Carnitine and γ‐Butyrobetaine Stimulate Elimination of Meldonium due to Competition for OCTN2‐mediated Transport

Meldonium (3‐(2,2,2‐trimethylhydrazinium)propionate) is the most potent clinically used inhibitor of organic cation transporter 2 (OCTN2). Inhibition of OCTN2 leads to a decrease in carnitine and acylcarnitine contents in tissues and energy metabolism optimization‐related cardioprotective effects. The recent inclusion of meldonium in the World Anti‐Doping Agency List of Prohibited Substances and Methods has raised questions about the pharmacokinetics of meldonium and its unusually long elimination time. Therefore, in this study, the rate of meldonium washout after the end of the treatment was tested with and without administration of carnitine, γ‐butyrobetaine (GBB) and furosemide to evaluate the importance of competition for OCTN2 transport in mice. Here, we show that carnitine and GBB administration during the washout period effectively stimulated the elimination of meldonium. GBB induced a more pronounced effect on meldonium elimination than carnitine due to the higher affinity of GBB for OCTN2. The diuretic effect of furosemide did not significantly affect the elimination of meldonium, carnitine and GBB. In conclusion, the competition of meldonium, carnitine and GBB for OCTN2‐mediated transport determines the pharmacokinetic properties of meldonium. Thus, due to their affinity for OCTN2, GBB and carnitine but not furosemide stimulated meldonium elimination. During long‐term treatment, OCTN2‐mediated transport ensures a high muscle content of meldonium, while tissue clearance depends on relatively slow diffusion, thus resulting in the unusually long complete elimination period of meldonium.     

Meldonium residues in milk: A possible scenario for inadvertent doping in sports?

Lately, the veterinary drug Emidonol® has been discussed as a possible scenario for inadvertent doping in sports. Emidonol® is approved for use in livestock breeding, exhibiting antihypoxic and weak sedative effects. The veterinary drug rapidly dissociates into meldonium, a substance prohibited in sports, and is excreted largely in its unchanged form into urine. To investigate if residues of meldonium in edible produce may result in adverse analytical findings in sports drug testing, a pilot study was conducted with three volunteers consuming a single dose of 100 ml meldonium-spiked milk at a concentration of 500 ng/ml (Study 1), and multiple doses of 100 ml of meldonium-spiked milk (500 ng/ml) on five consecutive days (Study 2). In the single dose study, urinary meldonium concentrations peaked between 2 and 6 h post-administration with maximum values of 7.5 ng/ml, whereas maximum meldonium concentrations of 18.6 ng/ml were determined after multiple doses 4 h post-administration. All samples were analyzed using an established and validated protocol based on HILIC-HRMS/MS.     

Elimination profile of triamcinolone in urine following oral administration

Triamcinolone (T) is a glucocorticoid commonly used to relieve inflammation and treat arthritis, severe allergies, and asthma; however, it is banned by the World Anti‐Doping Agency in competition for athletes when administered orally, intravenously, intramuscularly, or rectally. The minimum required performance limit (MRPL) for urinary T is 30 ng/mL. However, the data about the urinary excretion of T after oral administration is limited. We investigate the elimination profile and determine whether single‐dose administration of T would cause a positive doping result. Twelve healthy volunteers received a single‐dose of 4‐mg T rally, and urine samples were collected for 24 hours. A validated liquid chromatography–tandem mass spectrometry method was used to determine urinary T levels. Non‐compartmental modeling was used to estimate the pharmacokinetic parameters. All the urinary T concentrations were much higher than the MRPL. The peak urinary T concentration was 3211.4 ± 860.3 ng/mL (mean ± SD), time to peak concentration was 1.7 ± 0.9 hours, and the estimated elimination half‐life was 4.4 ± 2.8 hours. About 27.76% of the consumed dose was eliminated via urine within 24 hours of intake. After a single‐dose oral administration, urinary T concentrations still exceeded the MRPL after 24 hours. This information could be useful for limiting the misuse of T. Athletes should be aware when using T in competition and acquire approval for a therapeutic use exemption prior to use. Moreover, the elimination profile of orally administered T may be crucial information for distinguishing different dosage routes.     

