CP affects the amount of enzymes by increasing the enzyme production rate. CP concentrations decreased during the infusion with no subsequent change in 4-OH-CP concentrations. CP inducible and noninducible clearance were estimated to 1.76 l h-1 (90% C.I. 0.92-2.58) and 1.14 l h-1 (0.31-1.85), respectively. The induction resulted in an approximately doubled CP clearance through the inducible pathway at the end of treatment. The model predicted the enzyme turn-over half-life to be 24 h. CONCLUSIONS The presented mechanism-based enzyme induction model where the pharmacokinetics of the inducer and the enzyme pool counterbalance each other successfully described CP autoinduction. It is reasonable to believe that CP affects its own elimination by increasing the enzyme production rate and thereby increasing the amount of enzyme by which CP is eliminated.
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D'Incalci M, Bolis G, Facchinetti T, Mangioni C, Morasca L, Morazzoni P, Salmona M. Decreased half life of cyclophosphamide in patients under continual treatment. Eur J Cancer 1979; 15:7-10. [PMID: 421718 DOI: 10.1016/0014-2964(79)90198-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Abstract
1. The pharmacokinetics of cyclophosphamide were investigated in cancer patients. The data can be characterized by a two-compartment open model. The half life of the elimination phase of the drug ranged between 3 and 11 hours.2. Extensive tubular reabsorption of the drug resulted in the excretion of only a small percentage of the administered dose. The mean renal clearance was 10.7 ml/minute.3. The calculated fraction of the dose of drug which was metabolized averaged 88%.
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letter |
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Ren S, Kalhorn TF, McDonald GB, Anasetti C, Appelbaum FR, Slattery JT. Pharmacokinetics of cyclophosphamide and its metabolites in bone marrow transplantation patients. Clin Pharmacol Ther 1998; 64:289-301. [PMID: 9757153 DOI: 10.1016/s0009-9236(98)90178-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To characterize the pharmacokinetics of cyclophosphamide and 5 of its metabolites in bone marrow transplant patients and to identify the mechanism of the increase in 4-hydroxycyclophosphamide area under the plasma concentration-time curve (AUC) from day 1 to day 2 of cyclophosphamide administration. METHODS Cyclophosphamide was administered by intravenous infusion (60 mg/kg over 1 hour, once a day) for 2 consecutive days to 18 patients. Cyclophosphamide and 4-hydroxycyclophosphamide concentration time data on day 1 and day 2 were fitted to a model to estimate 4-hydroxycyclophosphamide formation (CLf) and elimination (CLm) clearances. Erythrocyte aldehyde dehydrogenase-1 activity was measured ex vivo just before the first cyclophosphamide infusion was started (0 hours) and 24 hours after the second cyclophosphamide infusion (48 hours). RESULTS From day 1 to day 2, the AUC of cyclophosphamide, deschloroethyl cyclophosphamide and phosphoramide mustard decreased 24.8%, 51%, and 29.4% (P < .02), the AUC of 4-hydroxycyclophosphamide and carboxyethylphosphoramide mustard increased 54.7% and 25% (P < .01), whereas the AUC of phosphoramide mustard was not significantly changed (P > .3). The CLf of 4-hydroxycyclophosphamide increased 60% (P < .001), its CLm decreased 27.7% (P < .001), and the fraction of cyclophosphamide dose converted to 4-hydroxycyclophosphamide increased 16% (P < .001) from day 1 to day 2. The activity of patient erythrocyte aldehyde dehydrogenase-1 decreased 23.3% (P < .02) from 0 hours to 48 hours. CONCLUSIONS The AUC of 4-hydroxycyclophosphamide increased from day 1 to day 2 as a result of increased formation and decreased elimination clearances of 4-hydroxycyclophosphamide. Aldehyde dehydrogenase-1 activity appears to decline as a consequence of cyclophosphamide administration.
