[Ophthalmic drug therapy in professional athletes-what is allowed, what is doping?] / Ophthalmologische Arzneitherapie bei Profisportlern ­ Was ist erlaubt, was Doping?

At first sight, ophthalmic drugs are not necessarily suspected of being used as performance-enhancing agents in competitive sports. However, there are some restrictions that must be noted, especially when certain drugs are taken orally. A structured analysis of the doping relevance of ophthalmic drugs was performed on the basis of a literature review, taking into account the current guidelines of the National Anti-Doping Agency of Germany and the World Anti-Doping Agency. Use of the most common ophthalmological drug groups is possible without restrictions, especially in the case of topical application. An exception is the oral use of diuretics, which is prohibited at all times. For glucocorticoids, topical application to the eye is allowed, but oral application is prohibited in competition. A similar restriction applies to the use of epinephrin, for which all forms of systemic application are prohibited in competition. When taking beta-blockers, the sport being played is the determining factor: use is prohibited in billiards, archery, darts, golf, motor sports, shooting sports, skiing/snowboarding, ski jumping, freestyle aerials/half pipe, snowboard half pipe/big air, and underwater sports. For shooting and archery, beta-blockers are also prohibited outside of competitions. Athletes with pre-existing ophthalmological conditions should seek comprehensive advice from an ophthalmologist before using any medication, and together they should choose a permissible active ingredient, consider the appropriate route of application, and, if necessary, apply for a Therapeutic Use Exemption. It is currently not known how many of the national and international athletes have to be treated with eye drops.

Preliminary data on the potential for unintentional antidoping rule violations by permitted cannabidiol (CBD) use.

According to the World Anti-Doping Agency (WADA) regulations, cannabinoids use is prohibited in competition except for cannabidiol (CBD) use. For an adverse analytical finding (AAF) in doping control, cannabinoid misuse is based on identification of the pharmacologically inactive metabolite 11-nor-delta-9-carboxy-tetrahydrocannabinol-9-carboxylic acid (carboxy-THC) in urine at a concentration greater than 180 ng/ml. All other (minor) cannabinoids are reported as AAF when identified, except for CBD that has been explicitly excluded from the class of cannabinoids on WADA's Prohibited List since 2018. However, due to the fact that CBD isolated from cannabis plants may contain additional minor cannabinoids, the permissible use of CBD can lead to unintentional violations of antidoping regulations. An assay for the detection of 16 cannabinoids in human urine was established. The sample preparation consisted of enzymatic hydrolysis of glucuronide conjugates, liquid-liquid extraction, trimethylsilylation, and analysis by gas chromatography/tandem mass spectrometry (GC-MS/MS). Spot urine samples from CBD users, as well as specimens obtained from CBD administration studies conducted with 15 commercially available CBD products, were analyzed, and assay characteristics such as selectivity, reproducibility of detection at the minimum required performance level, limit of detection, and limit of identification were determined. An ethical committee approved controlled single dose commercially available CBD products administration study was conducted to identify 16 cannabinoids in urine samples collected after ingestion or application of the CBD products as well as their presence in spot urine samples of habitual CBD users. Variable patterns of cannabinoids or their metabolites were observed in the urine samples, especially when full spectrum CBD products were consumed. The presence of minor cannabinoids or their metabolites in an athlete's in-competition urine sample represents a substantial risk of an antidoping rule violation.

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.

2-Amino-5-benzoyl-4-phenylthiazoles: Development of potent and selective adenosine A1 receptor antagonists.

A series of 2-amino-5-benzoyl-4-phenylthiazole derivatives was investigated in radioligand binding studies at adenosine receptor (AdoR) subtypes with the goal to obtain potent and A(1)-selective antagonists. Acylation of the 2-amino group was found to be crucial for high A(1) affinity. The best compound of the present series was 2-benzoylamino-5-p-methylbenzoyl-4-phenylthiazole (16 m) showing a K(i) value of 4.83 nM at rat and 57.4 nM at human A(1) receptors combined with high selectivity versus the other AdoR subtypes. The compound behaved as an antagonist in GTP shift assays at A(1) receptors. Compound 16 m may serve as a new lead structure for the development of second-generation non-xanthine-derived A(1) antagonists which have potential as novel drugs.