Detection and pharmacokinetics of grapiprant following oral administration to exercised Thoroughbred horses

Traditional therapeutic options for the treatment of lameness associated with inflammation in performance horses include administration of cyclooxygenase enzyme inhibiting non‐steroidal anti‐inflammatory drugs (NSAID). As long‐term use of these drugs can adversely impact the health of the horse, anti‐inflammatories with a more favorable safety profile are warranted. Grapiprant is a newly approved non‐cyclooxygenase inhibiting NSAID that has demonstrated efficacy and safety in other species and which may be a valuable alternative to traditional NSAIDs used in the horse. The objectives of the current study were to describe drug concentrations and the pharmacokinetics of grapiprant in exercised Thoroughbred horses and to develop an analytical method that could be used to regulate its use in performance horses. To that end, grapiprant, at a dose of 2 mg/kg was administered orally to 12 exercised Thoroughbred horses. Blood and urine samples were collected prior to and for up to 96 hours post drug administration. Drug concentrations were measured using liquid chromatography–tandem mass spectrometry. Grapiprant remained above the LOQ of the assay (0.005 ng/mL) in serum for 72 hours post administration and urine concentrations were above the LOQ until 96 hours. The C_max, T_max and elimination half‐life were 31.9 ± 13.9 ng/mL, 1.5 ± 0.5 hours and 5.86 ± 2.46 hours, respectively. The drug was well tolerated in all horses at a dose of 2 mg/kg. Results support further study of this compound in horses. Furthermore, development of a highly sensitive analytical method demonstrate that this compound can be adequately regulated in performance horses.     

Sulfate metabolites as alternative markers for the detection of 4‐chlorometandienone misuse in doping control

Sulfate metabolites have been described as long‐term metabolites for some anabolic androgenic steroids (AAS). 4‐chlorometandienone (4Cl‐MTD) is one of the most frequently detected AAS in sports drug testing and it is commonly detected by monitoring metabolites excreted free or conjugated with glucuronic acid. Sulfation reactions of 4Cl‐MTD have not been studied. The aim of this work was to evaluate the sulfate fraction of 4Cl‐MTD metabolism by liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) to establish potential long‐term metabolites valuable for doping control purposes. 4Cl‐MTD was administered to two healthy male volunteers and urine samples were collected up to 8 days after administration. A theoretical selected reaction monitoring (SRM) method working in negative mode was developed. Ion transitions were based on ionization and fragmentation behaviour of sulfate metabolites as well as specific neutral losses (NL of 15 Da and NL of 36 Da) of compounds with related chemical structure. Six sulfate metabolites were detected after the analysis of excretion study samples. Three of the identified metabolites were characterized by liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) and gas chromatography‐tandem mass spectrometry (GC‐MS/MS). Results showed that five out of the six identified sulfate metabolites were detected in urine up to the last collected samples from both excretion studies. Copyright © 2016 John Wiley & Sons, Ltd.     

Determining the authenticity of athlete urine in doping control by DNA analysis

The integrity of urine samples collected from athletes for doping control is essential. The authenticity of samples may be contested, leading to the need for a robust sample identification method. DNA typing using short tandem repeats (STR) can be used for identification purposes, but its application to cellular DNA in urine has so far been limited. Here, a reliable and accurate method is reported for the successful identification of urine samples, using reduced final extraction volumes and the STR multiplex kit, Promega® PowerPlex ESI 17, with capillary electrophoretic characterisation of the alleles. Full DNA profiles were obtained for all samples (n = 20) stored for less than 2 days at 4 °C. The effect of different storage conditions on yield of cellular DNA and probability of obtaining a full profile were also investigated. Storage for 21 days at 4 °C resulted in allelic drop‐out in some samples, but the random match probabilities obtained demonstrate the high power of discrimination achieved through targeting a large number of STRs. The best solution for long‐term storage was centrifugation and removal of supernatant prior to freezing at ‐20 °C. The method is robust enough for incorporation into current anti‐doping protocols, and was successfully applied to 44 athlete samples for anti‐doping testing with 100% concordant typing. Copyright © 2015 John Wiley & Sons, Ltd.     

