Simple determination of capecitabine and its metabolites by liquid chromatography with ultraviolet detection in a single injection

Simultaneous Quantification of a Neoadjuvant Treatment Used in Locally Advanced Breast Cancer Using an Eco-Friendly UPLC-MS/MS Method: A Pharmacokinetic Study in Rat Plasma

Recently, neoadjuvant treatment has turned out to be a feasible alternative for individuals suffering from locally advanced breast cancer. The neoadjuvant therapy is a type of chemotherapy that is given either before or after surgeries to diminish a tumor and minimize the likelihood of recurrence. This article demonstrates the development of a unique bioanalytical validated sensitive method by means of an ultra high performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) approach for the concurrent estimation of neoadjuvant treatments including 5-Fluorouracil, Doxorubicin, and Capecitabine in rat plasma. Samples were prepared using the fine minor QuEChERS process and analyzed using a Shimadzu-C18 column via an isocratic separation. Acetonitrile:water in the ratio of (30:70) (both containing 0.1 percent formic acid v/v) was the mobile phase employed at a flow rate of 0.20 mL/min. At concentrations of 50.00–500.00 ng/mL for 5-Fluorouracil, 25.00–500.00 ng/mL for Doxorubicin, and 5.00–100.00 ng/mL for Capecitabine, the procedure was shown to be linear. The limit of detection (LOD) was assessed in ng/mL and varied from 1.33 to 13.50. Relative standard deviations for precision were below 2.47 percent over the whole concentration range. For all analytes, the average recovery rate varied from 73.79 to 116.98 percent. A preliminary pharmacokinetic study was successfully performed in real rats to evaluate the procedure efficiency.

Sorption of pharmaceuticals on the surface of microplastics

The presence of both pollutants: microplastics and pharmaceutical residues in various environmental compartments is an issue of increasing concern. Available literature data indicates that microplastics can affect the environmental distribution and transport of e.g. persistent organic pollutants (POPs) through sorption interactions, concentrating them at a given point and thus influencing the environmental risks represented by the sorbent and sorbate pair. Therefore, their potential to change the fate of other contaminants in the environment, such as pharmaceuticals, is worth investigating. The aim of this study was to evaluate the sorption capacity of nine pharmaceuticals, commonly used in human and veterinary medicine, which constitute known ubiquitous water pollutants: enrofloxacin (ENR), ciprofloxacin (CIP), norfloxacin (NOR), 5-fluorouracil (5-FU), methotrexate (MET), flubendazole (FLU), fenbendazole (FEN), propranolol (PRO) and nadolol (NAD), on the surface of the most often identified microscopic plastic particles in the aquatic environment, i.e. polypropylene (PP), low density polyethylene (LD-PE), high density polyethylene (HD-PE) and polyvinyl chloride (PVC). The obtained results suggest a complex nature of sorption, including both hydrophobic and electrostatic interactions. However, since the ionic strength of the medium was found to be a significant factor influencing the sorption potential, minute interactions are observed in conditions common for the natural environment.

Genetic influence of DPYD*9A polymorphism on plasma levels of 5-fluorouracil and subsequent toxicity after oral administration of capecitabine in colorectal cancer patients of South Indian origin

OBJECTIVES

High interindividual variability was reported with capecitabine toxicities among colorectal cancer (CRC) patients. DPYD*9A polymorphism was reported responsible for grade 3 or 4 toxicities. Finding the phenotypic association between DPYD*9A polymorphism and 5-fluorouracil (5-FU) plasma levels will give a better prediction for toxicity susceptibility.

METHODS

A total of 145 CRC patients were included in the final analysis. Each patient received capecitabine of 1,000 mg/m² twice daily for the first 14 days of a 21 day cycle. 5-FU levels were measured at two-time points 2 and 3 h post capecitabine administration across the 1st and 4th cycles of chemotherapy. 5-FU levels were measured using liquid chromatography and tandem mass spectrometry (LC-MS/MS). Genotyping analysis was done by real-time PCR (RT-PCR).

