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F T Delbeke

Publications and source records attributed to F T Delbeke.

At least 55 records · Page 3Linked to original sources
PubMed1991

Urinary excretion of theobromine in horses given contaminated pelleted food.

A high pressure liquid chromatographic (HPLC) method for measuring the theobromine content in cocoa husks, pelleted food and horse urine is described. Starting with 2 ml of urine, concentrations of 500 ng/ml could easily be detected. When feed containing 38.4 mg of theobromine was given twice daily to horses for 2 1/2 days, two days were needed after the last intake before the theobromine concentrations fell below the threshold value of 2 micrograms/ml. The time at which the peak excretion rate occurred varied from 2 to 12 h after the last administration, while the excretion rate seemed to be dependent on the urinary flow. Theobromine could not be detected in plasma after administration in this way.

Animal Feed↗
PubMed1991

Urinary concentrations of codeine and morphine after the administration of different codeine preparations in relation to doping analysis.

A capillary GC method with nitrogen-specific detection is described for the analysis of codeine and morphine in urine. Both drugs were determined after enzymatic hydrolysis of the urine. Morphine was derivatized with trifluoroacetic anhydride. For 5-ml samples of urine, the lower detection limits for accurate quantitation were 50 ng ml-1 and 100 ng ml-1 for morphine and codeine, respectively. Both codeine and morphine were already detectable in urine 1 h after the intake of the analgesic preparation Perdolan. Codeine excretion and concentration peaked 2 h after administration of a dose. The percentage of the dose excreted as codeine was 3.0-6.2%. Administration of the antitussive preparation Bisolvon Griblettes resulted in detectable codeine and morphine levels for at least one day; 5.6-9% was excreted as total codeine over 24 h, the conjugated metabolite morphine accounting for 1.7-7.4% of the dose. Nearly the same amounts of codeine and morphine were excreted after administration of the antitussive syrup Bronchodine. The maximum excretion rate of codeine occurred after 1 h. Generally codeine and morphine remained detectable for 12 h. The results of these administration studies are discussed in relation to the codeine and morphine threshold levels recently introduced by the International Cyclist Union.

Chromatography, Gas↗
PubMed1991

The influence of diuretics on the excretion and metabolism of doping agents--V. Dimefline.

A sensitive method for the quantitative determination of the respiratory stimulant dimefline in 5 ml urine using capillary gas chromatography with nitrogen specific detection is presented. After the oral administration of a therapeutical amount of 16 mg dimefline to five subjects only 0.26 +/- 0.16% of the dose is excreted as the conjugated drug in 24 h. The maximum excretion rate occurred 3 h after dosing, the peak concentration being 154 +/- 60 ng ml-1. The influence of diuretics taken 2 h after the administration of dimefline was studied in three subjects. From these results it appeared that the use of acetazolamide and hydrochlorthiazide in order to circumvent a positive dimefline doping case is questionable. Due to the potent diuretic effect of furosemide, the intake of this diuretic could result in a suppression of the dimefline concentration below the detection limit of 10 ng ml-1.

Acetazolamide↗
PubMed1991

Disposition of human drug preparations in the horse. I. Rectally administered indomethacin.

A high-performance liquid chromatographic method to measure urinary indomethacin levels is described. In 0.5 ml urine, 1 micrograms/ml of indomethacin could be detected. Alkaline hydrolysis of urine resulted in the decomposition of indomethacin. When two suppositories of Indocid corresponding to 200 mg indomethacin were administered rectally to four horses the drug was rapidly absorbed and remained detectable in urine from 1 to 12 h. The excretion rate peaked after 2-3 h while the maximal concentration ranged from 18.5 to 80.6 micrograms/ml. Only 8 to 16% of the indomethacin dose was eliminated in urine after 12 h. A fraction of the dose was excreted as the glucuronide conjugate.

Administration, Rectal↗
PubMed1989

ELISA detection of fentanyl in horse urine and plasma.

The prototype of a commercial ELISA test kit designed for fentanyl determination in human urine has been evaluated for screening fentanyl in horse urine and plasma. The measurement of fentanyl after intravenous (2 mg) and intramuscular (0.25 mg) administration in undiluted plasma was not reproducible while accurate quantification of fentanyl in urine greatly depends on the composition of the horse urine. The ELISA assay, however, is simple and could be successfully used for quantitative measurements in diluted urine and for rapid qualitative screening for fentanyl in large numbers of urine samples.

Animals↗
PubMed1988

Comparative study of extraction methods for the GC and GC-MS screening of urine for beta-blocker abuse.

Comparison is made between conventional liquid-liquid extraction and solid-phase extraction techniques using Extrelut-1, Extrelut-3 and C18-RP cartridges respectively for the screening of several beta-blockers in urine. Generally, using GC with nitrogen specific detection as the screening technique, liquid-liquid extraction and Extrelut-1 solid-phase extraction seem to be the methods of choice. However, when the screening and confirmation are performed by GC-MS, solid phase extractions with C18 or Extrelut-1 are valuable alternatives to conventional extraction. Using the different extraction techniques, detection limits and time periods during which the drugs are detectable in urine after oral administration of subtherapeutic amounts of several beta-blockers are determined.