Discordant genotyping results using DNA isolated from anti‐doping control urine samples

The UGT2B17 gene deletion polymorphism is known to correlate to urinary concentration of testosterone‐glucuronide and hence this genotype exerts a large impact on the testosterone/epitestosterone (T/E) ratio, a biomarker for testosterone doping. The objective of this study was to assess if DNA isolated from athletes’ urine samples (n = 713) obtained in routine doping controls could be targeted for genotyping analysis for future integration in the athlete's passport. A control population (n = 21) including both urine and blood DNA was used for genotyping concordance test. Another aim was to study a large group (n = 596) of authentic elite athletes in respect of urinary steroid profile in relation to genetic variation. First we found that the genotype results when using urine‐derived DNA did not correlate sufficiently with the genotype obtained from whole blood DNA. Secondly we found males with one or two UGT2B17 alleles had higher T/E (mean 1.63 ± 0.93) than females (mean 1.28 ± 1.08), p˂0.001. Unexpectedly, we found that several male del/del athletes in power sports had a T/E ˃1. If men in power sport exert a different urinary steroid profile needs to be further investigated. The other polymorphisms investigated in the CYP17A1, UGT2B7 and UGT2B15 genes did not show any associations with testosterone and epitestosterone concentrations. Our results show that genotyping using urine samples according to our method is not useful in an anti‐doping setting. Instead, it is of importance for the anti‐doping test programs to include baseline values in the ABP to minimize any putative impact of genotype. Copyright © 2016 John Wiley & Sons, Ltd.     

Adverse analytical findings with clenbuterol among U‐17 soccer players attributed to food contamination issues

The illicit use of growth promoters in animal husbandry has frequently been reported in the past. Among the drugs misused to illegally increase the benefit of stock farming, clenbuterol has held a unique position due to the substance's composition, mechanism of action, metabolism, and disposition. Particularly clenbuterol's disposition in animals' edible tissues destined for food production can cause considerable issues on consumption by elite athletes registered in national and international doping control systems as demonstrated in this case‐related study. Triggered by five adverse analytical findings with clenbuterol among the Mexican national soccer team in out‐of‐competition controls in May 2011, the Fédération Internationale de Football Association (FIFA) initiated an inquest into a potential food contamination (and thus sports drug testing) problem in Mexico, the host country of the FIFA U‐17 World Cup 2011. Besides 208 regular doping control samples, which were subjected to highly sensitive mass spectrometric test methods for anabolic agents, 47 meat samples were collected in team hotels during the period of the tournament and forwarded to Institute of Food Safety, RIKILT. In 14 out of 47 meat samples (30%), clenbuterol was detected at concentrations between 0.06 and 11 µg/kg. A total of 109 urine samples out of 208 doping control specimens (52%) yielded clenbuterol findings at concentrations ranging from 1–1556 pg/ml, and only 5 out of 24 teams provided urine samples that did not contain clenbuterol. At least one of these teams was on a strict ‘no‐meat’ diet reportedly due to the known issue of clenbuterol contamination in Mexico. Eventually, owing to the extensive evidence indicating meat contamination as the most plausible reason for the extraordinary high prevalence of clenbuterol findings, none of the soccer players were sanctioned. However, elite athletes have to face severe consequences when testing positive for a prohibited anabolic agent and sufficient supporting information corroborating the scenario of inadvertent ingestion are required to be acquitted from anti‐doping rule violations. Hence, governmental contribution is urgently needed to combat the illegal use of clenbuterol in stock breading. Copyright © 2013 John Wiley & Sons, Ltd.     