RESULTS

The mean 5-FU drug levels measured during the 1st cycle at time points 2 and 3 h were found to be 267 ng/mL ± (29) and 124 ng/mL ± (22) respectively. Whereas, the observed 5-FU levels in the 4th cycle were 275 ng/mL ± (28) and 130 ng/mL ± (26) respectively. Patients with 5-FU levels in the range of 281-320 and 141-160 ng/mL at 2 and 3 h respectively showed a higher risk for the hand-foot syndrome (HFS) and thrombocytopenia. No association was found between DPYD*9A polymorphism and 5-FU drug levels measured at time point 2 h across both the cycles. However, the drug levels measured at 3 h were found to be significantly different across the DPYD*9A genotypes. Individuals with GG genotype showed significantly higher 5-FU levels when compared to AA genotype.

CONCLUSIONS

DPYD*9A polymorphism had a significant influence on the plasma levels of 5-FU after capecitabine administration. The 5-FU levels measured at 3 h corresponding to elimination t_1/2 was significantly higher in patients with GG genotype compared AA genotype.

Evaluation of ABC gene polymorphisms on the pharmacokinetics and pharmacodynamics of capecitabine in colorectal patients: Implications for dosing recommendations

AIMS

The aims are to develop a population pharmacokinetic model of capecitabine (CAP) and its main metabolites after the oral administration of CAP in colorectal cancer patients with different polymorphisms of the ATP-binding cassette (ABC) gene and a population pharmacokinetic/pharmacodynamic model capable of accounting for the neutropenic effects, and to optimize the dosing strategy based on the polymorphisms of the ABC gene and/or the administration regimen as a single agent or in combination.

METHODS

Forty-eight patients diagnosed with colorectal cancer were included, with 432 plasma levels of CAP, 5'-desoxi-5-fluorouridine (5'-DFUR) and 5-fluorouracil (5-FU), and 370 neutrophil observations. Capecitabine doses ranged from 1250 to 2500 mg/m² /24 h. Plasma measurements of CAP, 5'-DFUR and 5-FU were obtained at 1, 2 and 3 hours post administration. Neutrophil levels were measured between day 15 and day 24 post administration.

RESULTS

The pharmacokinetic model incorporates oxaliplatin as a covariate on absorption lag time, rs6720173 (ABCG5 gene) on clearance of 5'-DFUR (182% increase for mutated rs6720173) and rs2271862 (ABCA2 gene) on clearance of 5-FU (184% increase for mutated rs2271862). System- (Circ₀ = 3.54 × 10⁹ cells/mL, MTT = 204 hours and γ = 6.0 × 10^-2 ) and drug-related (slope [SLP] = 3.1 × 10^-2 mL/mg). Co-administration of oxaliplatin resulted in a 2.84-fold increase in SLP. The predicted exposure thresholds to G3/4 neutropenia in combination and monotherapy were 26 and 70 mg·h/L, respectively.

CONCLUSIONS

The population pharmacokinetic/pharmacodynamic model characterized the time course of capecitabine and its metabolites in plasma. Dose recommendations of capecitabine in patients with mutated and wild allele for single nucleotide polymorphisms rs2271862 of ≤3000 and ≤2400 mg/m² /24 h in monotherapy and ≤1750 and ≤600 mg/m² /24 h in combination with oxaliplatin, respectively, have been proposed.

Silver nanoparticles-tragacanth gel as a green membrane for effective extraction and determination of capecitabine

A novel eco-friendly and effective electromembrane extraction method combining high-performance liquid chromatography with UV detection was developed for the enrichment and determination of capecitabine. Tragacanth-silver nanoparticles conjugated gel was prepared by dissolving the tragacanth powder in synthesized silver nanoparticles solution and was used as a green membrane in electromembrane extraction. The porosity and presence of silver nanoparticles in the gel were characterized by field emission scanning electron microscopy. This new electromembrane extraction approach uses neither organic solvent nor carrier agents to extract the target analyte. The best electromembrane extraction efficiency was obtained by using 4.0 mm membrane gel thickness containing 2.5% w/v of tragacanth gum, donor phase pH = 5.0, acceptor phase pH = 3.0, applied voltage 50 V, extraction time 20 min, and agitation rate 500 rpm. During method validation under the optimized conditions, good linearity dynamic range between 1 and 500 ng/mL with the coefficient of determination (R² ) = 0.998 was obtained. Limit of detection and Limit of quantitation were estimated to be 0.84 and 1.0 ng/mL, respectively. Finally, the applicability of this method in real samples was confirmed by an acceptable performance in extraction and determination of capecitabine in human plasma samples.

