High-performance liquid chromatographic method for simultaneous determination of [1-methyl-14C]caffeine and its eight major metabolites in rat urine

Schrader, Eberhard; Klaunick, Götz; Jorritsma, Ute; Neurath, Hartmud; Hirsch‐Ernst, Karen Ildico; Kahl, Georg F.; Foth, Heidi

doi:10.1016/s0378-4347(99)00040-7

Cited by 12 publications

(4 citation statements)

References 21 publications

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“…OP1 has been also reported as a product of the reaction of CAF with ozone . OP4, a biological metabolite of CAF, has been identified as a product of the degradation of CAF by activated oxone, ozone, electrochemical oxidation, and activated peroxymonosulfate …”

Section: Resultsmentioning

confidence: 99%

Oxidation of caffeine by acid‐activated ferrate(VI): Effect of ions and natural organic matter

et al. 2017

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Caffeine (CAF) is the most commonly consumed stimulant and frequently detected emerging pollutant in influents and effluents of wastewater treatment plants (WWTP) and surface waters. Acid‐activated ferrate(VI) (FeVI O42−, Fe(VI)) oxidizes CAF in water in seconds to minutes at three times lower molar ratio of Fe(VI) to CAF than oxidative transformation observed in hours by nonactivated Fe(VI) (8.0 vs. 25.0). CAF oxidation by acid‐activated Fe(VI) is not affected by ionic constituents of water. Organic components of natural organic matter (NOM) and secondary effluent wastewater (SE) decrease efficiency of CAF transformation. However, acid‐activated Fe(VI) could mineralize other organics present in both NOM and SE as indicated by the dissolved organic carbon (DOC) removal. Comparatively, no mineralization was seen without activation of Fe(VI). Four oxidized products of CAF were identified by a liquid chromatography high resolution mass spectrometry technique. The reaction pathways of the oxidation of CAF by activated Fe(VI) have been proposed. © 2017 American Institute of Chemical Engineers AIChE J, 2017

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Section: Resultsmentioning

confidence: 99%

Oxidation of caffeine by acid‐activated ferrate(VI): Effect of ions and natural organic matter

et al. 2017

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“…It is interesting to note that in conjunction with the above study, a selective and sensitive reverse-phase liquid chromatographic method was developed by Schrader et al ( 1999 ) for the simultaneous analysis of [1-methyl-14C] caffeine and its eight major radiolabel-led metabolites in rat urine. Separation of the complex mixture of metabolites was achieved by gradient elution with a dual solvent system using an endcapped C18 reverse-phase column, which, in contrast to commonly used C18 reverse-phase columns, also allows the separation of the two isomers of 6-amino-5-( N -formylmethylamino)-1,3-dimethyluracil (1,3,7-DAU), a metabolite of quantitative importance predominantly occurring in rats.…”

Section: Pharmacokineticsmentioning

confidence: 99%

Evaluation of the reproductive and developmental risks of caffeine

Brent

Christian

Diener

2011

Birth Defects Research Pt B

120

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A risk analysis of in utero caffeine exposure is presented utilizing epidemiological studies and animal studies dealing with congenital malformation, pregnancy loss, and weight reduction. These effects are of interest to teratologists, because animal studies are useful in their evaluation. Many of the epidemiology studies did not evaluate the impact of the “pregnancy signal,” which identifies healthy pregnancies and permits investigators to identify subjects with low pregnancy risks. The spontaneous abortion epidemiology studies were inconsistent and the majority did not consider the confounding introduced by not considering the pregnancy signal. The animal studies do not support the concept that caffeine is an abortafacient for the wide range of human caffeine exposures. Almost all the congenital malformation epidemiology studies were negative. Animal pharmacokinetic studies indicate that the teratogenic plasma level of caffeine has to reach or exceed 60 µg/ml, which is not attainable from ingesting large amounts of caffeine in foods and beverages. No epidemiological study described the “caffeine teratogenic syndrome.” Six of the 17 recent epidemiology studies dealing with the risk of caffeine and fetal weight reduction were negative. Seven of the positive studies had growth reductions that were clinically insignificant and none of the studies cited the animal literature. Analysis of caffeine's reproductive toxicity considers reproducibility and plausibility of clinical, epidemiological, and animal data. Moderate or even high amounts of beverages and foods containing caffeine do not increase the risks of congenital malformations, miscarriage or growth retardation. Pharmacokinetic studies markedly improve the ability to perform the risk analyses. Birth Defects Res (Part B) 92:152–187, 2011. © 2011 Wiley-Liss, Inc.

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“…Besides they are components of over-thecounter drug mixtures for pain, cold, and cough [3]. The analysis of these compounds in body fluids is important not only for monitoring of asthma, neonatal apnoea, or bronchial spasm, but also for non-invasive assessment of various isoforms of cytochrome P450 (CYP) activity [4,5] or in doping analysis [6,7].…”

Section: Introductionmentioning

confidence: 99%

Separation, pre‐concentration, and HPLC analysis of methylxanthines in urine samples

Zydroń

Baranowski

Baranowska³

2004

J of Separation Science

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An SPE method, using RP18 phases, for the simultaneous extraction of caffeine, theobromine, theophylline, paraxanthine, 1-methylxanthine, 3-methylxanthine, 7-methylxanthine, 1-methyluric acid, 1,3-dimethyluric acid, 1,7-dimethyluric acid, and 1,3,7-trimethyluric acid from urine has been developed. Besides a gradient HPLC system for the analysis of the compounds of interest on a LiChrosorb RP-18 (7 microm) column with mobile phase containing 0.05% aq. solution of trifluoroacetic acid and acetonitrile has been elaborated. The procedure has been successfully applied to the analysis of methylxanthines and methyluric acids in urine of patients with chronic asthma treated with theophylline and in urine of healthy subjects.

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High-performance liquid chromatographic method for simultaneous determination of [1-methyl-14C]caffeine and its eight major metabolites in rat urine

Cited by 12 publications

References 21 publications

Oxidation of caffeine by acid‐activated ferrate(VI): Effect of ions and natural organic matter

Oxidation of caffeine by acid‐activated ferrate(VI): Effect of ions and natural organic matter

Evaluation of the reproductive and developmental risks of caffeine

Separation, pre‐concentration, and HPLC analysis of methylxanthines in urine samples

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