N,N‐dimethyl‐2‐phenylpropan‐1‐amine – new designer agent found in athlete urine and nutritional supplement

Reports of new designer agents banned in sport being detected in supplements widely available for athletes are constantly emerging. The task of anti‐doping laboratories is to control athletes for the presence of substances listed by the World Anti‐Doping Agency (WADA) and those that are structurally/biologically similar to them. Recently, a new designer stimulant, N,N‐dimethyl‐2‐phenylpropan‐1‐amine (NN‐DMPPA), was detected by the WADA accredited anti‐doping laboratory in Warsaw during routine anti‐doping control. The urine samples from four athletes were analyzed in the screening method for stimulants and narcotics and the presence of NN‐DMPPA was detected. The identity of NN‐DMPPA was confirmed by gas chromatography‐mass spectrometry using a synthesized reference standard. The measured concentrations of NN‐DMPPA were between 0.51 and 6.51 µg/mL. The presence of the NN‐DMPPA compound has been detected in the ‘nutritional supplement’ NOXPUMP that had been purchased in a store in Poland. NN‐DMPPA at 121.7 µg/g was indicated in the investigated supplement together with another banned stimulant β‐methylphenethylamine. The presence of this new stimulant was not indicated on the labelling of the supplement, a situation which is not unusual within this market. Thus, it is important to make athletes aware of the risk related to the use of supplements. Moreover, specific legistation dealing with the commercialization of drugs banned for sport should be undertaken. Copyright © 2014 John Wiley & Sons, Ltd.     

Codeine influences the serum and urinary profile of endogenous androgens but does not interact with the excretion rate of administered testosterone

Today's doping tests involve longitudinal monitoring of urinary steroids including the testosterone glucuronide and epitestosterone glucuronide ratio (T/E) in an Athlete Biological Passport (ABP). The aim of this study was to investigate the possible influence of short‐term use of codeine on the urinary excretion of androgen metabolites included in the steroidal module of the passport prior to and after the co‐administration with testosterone. The study was designed as an open study with the subjects being their own control. Fifteen healthy male volunteers received therapeutic doses of codeine (Kodein Meda) for 6 days. On Day 3, 500 mg or 125 mg of testosterone enanthate (Testoviron®‐Depot) was administered. Spot urine samples were collected for 17 days, and blood samples were collected at baseline, 3, 6, and 14 days after codeine intake. The circulatory concentration of total testosterone decreased significantly by 20% after 3 days' use of codeine (p = 0.0002) and an atypical ABP result was noted in one of the subjects. On the other hand, the concomitant use of codeine and testosterone did not affect the elevated urinary T/E ratio. In 75% of the individuals, the concentration of urinary morphine (a metabolite of codeine) was above the decision limit for morphine. One of the participants displayed a morphine/codeine ratio of 1.7 after codeine treatment, indicative of morphine abuse. In conclusion, our study shows that codeine interferes with the endogenous testosterone concentration. As a result, the urinary steroid profile may lead to atypical findings in the doping test.     

Enantioselective disposition of (R)‐salmeterol and (S)‐salmeterol in urine following inhaled dosing and application to doping control

Salmeterol (USAN, INN, BAN) is a long‐acting beta2‐adrenoceptor agonist (LABA) widely used in the treatment of airways disease. Although salmeterol is permitted via inhalation by athletes and supratherapeutic dosing may enhance performance, no urine threshold has been established by the World Anti‐Doping Agency (WADA). Salmeterol is a chiral compound consisting of (R)‐ and (S)‐enantiomers, normally administered as racemic (rac‐ ) mixture via inhalation. Levels of rac‐ salmeterol in urine are often below detectable levels and there is surprisingly little information regarding the enantioselectivity of salmeterol pharmacokinetics. In this study, subjects inhaled either 50 (n = 6) or 200 µg (n = 4; generally regarded as maximum therapeutic dose) of salmeterol and urine was then collected for 24 h and analyzed by enantioselective ultra performance liquid chromatography‐tandem mass spectrometry (UPLC‐MS/MS). Maximum rac‐ salmeterol urine concentrations were obtained at 2 h for both doses with medians of 0.084 ng/mL after the 50 µg dose and 2.1 ng/mL after the 200 µg dose, with an individual maximum of 5.7 ng/mL. Levels were detectable at 24 h for both doses. Salmeterol displayed enantioselective pharmacokinetics, with a mean ± SD log (S):(R) = 0.055 ± 0.025 (P < 0.0001) equivalent to (S):(R) of 1.13. In conclusion, rac‐ salmeterol by inhalation exhibits modest enantioselectivity in urine following single dose administration and can be detected following a single 50 µg dose for up to 24 h after inhalation. The present findings are of relevance if a urine threshold limit is to be introduced for salmeterol on the list of prohibited substances. The application of an enantiomer ratio analysis may offer improved discriminatory detection capability for doping control analysis applications. Copyright © 2016 John Wiley & Sons, Ltd.     