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Sánchez C, López-Jurado M, Aranda P, Llopis J. Plasma levels of copper, manganese and selenium in an adult population in southern Spain: influence of age, obesity and lifestyle factors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2010; 408:1014-1020. [PMID: 20018346 DOI: 10.1016/j.scitotenv.2009.11.041] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Revised: 11/13/2009] [Accepted: 11/20/2009] [Indexed: 05/28/2023]
Abstract
Copper, manganese and selenium are elements involved in protecting the body against oxidative stress. Determining their plasma level may contribute to assessing the health and nutritional status of populations. The aim of this study was to assess factors influencing copper, manganese and selenium plasma levels in an adult Mediterranean population and to identify groups at risk of deficiency. A cross-sectional survey was carried out in Andalusia, a region in southern Spain. Blood samples were obtained in a random subsample of 340 subjects. Food consumption was assessed by 48-h recall. Height, weight, skinfolds, waist and hip circumferences were measured. Copper, manganese and selenium were measured in plasma. Information about physical exercise, educational level, alcohol and smoking habits was obtained with a structured questionnaire. Plasma copper was found to be higher in women than among men. Hypocupraemia was found in 4.4% of the population, while 9.7% presented hypomanganesemia. Moreover, 86.5% presented plasma selenium values below 125microg/L (cutoff for optimal glutathione peroxidase activity). No association was found between plasma elements, anthropometric indices and lifestyle factors; there were tendencies, no more. Copper tended to decrease in obese and increase in sedentary, while selenium tended to decrease among smokers. Plasma Cu was positively correlated with the consumption of monounsaturated and polyunsaturated fats. Plasma Mn was directly correlated with the consumption of dairy products. Levels of Se were positively correlated with age, the consumption of fruit, vegetables, energy obtained from carbohydrates, and the consumption of fibre, and inversely correlated with the consumption of meat and sweets. Our results provide an estimate of the copper, manganese and selenium status in the adult population of southern Spain. The correlations found for Se suggest that there is a tendency for Se levels to be better maintained among the population that shows a stronger preference for the traditional diet.
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Pantarotto C, Bossi A, Belvedere G, Martini A, Donelli MG, Frigerio A. Quantitative GLC determination of cyclophosphamide and isophosphamide in biological specimens. J Pharm Sci 1974; 63:1554-8. [PMID: 4436788 DOI: 10.1002/jps.2600631014] [Citation(s) in RCA: 45] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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DiFrancesco R, Griggs JJ, Donnelly J, DiCenzo R. Simultaneous analysis of cyclophosphamide, doxorubicin and doxorubicinol by liquid chromatography coupled to tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 852:545-53. [PMID: 17379584 DOI: 10.1016/j.jchromb.2007.02.033] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Revised: 01/29/2007] [Accepted: 02/09/2007] [Indexed: 11/15/2022]
Abstract
A method for the simultaneous determination of cyclophosphamide (CP), doxorubicin (dox), and doxorubicinol (dol) was developed and validated to analyze 400 microL of plasma from patients receiving chemotherapeutic treatment with CP and dox. Final calibration ranges for the analytes were 0.440-60.0 microg/mL for cyclophosphamide, 7.20-984 ng/mL for dox and 3.04-104 ng/mL for dol. The samples were prepared using solid phase extraction and analyzed using a gradient separation over a Waters Symmetry C18, 2.1 by 30 mm (Milford, MA) column. Detection was achieved in positive mixed reaction monitoring mode on a triple quadrupole mass spectrometer.
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Dertinger SD, Bishop ME, McNamee JP, Hayashi M, Suzuki T, Asano N, Nakajima M, Saito J, Moore M, Torous DK, Macgregor JT. Flow Cytometric Analysis of Micronuclei in Peripheral Blood Reticulocytes: I. Intra- and Interlaboratory Comparison with Microscopic Scoring. Toxicol Sci 2006; 94:83-91. [PMID: 16888078 DOI: 10.1093/toxsci/kfl075] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Accumulating evidence suggests that reticulocytes (RETs) in the peripheral blood of rats may represent a suitable cell population for use in the micronucleus assay, despite the ability of the rat spleen to selectively remove micronucleated erythrocytes from the peripheral circulation. To evaluate the analytical performance of a previously described flow cytometric method (Torous et al., 2003, Toxicol. Sci. 74, 309-314) that may allow this assay to be conducted using peripheral blood in lieu of bone marrow sampling, we compared the sensitivity and performance characteristics of the flow cytometric technique with two established microscopy-based scoring methods. Peripheral blood samples from single Sprague-Dawley rats treated for 6 days with either vehicle or cyclophosphamide were prepared in replicate for scoring by the three methods at different laboratories. These blood-based measurements were compared to those derived from bone marrow specimens from the same animals, stained with acridine orange, and scored by microscopy. Through the analysis of replicate specimens, inter- and intralaboratory variability were evaluated for each method. Scoring reproducibility over time was also evaluated. These data support the premise that rat RETs harvested from peripheral blood are a suitable cell population to assess genotoxicant-induced micronucleus formation. The interlaboratory comparison provides evidence of the general robustness of the micronucleus endpoint using different analytical approaches. Furthermore, data presented herein demonstrate a clear advantage of flow cytometry-based scoring over microscopy-significantly lower inter- and intralaboratory variation and higher statistical sensitivity.
