• 한국임상약학회지
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• 제15권1호
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• pp.61-67
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• 2005

This study was designed to establish a strategy for the bioequivalence study of doxifluridine, an anticancer drug, in dogs instead of cancer patients. Although the results from animals may not occur in the same manner from human, those would be worth enough in terns of the bioequivalence. As for critically ill population such as cancer patients, bioequivalence studies in animals bring many advantages. Six healthy Beagle dogs were selected on the basis of hematology and blood chemistry test. After an over night fast, 200 mg of doxifluridine was orally administered, and blood was serially taken up to 12 hours. Plasma concentration of doxifluridine was measured using a newly validated bioanalytical method by a HPLC coupled tandem mass spectrometry. Time course of plasma doxifluridine concentration was analyzed with non-compartmental and compartmental approaches. Consequently, we represented hematology and blood chemistry database for the selection of healthy Beagle dogs, and suggested a sensitive and validated analytical method of doxifluridine, as well as a study design for the bioequivalence of doxifluridine in dogs.

• Journal of Pharmaceutical Investigation
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• 제37권3호
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• pp.179-186
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• 2007

A simple, sensitive and selective liquid chromatographic/tandem mass spectrometric method (LC-MS/MS) was developed and validated for doxifluridine and 5-fluorouracil (5-FU) quantification in dog heparinized plasma. Sample preparation was based on liquid-liquid extraction using a mixture of isopropanol/ethyl acetate (1/9 v/v) to extract doxifluridine, 5-FU and 5-chlorouracil (5-CU, an internal standard) from plasma. Chromatography was performed on a C-18 analytical column and the retention times were 2.7, 1.5 and 1.7 min for doxifluridine, 5-FU and 5-CU, respectively with shorter analysis time within 5 min than previously reported methods. The ionization was optimized using ESI negative mode and selectivity was achieved by tandem mass spectrometric analysis by multiple reaction monitoring (MRM) using the transformations of m/z 244.8>107.6, 129.0>42.0 and 144.9>42.1 for doxifluridine, 5-FU and 5-CU, respectively. The achieved low limit of quantification was 20.0 ng/mL and the assay exhibited linear range of 20-2000 ng/mL ($R^2>0.99957$ for doxifluridine and $R^2>0.99857$ for 5-FU), using $100{\mu}L$ of plasma. Accuracy and precision of quality control samples for both doxifluridine and 5-FU met KFDA and FDA Guidance criteria of 15% for accuracy with coefficients of variation less than 15%. This method demonstrated adequate sensitivity, specificity, accuracy, precision and stability to support the simultaneous analysis of doxifluridine and 5-FU in dog plasma samples in pharmacokinetic and bioequivalence studies.

• 약학회지
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• 제52권2호
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• pp.93-100
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• 2008

A liquid chromatographic method with tandom spectrometric detection (LC/MS/MS) for the simultaneous determination of doxifluridine and its active metabolite, 5-fluorouracil (5-FU) was developed over the concentration range of $5{\sim}2000$ ng/ml, respectively. Doxifluridine, 5-FU and internal standard, 5-chlorouracil (5-CU), were extracted from liver and intestine tissue via protein precipitation. Acetonitrile was used as the extraction solvent and the supernatant was evaporated and reconstructed in mobile phase. Optimum chromatographic separation was achieved on a Agilent Zorbax $C_{18}$ ($100\;mm{\times}2.1\;mm$, $3.5\;{\mu}m$) column with mobile phase run in isocratic with methanol : water (20 : 80, v/v). The flow rate was 0.2 ml/min with total cycle time of 5 min. The lower limit of quantification was validated at 5.0 ng/ml of liver and intestine tissue, for both doxifluridine and 5-FU, respectively. The intra-day and inter-day precision and accuracy of quality control (QC) samples were <11% coefficient of variation and <7% relative error from theoretical concentration for both analytes. In addition, the special designed stability study was performed, because the metabolism of doxifluridine occurs spontaneously even in ice bath for monkey liver. The stability of doxifluridine in liver and intestine of monkey and beagle dog was compared. It was found that bioanalytical validation could not be performed for the monkey liver; however, beagle dog's liver has relatively low speed of metabolism compared to monkey liver and instead of monkey liver, beagle dog's liver could be used for the validation. Bioanalytical validation could be performed in monkey intestine. Eventually, this developed method for liver and intestine will be useful in support of the toxicokinetic and pharmacokinetic studies of doxifluridine and 5-FU.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2235-2241
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• 2010

A reverse-phase HPLC method with detection by mass spectrometry is described for the simultaneous determination of doxifluridine and its two active metabolites, 5-fluorouracil (5-FU) and 5-fluorouridine (5-FUrd), in beagle dog plasma. The optimal chromatographic separation was achieved on a Waters $Xterra^{(R)}$ $C_{18}$ column ($4.6{\times}250\;mm$ i.d., $5\;{\mu}m$ particle size) with a mobile phase of 0.1% formic acid in a mixture of 99% methanol and purified water (99:1, v/v). The developed method was validated in beagle dog plasma with a lowest limit of quantification of $0.05\;{\mu}g/mL$ for both doxifluridine and 5-FU, and $0.2\;{\mu}g/mL$ for 5-FUrd. Doxifluridine and its two metabolites were stable under the analysis conditions, and intra- and inter-day accuracies exceeded 92.87%, with a precision variability ${\leq}11.34%$ for each analyte. Additionally, the method for quantifying doxifluridine and its two metabolites, 5-FU and 5-FUrd, in beagle dog plasma was applied successfully to the analysis of pharmacokinetic samples.