Unambiguous identification and characterization of a long‐term human metabolite of dehydrochloromethyltestosterone

In doping control analysis, the characterization of urinary steroid metabolites is of high interest for a targeted and long‐term detection of prohibited anabolic androgenic steroids (AAS). In this work, the structure of a long‐term metabolite of dehydrochloromethyltestosterone (DHCMT) was elucidated. Altogether, 8 possible metabolites with a 17α‐methyl‐17β‐hydroxymethyl – structures were synthesized and compared to a major DHCMT long‐term metabolite detected in reference urine excretion samples. The confirmed structure of the metabolite was 4α‐chloro‐18‐nor‐17β‐hydroxymethyl‐17α‐methyl‐5α‐androst‐13‐en‐3α‐ol.     

Development of in‐house materials for the verification of specific gravity measurements: Homogeneity,stability, and proficiency studies

We developed and evaluated the properties of in‐house urine reference materials for the verification of laboratory refractometers, which are frequently used in clinical chemistry and doping testing laboratories. Urine was gathered from 26 healthy volunteers (16 male 30 ± 5 years old and 10 female 29 ± 4 years old), from which two urine batches were obtained: one with a low specific gravity (1.012± 0.003) and the other with a high specific gravity (1.027 ± 0.003). Homogeneity studies were conducted over 20 consecutive days. For short‐term stability studies, aliquots of both urine batches were stored at ?20 ± 2°C; 3 ± 2°C; 20 ± 2°C; 45 ± 2°C for 0, 2, 7, 14 and 35 days, under both light and dark conditions. Similarly, another study was conducted to measure the long‐term stability of urine at ?20 ± 2°C, over a 24‐month evaluation period. Our data showed that the urine was homogeneous and stable at ?20 ± 2°C, 3 ± 2°C, 20 ± 2°C, and 45 ± 2°C under both light and dark conditions. In all cases, the urine was evaluated by specific gravity and no statistically significant differences (p ≤ 0.05) were recorded. Additionally, a proficiency test was conducted in collaboration with 15 ISO/IEC 17025 accredited laboratories, and z‐scores and performance factors were evaluated. These data indicate that this material could be used for the verification of refractometers.     

Enantioselective disposition of (R,R)‐formoterol, (S,S)‐formoterol and their respective glucuronides in urine following single inhaled dosing and application to doping control

Formoterol is a long‐acting beta2‐adrenoceptor agonist (LABA) used for the treatment of asthma and exercise‐induced bronchoconstriction. Formoterol is usually administered as a racemic (rac‐) mixture of (R,R)‐ and (S,S)‐enantiomers. While formoterol is restricted by the World Anti‐Doping Agency (WADA), inhalation of formoterol is permitted to a predetermined dose (54 μg/24 hours) and a urine threshold of 40 ng/mL. However, chiral switch enantiopure (R,R)‐formoterol is available, effectively doubling the therapeutic advantage for the same threshold. The aim of this study was to investigate whether formoterol exhibits enantioselective urinary pharmacokinetics following inhalation. Six healthy volunteers were administered a 12 μg inhaled dose of rac‐formoterol. Urine was collected over 24 hours and analyzed by enantioselective ultra‐performance liquid chromatography?tandem mass spectrometry (UPLC?MS/MS) assay. Total (free drug plus conjugated metabolite) median (min‐max) rac‐formoterol urine levels following inhalation were 1.96 (1.05–13.4) ng/mL, 1.67 (0.16–9.67) ng/mL, 0.45 (0.16–1.51) ng/mL, 0.61 (0.33–0.78) ng/mL, and 0.17 (0.08–1.06) ng/mL at 2, 4, 8, 12, and 24 hours, respectively, well below the 2019 urine threshold. The proportion of conjugation differed between enantiomers with glucuronide conjugation much greater for (R,R)‐formoterol (around 30%–60% of total) compared to (S,S)‐formoterol (0%–30%). There was clear evidence of inter‐individual enantioselectivity observed in the ratios of (R,R):(S,S)‐formoterol, where (S,S)‐ was predominant in free formoterol, and (R,R)‐ predominant in the conjugated metabolite. In conclusion, rac‐formoterol delivered by inhalation exhibits enantioselective elimination in urine following single‐dose administration. Enantioselective assays should be employed in doping control to screen for banned beta2‐agonist chiral switch products such as (R,R)‐formoterol, and total hydrolyzed rac‐formoterol is warranted to account for inter‐individual differences in enantioselective glucuronidation.     

