Urine Extracts (urine + extract)

Distribution by Scientific Domains

Selected Abstracts

Characterization of urinary metabolites of testosterone, methyltestosterone, mibolerone and boldenone in greyhound dogs

T. M. Williams
Androgenic steroids are used in female greyhound dogs to prevent the onset of estrus; moreover, these steroids also have potent anabolic activity. As anabolic steroids increase muscle mass and aggression in animals, the excessive use of these agents in racing greyhounds gives an unfair performance advantage to treated dogs. The biotransformation of most anabolic steroids has not been determined in greyhound dogs. The objective of the present study was to identify the urinary metabolites of testosterone, methyltestosterone, mibolerone, and boldenone in greyhound dogs. These steroids were administered orally (1 mg/kg) to either male or female greyhound dogs and urine samples were collected pre-administration and at 2, 4, 8, 12, 24, 72, and 96 h post-administration. Urine extracts were analyzed by high-performance liquid chromatography/mass spectrometry (HPLC/MS) to identify major metabolites and to determine their urinary excretion profiles. Major urinary metabolites, primarily glucuronide, conjugated and free, were detected for the selected steroids. Sulfate conjugation did not appear to be a major pathway for steroid metabolism and excretion in the greyhound dog. Phase I biotransformation was also evaluated using greyhound dog liver microsomes from untreated dogs. The identification of several in vivo steroid metabolites generated in this study will be useful in detecting these steroids in urine samples submitted for drug screening. [source]

Determination of bupivacaine and metabolites in rat urine using capillary electrophoresis with mass spectrometric detection

Ryan M. Krisko
Abstract A method using capillary electrophoresis-mass spectrometry (CE-MS) was developed for the structural elucidation of bupivacaine and metabolites in rat urine. Prior to CE-MS analysis, solid-phase extraction (SPE) was used for sample cleanup and preconcentration purposes. Exact mass and tandem mass spectrometric (MS/MS) experiments were performed to obtain structural information about the unknown metabolites. Two instruments with different mass analyzers were used for mass spectrometric detection. A quadrupole time-of-flight (Q-TOF) and a magnetic sector hybrid instrument were coupled to CE and used for the analysis of urine extracts. Hydroxybupivacaine as well as five other isomerically different metabolites were detected including methoxylated bupivacaine. [source]

Studies on the metabolism of the ,9-tetrahydrocannabinol precursor ,9-tetrahydrocannabinolic acid A (,9-THCA-A) in rat using LC-MS/MS, LC-QTOF MS and GC-MS techniques

Julia Jung
Abstract In Cannabis sativa, ,9-Tetrahydrocannabinolic acid-A (,9-THCA-A) is the non-psychoactive precursor of ,9-tetrahydrocannabinol (,9-THC). In fresh plant material, about 90% of the total ,9-THC is available as ,9-THCA-A. When heated (smoked or baked), ,9-THCA-A is only partially converted to ,9-THC and therefore, ,9-THCA-A can be detected in serum and urine of cannabis consumers. The aim of the presented study was to identify the metabolites of ,9-THCA-A and to examine particularly whether oral intake of ,9-THCA-A leads to in vivo formation of ,9-THC in a rat model. After oral application of pure ,9-THCA-A to rats (15 mg/kg body mass), urine samples were collected and metabolites were isolated and identified by liquid chromatography-mass spectrometry (LC-MS), liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high resolution LC-MS using time of flight-mass spectrometry (TOF-MS) for accurate mass measurement. For detection of ,9-THC and its metabolites, urine extracts were analyzed by gas chromatography-mass spectrometry (GC-MS). The identified metabolites show that ,9-THCA-A undergoes a hydroxylation in position 11 to 11-hydroxy-,9-tetrahydrocannabinolic acid-A (11-OH-,9-THCA-A), which is further oxidized via the intermediate aldehyde 11-oxo-,9-THCA-A to 11-nor-9-carboxy-,9-tetrahydrocannabinolic acid-A (,9-THCA-A-COOH). Glucuronides of the parent compound and both main metabolites were identified in the rat urine as well. Furthermore, ,9-THCA-A undergoes hydroxylation in position 8 to 8-alpha- and 8-beta-hydroxy-,9-tetrahydrocannabinolic acid-A, respectively, (8,-Hydroxy-,9-THCA-A and 8,-Hydroxy-,9-THCA-A, respectively) followed by dehydration. Both monohydroxylated metabolites were further oxidized to their bishydroxylated forms. Several glucuronidation conjugates of these metabolites were identified. In vivo conversion of ,9-THCA-A to ,9-THC was not observed. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Isotopic pattern and accurate mass determination in urine drug screening by liquid chromatography/time-of-flight mass spectrometry

Suvi Ojanperš
An efficient method was developed for toxicological drug screening in urine by liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry. The method relies on a large target database of exact monoisotopic masses representing the elemental formulae of reference drugs and their metabolites. Mass spectral identification is based on matching measured accurate mass and isotopic pattern (SigmaFit‘) of a sample component with those in the database. Data post-processing software was developed for automated reporting of findings in an easily interpretable form. The mean and median of SigmaFit‘ for true-positive findings were 0.0066 and 0.0051, respectively. The mean and median of mass error absolute values for true-positive findings were 2.51 and 2.17,ppm, respectively, corresponding to 0.65 and 0.60,mTh. For routine screening practice, a SigmaFit‘ tolerance of 0.03 and a mass tolerance of 10,ppm were chosen. Ion abundance differences from urine extracts did not affect the accuracy of the automatically acquired SigmaFit‘ or mass values. The results show that isotopic pattern matching by SigmaFit‘ is a powerful means of identification in addition to accurate mass measurement. Copyright © 2006 John Wiley & Sons, Ltd. [source]