• 약학회지
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• 제51권3호
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• pp.174-178
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• 2007

A reverse-phase high performance liquid chromatography method with electrospray ionization and detection by mass spectrometry is described for the simultaneous determination of doxifluridine and its active metabolite 5-flu-orouracil (5-FU) in monkey serum. The method has greater sensitivity and simpler process than previous published methods with good accuracy and precision. A proper liquid/liquid extraction was used to extract simultaneously doxifluridine and 5-FU which has considerable difference in the polarity. Extracts were analyzed using LC/MS/MS providing a short analysis time within 5 min. The lower limit of quantification was validated at 10.0 ng/ml of serum for both doxifluridine and 5-FU. Accuracy and precision of quality control (QC) samples for both analytes met FDA Guidance criteria of ±15% for average QC accuracy with coefficients of variation less than 15%. The method will be applicable for preclinical studies and bioequivalence studies.

• 한국임상수의학회지
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• 제26권1호
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• pp.8-16
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• 2009

항암제에 의해 흰쥐에서 다형핵 백혈구(polymorphonuclear leukocytes, PMN) 의 활성산소종(reactive oxygen species, ROS)과 산화질소(nitric oxide, NO)의 생성변화에 대해 연구하였다. 최근 자극유도인자에 의한 PMN의 호흡방출은 protein kinase C (PKC)의 활성, inositol phosphate transduction pathway의 활성, 그리고 intracellular [$Ca^{2+}$]와 관계가 있다고 밝혀졌으며, 본 연구에서 사용된 항암제(cyclophosphamide, cisplatin, tamoxifen, doxifluridine)중 일부는 화학치료제로써 비특이적으로 면역을 억제하는데 사용되고 있다. 암 치료 시 백혈구의 방어기능에 미치는 영향을 연구하기 위한 목적으로 in vitro에서 각 항암제를 처리한 PMN을 배양하여 ROS와 NO의 생성변화와 이차적 신호전달계인 phospholipase C(PLC), D(PLD), PKC, tyrosine phosphorylation kinase (TPK)와 phosphatidylinositol-3 kinase의 억제율을 측정하였다. PMN에 각각cyclophosphamide, cisplatin, tamoxifen, doxifluridine을 short term(${\leq}4hrs$) 처리시, formylmethionyl-leucy1-phenylalanine (FMLP) 자극에 의해 호흡방출의 증가가 나타났다. 반면, long term (8hrs) 처리 시, ROS의 생성은concentration-dependent 방법으로 감소되었다.

• Molecular & Cellular Toxicology
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• 제3권2호
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• pp.137-144
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• 2007

The mechanism of cytotoxicity of doxifluridine, a prodrug fluorouracil (5-FU), has been ascribed to the misincorporation of fluoropyrimidine into RNA and DNA and to the inhibition of the nucleotide synthetic enzyme thymidylate synthase. Increased understanding of the mechanism of 5-FU has led to the development of strategies that increases its anticancer activity or predicts its sensitivity to patients. Using GeneChip?? Rhesus Macaque Genome arrays, we analyzed gene expression profiles of doxifluridine after two weeks repeated administration in cynomolgus monkey. Kegg pathway analysis suggested that cytoskeletal rearrangement and cell adhesion remodeling were commonly occurred in colon, jejunum, and liver. However, expression of genes encoding extracellular matrix was distinguished colon from others. In colon, COL6A2, COL18A1, ELN, and LAMA5 were over-expressed. In contrast, genes included in same category were down-regulated in jejunum and liver. Interestingly, MMP7 and TIMP1, the key enzymes responsible for ECM regulation, were overexpressed in colon. Several studies were reported that both gene reduced cell sensitivity to chemotherapy-induced apoptosis. Therefore, we suggest they have potential as target for modulation of 5-FU action. In addition, the expression of genes which have been previously known to involve in 5-FU pathway, were examined in three organs. Particularly, there were more remarkable changes in colon than in others. In colon, ECGF1, DYPD, TYMS, DHFR, FPGS, DUT, BCL2, BAX, and BAK1 except CAD were expressed in the direction that was good response to doxifluridine. These results may provide that colon is a prominent target of doxifluridine and transcriptional profiling is useful to find new targets affecting the response to the drug.