Pharmacokinetics and metabolism of [3H]-pipethiaden in healthy volunteers.

Six healthy volunteers participated in a single-dose study of pharmacokinetics and metabolism of oral administration of [3H]-pipethiaden (1 mg). Plasma levels of total radioactivity, urinary excretion and metabolism were analyzed by liquid scintillation counting and radio-TLC. The mean peak plasma concentration of radioactive metabolites was 4.9 ng eq/ml, and the mean elimination half life was 11.5 h. 34% of radioactivity was recovered in 4 days in urine, with only 0.4% present as unchanged drug. Pipethiaden was extensively metabolized by S-oxidation, N-demethylation, and N-oxidation.     

Pharmacokinetic investigation of oral and IV dihydroergotamine in healthy subjects

Summary A new radioimmunoassay (RIA) for the specific measurement of dihydroergotamine (DHE), sufficiently sensitive for the determination of low plasma concentrations, has been used to investigate the pharmacokinetics of unchanged DHE. In a randomized crossover trial, eight healthy male volunteers received single doses of DHE 5 mg, 10 mg and 20 mg orally and 0.1 mg and 0.5 mg intravenously. It was possible to determine plasma concentrations and urinary excretion of DHE over the following 48 h. A long terminal plasma elimination phase of unchanged DHE (half-life 15 h) was found. A similar terminal elimination half-life was also calculated from urine data. The multi-exponential decline in plasma DHE with a long terminal half-life suggests that distribution into a deep compartment contributes to the long-lasting effect of the drug. Plasma protein binding was 93%. Despite extensive tissue distribution (V_z=33 l/kg) and a high plasma clearance (CL_P=2l/min), dose-independent linear pharmacokinetics was observed. The present assay was at least 20-times more specific than the polyvalent RIA used previously and appears suitable to explore the pharmacokinetics of unchanged DHE in patients on low-dose therapy. The long terminal elimination half-life of DHE only reported previously in studies using ³H-labelled drug, and considered to be due to metabolites, was also true for the parent compound. This, in addition to the sustained pharmacological activity of the 8-hydroxy metabolite already shown, provides a further explanation for the long duration of action of DHE in animals and man.     

Safety,Tolerability and Pharmacokinetics of TAS‐108, a Novel Anti‐Oestrogen,in Healthy Post‐Menopausal Japanese Women: A Phase I Single Oral Dose Study

Abstract: TAS‐108 is a novel steroidal anti‐oestrogen, expected to be useful for the treatment of breast cancer. The present study was conducted to investigate the safety, tolerability and pharmacokinetics of TAS‐108 following the administration at a single oral dose of 40 mg to up to 120 mg in 12 post‐menopausal women and the effect of food on the pharmacokinetics of the drug. All adverse events were mild and involved transient symptoms that resolved without therapeutic intervention. TAS‐108 was readily absorbed and plasma levels of TAS‐108 steadily declined, apparently in a multi‐exponential manner. C_max and AUC_0‐12 were proportionally increased with increasing dose of TAS‐108. The C_max and AUC_0‐t of TAS‐108 and its metabolite, deEt‐TAS‐108, were significantly increased to approximately 150% when TAS‐108 was administered after a meal. Food did not affect the elimination half‐life of TAS‐108 or its metabolites. In this escalating dose‐study of TAS‐108, the drug was well tolerated by healthy post‐menopausal Japanese women. The pharmacokinetics of TAS‐108 indicated dose proportionality, and its bioavailability was significantly increased by food intake.     