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Ma B, Yeo W, Hui P, Ho WM, Johnson PJ. Acute toxicity of adjuvant doxorubicin and cyclophosphamide for early breast cancer -- a retrospective review of Chinese patients and comparison with an historic Western series. Radiother Oncol 2002; 62:185-189. [PMID: 11937245 DOI: 10.1016/s0167-8140(02)00003-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A cohort of 85 Chinese breast cancer patients who received adjuvant chemotherapy with doxorubicin and cyclophosphamide was found to have a significantly higher incidence of grade 3 (n=44, 52%) and grade 4 (n=21, 25%) neutropenia when compared with an historic Western cohort. Also noted was a higher incidence of hepatotoxicity (n=8, 9%). When compared to Caucasian patients, the higher myelotoxicity in our patients may be related to ethnic variation in susceptibility to chemotherapy-related toxicity, lower body mass index with higher percentage of body fat composition, and the popular practice of concurrent alternative medicine during chemotherapy. The higher incidence of hepatoxicity was possibly associated with endemic chronic hepatitis B infection in this geographical area.
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Huitema AD, Kerbusch T, Tibben MM, Rodenhuis S, Beijnen JH. Reduction of cyclophosphamide bioactivation by thioTEPA: critical sequence-dependency in high-dose chemotherapy regimens. Cancer Chemother Pharmacol 2000; 46:119-27. [PMID: 10972481 DOI: 10.1007/s002800000132] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE Cyclophosphamide and thioTEPA are frequently used simultaneously in high-dose chemotherapy regimens. During a pharmacokinetic study of 31 courses in 20 patients of cyclophosphamide and its activated metabolite 4-hydroxycyclophosphamide given in the combination cyclophosphamide thioTEPA carboplatin, a sharp decrease in 4-hydroxycyclophosphamide concentration was observed immediately after the start of the thioTEPA infusion. A drug-drug interaction was suspected. This putative interaction was investigated in this study. METHODS Possible sequence dependency, due to inhibition of the formation of 4-hydroxycyclophosphamide by thioTEPA, was investigated by altering the sequence of infusion in three patients (four courses) receiving high-dose chemotherapy with cyclophosphamide (1,000 or 1,500 mg/m2 per day), thioTEPA (80 or 120 mg/m2 per day) and carboplatin (265 or 400 mg/m2 per day) in short infusions for four consecutive days. The pharmacokinetics of cyclophosphamide and 4-hydroxycyclophosphamide were established. Possible inhibition of the metabolism of cyclophosphamide and thioTEPA was investigated in human microsomes. RESULTS A striking sequence dependency of the pharmacokinetics of 4-hydroxycyclophosphamide was observed. Administration of thioTEPA 1 h prior to cyclophosphamide resulted in decreased Cmax (-62%) and AUC (-26%) values of 4-hydroxycyclophosphamide compared to those of thioTEPA administered 1 h after cyclophosphamide. In human microsomes an inhibition of the conversion of cyclophosphamide to 4-hydroxycyclophosphamide by thioTEPA was observed at clinically relevant concentrations with an IC50 of 23 microM. No inhibition of the formation of TEPA by cyclophosphamide was observed. CONCLUSIONS ThioTEPA strongly inhibits the bioactivation of cyclophosphamide and this may decrease both efficacy and toxicity. Our results seriously question the practice of the simultaneous continuous infusion of cyclophosphamide and thioTEPA and suggest that the sequencing and scheduling of these two agents in high-dose chemotherapy regimens may be of critical importance.
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Baumann F, Lorenz C, Jaehde U, Preiss R. Determination of cyclophosphamide and its metabolites in human plasma by high-performance liquid chromatography-mass spectrometry. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1999; 729:297-305. [PMID: 10410955 DOI: 10.1016/s0378-4347(99)00178-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A sensitive HPLC-MS method was developed for the simultaneous determination of cyclophosphamide and its metabolites 4-hydroxycyclophosphamide (aldocyclophosphamide), 4-ketocyclophosphamide, caboxyphosphamide and 3-dechloroethylifosfamide in human plasma. 4-Hydroxycyclophosphamide was converted with methylhydroxylamine to the stable methyloxime form. We used a solid-phase extraction with C18 cartridges followed by HPLC-MS with the single mass spectrometer SSQ 7000 of Finnigan. The limits of detection were 15 ng/ml for cyclophosphamide, 3-dechloroethylifosfamide and ketocyclophosphamide in each case and 30 ng/ml for carboxyphosphamide and 4-hydroxycyclophosphamide, respectively. First results of pharmacokinetics are shown.