Stopped-flow chemiluminescence determination of the anticancer drug capecitabine: Application in pharmaceutical analysis and drug-delivery systems

Capecitabine is a chemotherapeutic agent used for the treatment of patients with metastatic cancers. This study aimed at determining the drug capecitabine in a simple chemiluminescence (CL) system of acidic potassium permanganate using the stopped-flow injection technique. Statistical methods were used to detect optimum conditions. The method showed two linear calibration ranges from 6.7 × 10^-6 to 6.7 × 10^-5 mol L^-1 and from 6.7 × 10^-5 to 2.7 × 10^-3 mol L^-1 with a detection limit of 1.5 × 10^-6 mol L^-1 . Chitosan-modified magnetic nanoparticles were studied in the drug-delivery experiments. According to the pH sensitivity of chitosan and low pH values in tumour cells, the chitosan-coated magnetic nanoparticles could provide a good targeting drug-delivery system to tumour sites. To evaluate the applicability of the method, the capecitabine-loaded magnetic chitosan nanoparticles were synthesized with two different cross-linkers; loading and releasing rates of the drug were investigated using the proposed CL method and an ultraviolet-visible light spectrophotometric method (absorption at 305 nm). The results showed a good correlation between the two methods, and it was found that the synthesized chitosan-modified magnetic nanoparticles could be used for pH-dependent release of capecitabine in cancer cells. Moreover, determination of capecitabine in tablets and synthetic samples was performed.

A Validated Stability-Indicating HPTLC Method for the Estimation of Capecitabine in its Tablet Dosage Form

Background:

Capecitabine is an orally available prodrug of 5-flurouracil used in the treatment of breast cancer, metastatic colorectal cancer and stage III colorectal cancer. Various studies have reported the HPLC, HPLC-MS, MS/MS methods for estimation of capecitabine. However, till date HPTLC method for estimation of capecitabine and its validation is not reported in tablet dosage form.

Introduction:

Presented study deals with the development and validation of stability indicating high performance thin layer chromatography method for the determination of Capecitabine in tablet dosage form.

Methods:

The method was developed using precoated HPTLC plates with silica gel 60 F254 as stationary phase and toluene-methanol the ratio of 7.5:2.5 v/v as the mobile phase. Capecitabine (RF 0.48 ± 0.03) and its degradation products were well resolved. The wavelength selected for study was 240 nm. The method was linear in the concentration range 50–550 ng/band with a correlation coefficient of 0.994. The repeatability for six samples was 1.25% RSD. The intraday and interday precisions were 1.46-1.71%RSD and 1.31-1.67% RSD, respectively. The accuracy (recovery) was found to be in the range of 99.10-101.23% with LOD and LOQ were found to be 0.650 and 1.765 mg/band. The mean content of drug in tablet dosage form was found to be 101.51% with a % RSD of 1.20. The drug was subjected to stress conditions such as hydrolysis, oxidation, photolysis, and heat.

Results:

Degradation products produced as a result of the stress conditions did not interfere with the detection of Capecitabine; therefore, the proposed technique can be considered stability-indicating. Capecitabine did not degrade under thermal and photolytic conditions but showed degradation under acidic and alkaline conditions with 15 and 11% decompositions respectively.

Conclusion:

The developed method was found to be facile, simple, specific, precise, and stabilityindicating. It can be employed for the routine analysis of capecitabine in tablet dosage form.

Preparation of a ZnO nanoparticles/multiwalled carbon nanotubes/carbon paste electrode as a sensitive tool for capecitabine determination in real samples

The present study describes the fabrication of a sensitive electrochemical sensor for the determination of capecitabine (Cap).