Journal Article↗
PubMed1986

Pharmacokinetics and diuretic effect of bumetanide following intravenous and intramuscular administration to horses.

Concentrations of the potent diuretic bumetanide were determined by a sensitive high performance liquid chromatographic procedure in plasma and urine from horses following intravenous and intramuscular administration of a dose rate of 15 micrograms/kg. The elimination half-life was found to be 6.3 min, the volume of distribution at steady state 68 ml/kg and the total plasma clearance 10.9 ml/min/kg. The onset of diuresis occurred within 15 min and diuresis was no longer apparent 1 h after i.v. administration. Given by the intramuscular (i.m.) route, bumetanide was rapidly absorbed; bioavailability was 70-80%. i.m. administration of bumetanide prolonged its plasma half-life (11-27 min) and enhanced and prolonged its diuretic effect.

Animals↗
PubMed1986

The influence of diuretics on the excretion and metabolism of doping agents. III. Etilamfetamine.

The urinary excretion of etilamfetamine (ethylamphetamine) and its major metabolite amphetamine in humans was followed over a period of several days after the oral administration of two formulations. The excretion of both substances was affected by urinary pH. Excretion peaks were observed 3-4 h after the ingestion of etilamfetamine in a capsule and the proportion of etilamfetamine excreted during 72 h was 22.2 to 54.4%. Excepting a shift in the peak excretion time to 4-5 h, no meaningful pharmacokinetic differences were found when Apetinil-Depot, a retard formulation, was administered. The intake of acetozolamide shortly after etilamfetamine resulted in a decrease of the etilamfetamine excretion during one day and a suppression below the detection limit for periods varying from 2-7 h post-dosing. Although the etilamfetamine excretion was suppressed from 2 to at least 10 h post-dosing, the action of the diuretic clofenamide on the etilamfetamine excretion is generally not so obvious as that of acetazolamide. The administration of furosemide only reduced the etilamfetamine concentrations by a factor of 4 to 5 during a 2-h period.

Acetazolamide↗
PubMed1986

The influence of diuretics on the excretion and metabolism of doping agents. II. Phentermine.

The urinary excretion of phentermine in humans was followed over a period of several days after the oral administration of two formulations. The intake of phentermine in a capsule generally resulted in an excretion peak 4 h after the administration followed by a second peak 12 or 24 h post dosing. The total amount excreted during 72 h varied from 62.7 to 84.8%. Concerning the administration of Ionamine 15, a sustained release formulation, the maximal excretion rate was spread over 3-9 h, while more than 85% of phentermine were excreted after 72 h. The excretion was affected by urinary pH. The intake of acetazolamide shortly after phentermine resulted in a decrease of the phentermine excretion during one day and in one subject in a suppression below the detection limit 4 h post dosing. The administration of furosemide or bumetanide produced only a diluting effect during 2 h.

Acetazolamide↗
PubMed1985

The influence of diuretics on the excretion and metabolism of doping agents - I. Mephentermine.

The urinary excretion of mephentermine and its major metabolite phentermine in human volunteers was followed over a period of several days after oral administration of mephentermine. The excretion of both substances was affected by urinary pH. Maximum excretion was observed 2-4 h after administration and the total proportion of mephentermine excreted during 54 h was 57 to 83%. Based on urinary values, the biological half-life of elimination of mephentermine was 9.9 +/- 2.6 h. The ingestion of acetazolamide shortly after administration of mephentermine resulted in a decrease in excretion of both mephentermine and phentermine during one day; in some instances, the amounts of these substances in the urine were below the detection limit for a period of 3-9 h. The administration of frusemide only produced a urinary diluting effect during 2-4 h after administration.

Journal Article↗
PubMed1984

Caffeine: use and abuse in sports.

The urinary caffeine content was compared between a control group and 775 cyclists checked for doping during the 1982 season. The data for sportsmen demonstrate that the (mis)use of caffeine is more pronounced in both professional and amateur classes than in the younger categories (debutant and junior). Caffeine was also monitored during a 60-h period in the urine of several coffee drinkers. Based on all results, a "maximum level of caffeine" of 15 micrograms X ml-1 in urine for sporting competitions is proposed.

Adolescent↗
PubMed1983

Pentafluorobenzoyl derivatives of doping agents. I. Extractive benzoylation and gas chromatography with electron-capture detection of primary and secondary amines.

A sensitive and rapid method for the gas chromatographic (with electron-capture detection) confirmation of derivable sympathomimetic amines is described. Extractive derivatization with pentafluorobenzoyl chloride is performed on 2-ml urine or plasma samples. Especially for primary amines, the method appears to be very sensitive. Mass spectral data allowed confirmation of the monobenzoylation of all congeners.

Benzoates↗