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de Jonge ME, Mathôt RAA, Dalesio O, Huitema ADR, Rodenhuis S, Beijnen JH. Relationship between irreversible alopecia and exposure to cyclophosphamide, thiotepa and carboplatin (CTC) in high-dose chemotherapy. Bone Marrow Transplant 2002; 30:593-7. [PMID: 12407434 DOI: 10.1038/sj.bmt.1703695] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2002] [Accepted: 06/26/2002] [Indexed: 11/10/2022]
Abstract
Reversible alopecia is a commonly observed, important and distressing complication of chemotherapy. Permanent alopecia, however, is rare after standard-dose therapy, but has occasionally been observed after high-dose chemotherapy with cyclophosphamide, thiotepa and carboplatin (CTC). We evaluated the relationships between total exposure to these three compounds and their different metabolites in the high-dose CTC regimen, and the subsequent development of irreversible alopecia. Twenty-four patients received two or three courses of high-dose CTC, each followed by peripheral blood progenitor cell transplantation. Plasma levels of cyclophosphamide, its active metabolite 4-hydroxycyclophosphamide, thiotepa, its active metabolite tepa, and carboplatin were determined, and the area-under-the-plasma concentration-versus-time curves (AUC) of the compounds were calculated. Eight of the 24 patients included in the study developed permanent alopecia, while seven had normal hair regrowth and nine patients developed incomplete and/or thin hair regrowth. The carboplatin AUC and the summed AUC of thiotepa and tepa were both significantly associated with increasing irreversibility of hair loss. These results suggest that high exposure to carboplatin and the sum of the thiotepa and tepa exposure may lead to the development of permanent alopecia. This knowledge could guide therapeutic drug monitoring in order to prevent the occurrence of permanent alopecia and thereby improve the patients' quality of life.
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de Jonge ME, van Dam SM, Hillebrand MJX, Rosing H, Huitema ADR, Rodenhuis S, Beijnen JH. Simultaneous quantification of cyclophosphamide, 4-hydroxycyclophosphamide, N,N',N"-triethylenethiophosphoramide (thiotepa) and N,N',N"-triethylenephosphoramide (tepa) in human plasma by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2004; 39:262-271. [PMID: 15039933 DOI: 10.1002/jms.570] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The alkylating agents cyclophosphamide (CP) and N, N', N"-triethylenethiophosphoramide (thiotepa) are often co-administered in high-dose chemotherapy regimens. Since these regimens can be complicated by the occurrence of severe and sometimes life-threatening toxicities, pharmacokinetically guided administration of these compounds, to reduce variability in exposure, may lead to improved tolerability. For rapid dose adaptations during a chemotherapy course, we have developed and validated an assay, using liquid chromatography coupled with electrospray tandem mass spectrometry (LC/MS/MS), for the routine quantification of CP, thiotepa and their respective active metabolites 4-hydroxycyclophosphamide (4OHCP) and N, N', N"-triethylenephosphoramide (tepa) in plasma. Because of the instability of 4OHCP in plasma, the compound is derivatized with semicarbazide (SCZ) immediately after sample collection and quantified as 4OHCP-SCZ. Sample pretreatment consisted of protein precipitation with a mixture of methanol and acetronitrile using 100 microl of plasma. Chromatographic separation was performed on an Zorbax Extend C18 column (150 x 2.1 mm i.d., particle size 5 microm), with a quick gradient using 1 mM ammonia solution and acetonitrile, at a flow-rate of 0.4 ml min(-1). The analytical run time was 10 min. The triple quadrupole mass spectrometer was operating in the positive ion mode and multiple reaction monitoring was used for drug quantification. The method was validated over the concentration ranges 200-40,000 ng ml(-1) for CP, 50-5000 ng ml(-1) for 4OHCP-SCZ and 5-2500 ng ml(-1) for thiotepa and tepa, using 100 microl of human plasma. These dynamic concentration ranges proved to be relevant in daily practice. Hexamethylphosphoramide was used as an internal standard. The coefficients of variation were <12% for both intra-day and inter-day precisions for each compound. Mean accuracies were also between the designated limits (+/- 15%). This robust and rapid LC/MS/MS assay is now successfully applied for routine therapeutic drug monitoring of CP, thiotepa and their metabolites in our hospital.
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