Quantitative determination of capecitabine and its six metabolites in human plasma using liquid chromatography coupled to electrospray tandem mass spectrometry

Capecitabine is the oral prodrug of the anticancer drug 5-fluorouracil (5-FU). The purpose of this study was to quantify capecitabine and its metabolites including 5'-deoxy-5-fluorocytidine (5'-dFCR), 5'-deoxy-5-fluorouridine (5'-dFUR), 5-FU, dihydro-5-fluorouracil (FUH(2)), α-fluoro-ureidopropionic acid (FUPA) and fluoro-β-alanine (FBAL) in human plasma using liquid chromatography coupled to electrospray tandem mass spectrometry. To this end two individual assays were developed: one for the simultaneous quantification of capecitabine, 5'-dFCR and 5'-dFUR using reversed phase chromatography and gradient elution, and one assay for 5-FU, FUH(2), FUPA and FBAL using hydrophilic interaction chromatography and isocratic elution. Both assays were fully validated according to current FDA guidelines. Total run time for the capecitabine assay was 9.0min, and of the 5-FU assay 5.0min. Analyte extraction was performed by protein precipitation. Stable labeled isotopes for each of the analytes were used as internal standards. The linear ranges of the analytes were 50-6000ng/mL for the capecitabine assay and 50-5000ng/mL for the 5-FU assay. Validation results demonstrate that capecitabine and its metabolites can be rapidly, accurately, precisely and robustly quantified in human plasma with the presented methods. Both assays are currently in extensive use in support of pharmacokinetic studies in patients treated with capecitabine or 5-FU.

Phase I pharmacokinetic study of chronomodulated dose-intensified combination of capecitabine and oxaliplatin (XELOX) in metastatic colorectal cancer

PURPOSE

To evaluate the maximum tolerated dose (MTD) and pharmacokinetic profile of a chronomodulated, dose-intensified regimen of capecitabine in combination with oxaliplatin (XELOX) in metastatic colorectal cancer (mCRC).

METHODS

Patients (N = 18) with 0 or 1 line of prior chemotherapy received oxaliplatin 100 mg/m(2) on day 1 from 1400 to 1800 hours with escalating dose levels of capecitabine (2,500, 3,000, 3,500, 4,000, 4,500, and 5,000 mg) once daily taken at 2400 hours on days 1-5. Each cycle lasted 14 days.

RESULTS

The MTD of capecitabine was 4,500 mg. Transaminitis and anemia were the commonest non-hematologic and hematologic toxicities, respectively. Toxicities were generally mild, with only five occurrences of grade 3 toxicity and none of grade 4. There were no dose-limiting toxicities, defined as specific grade 3 or 4 toxicities occurring in the first two cycles of treatment. The objective response rate was 33.3 %, and median overall survival was 16.3 months (95 % CI: 11.2-18.2 months). The maximum plasma concentration (C(max)) and area under plasma concentration-time curve from time 0 to infinity (AUC([0-∞])) of the capecitabine metabolites in our fixed-dosing chronomodulated regimen were comparable to values seen with comparably dose-intense regimens but associated with significantly reduced toxicity.

CONCLUSIONS

Chronomodulated dose-intensified XELOX facilitates delivery of dose-intense treatment in mCRC with a favorable therapeutic index that is promising.

Analysis of anticancer drugs: a review

In the last decades, the number of patients receiving chemotherapy has considerably increased. Given the toxicity of cytotoxic agents to humans (not only for patients but also for healthcare professionals), the development of reliable analytical methods to analyse these compounds became necessary. From the discovery of new substances to patient administration, all pharmaceutical fields are concerned with the analysis of cytotoxic drugs. In this review, the use of methods to analyse cytotoxic agents in various matrices, such as pharmaceutical formulations and biological and environmental samples, is discussed. Thus, an overview of reported analytical methods for the determination of the most commonly used anticancer drugs is given.

A new, validated HPLC-MS/MS method for the simultaneous determination of the anti-cancer agent capecitabine and its metabolites: 5'-deoxy-5-fluorocytidine, 5'-deoxy-5-fluorouridine, 5-fluorouracil and 5-fluorodihydrouracil, in human plasma