Development of potent and selective inhibitors of ecto-5'-nucleotidase based on an anthraquinone scaffold.

ecto-5'-Nucleotidase (eN, CD73) plays a major role in controlling extracellular adenosine levels. eN inhibitors have potential as novel drugs, for example, for the treatment of cancer. In the present study, we synthesized and investigated a series of 55 anthraquinone derivatives as potential inhibitors of eN, 11 of which are novel compounds and another 11 of which had previously been described but have now been synthesized by an improved method. We identified several potent inhibitors of rat eN. The most potent compounds were 1-amino-4-[4-fluoro-2-carboxyphenylamino]-9,10-dioxo-9,10-dihydroanthracene-2-sulfonate (45, PSB-0952, K(i) = 260 nM) and 1-amino-4-[2-anthracenylamino]-9,10-dioxo-9,10-dihydroanthracene-2-sulfonate (52, PSB-0963, 150 nM), with 52 being the most potent eN inhibitor described to date. Selected compounds were further characterized and found to exhibit a competitive mechanism of inhibition. Investigations of ecto-nucleoside triphosphate diphosphohydrolases (NTPDases) and the P2Y receptor subtypes P2Y(2), P2Y(4), P2Y(6), and P2Y(12) showed that compound 45 exhibited the highest degree of selectivity (>150-fold).

1-alkyl-8-(piperazine-1-sulfonyl)phenylxanthines: development and characterization of adenosine A2B receptor antagonists and a new radioligand with subnanomolar affinity and subtype specificity.

A new series of 1-alkyl-8-(piperazine-1-sulfonyl)phenylxanthines was designed, synthesized, and characterized in radioligand binding and functional assays at A(2B) adenosine receptors. A(2B) antagonists with subnanomolar affinity and high selectivity were discovered. The most potent compounds were 1-ethyl-8-(4-(4-(4-trifluoromethylbenzyl)piperazine-1-sulfonyl)phenyl)xanthine (24, PSB-09120, K(i) (human A(2B)) = 0.157 nM) and 8-(4-(4-(4-chlorobenzyl)piperazine-1-sulfonyl)phenyl)-1-propylxanthine (17, PSB-0788, K(i) (human A(2B)) = 0.393 nM). Moreover, 8-(4-(4-(4-chlorophenyl)piperazine-1-sulfonyl)phenyl)-1-propylxanthine (35, PSB-603) was developed as an A(2B)-specific antagonist exhibiting a K(i) value of 0.553 nM at the human A(2B) receptor and virtually no affinity for the human and rat A(1) and A(2A) and the human A(3) receptors up to a concentration of 10 microM. A tritiated form of the compound was prepared as a new radioligand and characterized in kinetic, saturation, and competition studies. It was shown to be a useful pharmacological tool for the selective labeling of human as well as rodent A(2B) receptors (K(D) human A(2B) 0.403 nM, mouse A(2B) 0.351 nM).

Selective nucleoside triphosphate diphosphohydrolase-2 (NTPDase2) inhibitors: nucleotide mimetics derived from uridine-5'-carboxamide.

Ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases, subtypes 1, 2, 3, 8 of NTPDases) dephosphorylate nucleoside tri- and diphosphates to the corresponding di- and monophosphates. In the present study we synthesized adenine and uracil nucleotide mimetics, in which the phosphate residues were replaced by phosphonic acid esters attached to the nucleoside at the 5'-position by amide linkers. Among the synthesized uridine derivatives, we identified the first potent and selective inhibitors of human NTPDase2. The most potent compound was 19a (PSB-6426), which was a competitive inhibitor of NTPDase2 exhibiting a K i value of 8.2 microM and selectivity versus other NTPDases. It was inactive toward uracil nucleotide-activated P2Y 2, P2Y 4, and P2Y 6 receptor subtypes. Compound 19a was chemically and metabolically highly stable. In contrast to the few known (unselective) NTPDase inhibitors, 19a is an uncharged molecule and may be perorally bioavailable. NTPDase2 inhibitors have potential as novel cardioprotective drugs for the treatment of stroke and for cancer therapy.