Pilot study on the effects of intravesical oxybutynin hydrochloride instillations on the validity of doping control urine samples

According to class M2.1 of the World Anti‐Doping Agency (WADA) Prohibited List, the manipulation of doping control urine samples to alter their integrity and validity is prohibited both in‐ and out‐of‐competition. However, some paraplegic athletes with an overactive bladder need to be regularly treated with anti‐cholinergic and anti‐spasmodic drugs such as oxybutynin, which are often administered intravesically to reduce the substantial side effects observed after oral application. So far, it remains unclear whether such bladder instillations have a negative impact on analytical procedures and thus represent an anti‐doping rule violation. Within this pilot study, urine samples were collected from five paraplegic athletes before and after an intravesical oxybutynin hydrochloride instillation. The samples were routinely tested for the presence of performance‐enhancing drugs and afterwards fortified with 25 model compounds representing different classes of doping agents (anabolic agents, cannabinoids, diuretics, glucocorticoids, hormone and metabolic modulators, and stimulants) at low and medium concentrations. Additionally, the pH value and specific gravity were measured and the presence of oxybutynin was qualitatively determined by gas chromatography?mass spectrometry (GC–MS). In initial testing procedures, all samples were tested negative. Oxybutynin was present in most of the samples but found to have no significant effect on the detectability of the 25 model compounds subsequently added to each urine specimen. Therefore, it can be concluded that intravesical instillations with oxybutynin hydrochloride do not alter the integrity and validity of doping control urine samples.     

DNA typing for personal identification of urine after long‐term preservation for testing in doping control

When the tampering of a urine sample is suspected in doping control, personal identification of the sample needs to be determined by short tandem repeat (STR) analysis using DNA. We established a method for extracting DNA from urine samples stored at −20 °C without using any additives or procedures, which is consistent with how samples are required to be managed for doping control. The method, using the Puregene® Blood Core kit followed by NucleoSpin® gDNA Clean‐up or NucleoSpin® gDNA Clean‐up XS kit, does not need any special instrument and can provide a purified extract with high‐quality DNA from up to 40 mL of urine suitable for STR analysis using an AmpFl STR® Identifiler® PCR amplification kit. Storing urine at −20 °C is detrimental to the stability of DNA. The DNA concentration of preserved urine could not be predicted by specific gravity or creatinine level at the time of urine collection. The DNA concentration of a purified extract (10 μL) was required to be >0.06 ng/μL to ensure a successful STR analysis. Thus, the required extraction volumes of urine preserved for 3–7 years at −20 °C were estimated to be 30 mL and 20 mL to succeed in at least 86% of men and 91% of women, respectively. Considering the long half‐life of DNA during long‐term preservation, our extraction method is applicable to urine samples stored even for 10 years, which is currently the storage duration allowed (increased from 8 years) before re‐examination in doping control. Copyright © 2016 John Wiley & Sons, Ltd.     

Pharmacokinetics, pharmacology of atenolol and effect of renal disease.

1. The pharmacokinetics of intravenous and oral atenolol (50 mg) in six healthy volunteers was studied. Plasma, saliva and urine were collected up to 24 h after each dose. 2. There was no significant difference in atenolol half-life when administered by the two routes. Bioavailability of the orally administered atenolol was 50%. 3. Atenolol levels in saliva required about 2 h to reach equilibrium with plasma drug levels. 4. A comparison between the pharmacokinetics and pharmacology of atenolol was made in twelve healthy subjects. 5. Dose-independent pharmacokinetics were observed. Reductions in resting heart rate and arterial blood pressure were proportional to either the logarithm of dose or area under the plasma concentration time curve or cumulative urinary atenolol excretion. 6. Plasma elimination half-life in five subjects with renal failure was prolonged.