A rapid and selective liquid chromatography/tandem mass spectrometric method was developed for the simultaneous determination of capecitabine and its metabolites 5'-deoxy-5-fluorocytidine (5'-DFCR), 5'-deoxy-5-fluorouracil (5'-DFUR), 5-fluorouracil (5-FU) and dihydro-5-fluorouracil (FUH(2)) in human plasma. A 200 microL human plasma aliquot was spiked with a mixture of internal standards fludarabine and 5-chlorouracil. A single-step protein precipitation method was employed using 10% (v/v) trichloroacetic acid in water to separate analytes from bio-matrices. Volumes of 20 microL of the supernatant were directly injected onto the HPLC system. Separation was achieved on a 30 x 2.1 mm Hypercarb (porous graphitic carbon) column using a gradient by mixing 10 mm ammonium acetate and acetonitrile-2-propanol-tetrahydrofuran (1 : 3 : 2.25, v/v/v). The detection was performed using a Finnigan TSQ Quantum Ultra equipped with the electrospray ion source operated in positive and negative mode. The assay quantifies a range from 10 to 1000 ng/mL for capecitabine, from 10 to 5000 ng/mL for 5'-DFCR and 5'-DFUR, and from 50 to 5000 ng/mL for 5-FU and FUH(2) using a plasma sample of 200 microL. Correlation coefficients (r(2)) of the calibration curves in human plasma were better than 0.99 for all compounds. At all concentration levels, deviations of measured concentrations from nominal concentration were between -4.41 and 3.65% with CV values less than 12.0% for capecitabine, between -7.00 and 6.59% with CV values less than 13.0 for 5'-DFUR, between -3.25 and 4.11% with CV values less than 9.34% for 5'-DFCR, between -5.54 and 5.91% with CV values less than 9.69% for 5-FU and between -4.26 and 6.86% with CV values less than 14.9% for FUH(2). The described method was successfully applied for the evaluation of the pharmacokinetic profile of capecitabine and its metabolites in plasma of treated cancer patients.

Phase I trial of oxaliplatin, infusional 5-fluorouracil, and leucovorin (FOLFOX4) with erlotinib and bevacizumab in colorectal cancer

RATIONALE

This phase I study was conducted to determine the maximum tolerated dose (MTD) of erlotinib, an oral epidermal growth factor receptor tyrosine kinase inhibitor, with 5-fluorouracil/leucovorin/oxaliplatin (FOLFOX4) in patients with advanced colorectal cancer (CRC). Bevacizumab was later included as standard of care at the MTD.

PATIENTS AND METHODS

Patients received FOLFOX4 with escalating doses of erlotinib: dose level (DL) 1, 50 mg; DL 2, 100 mg; and DL 3, 150 mg once daily continuously. Bevacizumab 5 mg/kg days 1 and 15 was added at the MTD upon Food and Drug Administration approval. Correlative studies included pharmacokinetics, pharmacodynamics was assessed in paired skin biopsies, and fluorodeoxyglucose positron emission tomography scans.

RESULTS

Fifteen patients received 60 cycles (120 FOLFOX treatments). Two dose-limiting toxicities (DLTs) were seen at DL 3: intolerable grade 2 rash (Common Terminology Criteria for Adverse Events version 2) lasting > 1 week, and grade 4 neutropenia. Dose level 2 was expanded to 6 more patients, this time adding bevacizumab, and 1 DLT of grade 3 mucositis occurred. As expected, the primary toxicities were cytopenias, diarrhea, rash, and fatigue. There were 2 occurrences of pneumatosis. One patient experienced an unrelated grade 4 myocardial infarction before starting chemotherapy. No pharmacokinetic drug interactions were observed. The Response Evaluation Criteria in Solid Tumors response rate was 11 of 14 (78%), median progression-free survival was 9.5 months, and median overall survival was 30 months. Three patients are currently alive > 3 years, with 1 having no evidence of disease.

CONCLUSION

The MTD of erlotinib with FOLFOX4 with or without bevacizumab is 100 mg daily. The regimen appeared to increase toxicity but showed activity in patients with CRC.

Phase IB study of the mTOR inhibitor ridaforolimus with capecitabine

PURPOSE

Synergistic/additive cytotoxicity in tumor models and widespread applicability of fluoropyrimidines in solid tumors prompted the study of the combination of the mammalian target of rapamycin (mTOR) inhibitor, non-prodrug rapamycin analog ridaforolimus, with capecitabine.

PATIENTS AND METHODS

Thirty-two adult patients were treated. Intravenous ridaforolimus was given once weekly for 3 weeks and capecitabine was given from days 1 to 14 every 4 weeks. Ridaforolimus was given at 25, 37.5, 50, or 75 mg with capecitabine at 1,650 mg/m(2) or 1,800 mg/m(2) divided into two daily doses. Pharmacokinetics of both drugs were determined during cycles 1 and 2. Pharmacodynamic studies in peripheral blood mononuclear cells (PBMCs) and wound tissue of the skin characterized pathways associated with the metabolism or disposition of fluoropyrimidines and mTOR and ERK signaling.

RESULTS

Two recommended doses (RDs) were defined: 75 mg ridaforolimus/1,650 mg/m(2) capecitabine and 50 mg ridaforolimus/1,800 mg/m(2) capecitabine. Dose-limiting toxicities were stomatitis and skin rash. One patient achieved a partial response lasting 10 months and 10 of 29 evaluable patients had stable disease for ≥ 6 months. The only pharmacokinetic interaction was a ridaforolimus-induced increase in plasma exposure to fluorouracil. PBMC data suggested that prolonged exposure to capecitabine reduced the ridaforolimus inhibition of mTOR. Ridaforolimus influenced the metabolism of fluoropyrimidines and inhibited dihydropyrimidine dehydrogenase, behavior similar to that of rapamycin. Inhibition of the target thymidylate synthase by capecitabine was unaffected. mTOR and ERK signaling was inhibited in proliferating endothelial cells and was more pronounced at the RD with the larger amount of ridaforolimus.

CONCLUSION

Good tolerability, feasibility of prolonged treatment, antitumor activity, and favorable pharmacologic profile support further investigation of this combination.

Rapid and simultaneous determination of capecitabine and its metabolites in mouse plasma, mouse serum, and in rabbit bile by high-performance liquid chromatography

A rapid high-performance liquid chromatography method has been developed for simultaneous determination of capecitabine and its metabolites: 5'-deoxy-5-fluorocytidine (5'-DFCR), 5'-deoxy-5-fluorouridine (5'-DFUR) and 5-fluorouracil (5-FU). 5'-DFCR was synthesized by hydrolyzing capecitabine using commercially available carboxyl esterase (CES) and characterized by NMR, mass spectrometry and elemental analysis. Base-line separations between capecitabine, 5'-DFCR, 5'-DFUR and 5-FU were found with symmetrical peak shapes on a Discovery RP-amide C16 column using 10 mM ammonium acetate at pH 4.0 and methanol as the mobile phase. The retention times of capecitabine, 5'-DFCR, 5'-DFUR and 5-FU were 8.9, 5.0, 5.3 and 3.0 min, respectively. Linear calibration curves were obtained for each compound across a range from 1 to 500 microg ml(-1). The intra- and inter-day relative standard deviations (%RSD) were <5%. A single-step protein precipitation method was employed for separation of the analytes from bio-matrices. Greater than 85% recoveries were obtained for capecitabine, 5'-DFCR, 5'-DFUR and 5-FU from bio-fluids including mouse plasma, mouse serum and rabbit bile.

Pesticide poisoning in domestic animals and livestock in Austria: a 6 years retrospective study

A 6 years retrospective study of pesticide poisonings in domestic animals and livestock from 1999 to 2004 submitted to the Institute for Medical Chemistry, University of Veterinary Medicine, Vienna in Austria was compiled and analysed. Totally 380 pesticide analysis requests were referred by veterinary practitioners, from the Institute for Pathology of the above university, by regional and central governments as well as local police departments and district administrations, animal protectionist groups, public health authorities and private clients. Among the total number of suspected samples for pesticides, 175 (46.1%) cases were found positive to contain pesticides of various kinds. Among the pesticides found, carbamate insecticides were most prominent, representing 50.3% of the total positive cases. These compounds were followed by rodenticides-anticoagulants with 18.9% of the positive results, by organophosphate insecticides 5.1%, and by the rodenticides-nonanticoagulant 3.4%, the other 22.3% included molluscicides, herbicides, etc. In totally 225 animals, 123 animals were found positive for pesticide intoxication, among them 47.2% were dogs, 34.1% were cats 9.8% of other species and 8.9% of unspecified animal samples. The pesticides were characterized by HPLC-techniques using commercially available standards. The aim of this Austrian survey was to determine the incidence and frequency of confirmed pesticide intoxications in animals in Austria and to emphasize its relevance in veterinary practice for livestock and domestic animals.