Scientists devise tests for new drug

PARIS - German scientists recently reported they had devised a test to pinpoint a new class of drugs that, it is feared, could become a tempting choice for sports cheats.

PARIS - German scientists recently reported they had devised a test to pinpoint a new class of drugs that, it is feared, could become a tempting choice for sports cheats.

The drugs - currently only experimental - belong to a class of medical compounds called benzothiazepines. They are being tested in clinical trials on human volunteers to see whether they can treat irregular heartbeat, a condition called cardiac arrhythmia, and have yet to be licensed.

Researchers have been surprised, though, to find that the drugs also have the unusual side effect, among lab mice, of building and sustaining muscle power.

This has prompted concerns that they could be the future drug of choice for endurance athletes.

In a study published in a new British journal, Drug Testing and Analysis, a team led by Mario Thevis of the German Sports University in Cologne said they had established a method for detecting the molecular "fingerprint" of the two benzothiazepines in trials.

Thevis said healthy human volunteers provided samples of urine that were then spiked with the two drugs and with their metabolised components.

The telltale signature of the drugs, JTV-510 and S-107, and their breakdown products was spotted by high resolution mass spectrometry - a standard machine in a drug-testing lab - in concentrations as low as 0,1 nanograms per millilitre.

Benzothiazepines are not on the World Anti-Doping Agency's list of prohibited substances, Thevis said. But the successful test means if the drugs are included on the list one day, drug cheats could be spotted early on, he said.

"If we start developing a detection method in two or three years when this drug becomes commercially available, athletes that might be tempted to misuse it will have had an opportunity for several years," he said.

The test could be easily carried out on standard urine samples, where the trace of the drugs is likely to linger "for days, probably weeks", said Thevis.

Benzothiazepines work on so-called calcium channels in cells in muscle fibres. In order to function properly, these cells require a big differential in levels of calcium between the inside and the outside of the cell.

After a long period of exercise, though, the calcium channels become "leaky" and do not close properly. This disrupts the difference in calcium levels and causes the cell to malfunction.

"In other words, the channel is like a valve, and if the valve is not closing properly, there's a little leak, and the muscle is not contracting as it should," said Thevis. "In your heart, this causes arrhythmia, and in muscles, it causes fatigue."

Thevis said a typical path taken by cheats was to copy a drug, such as an anabolic steroid, and then modify it slightly so that it retained the same effect but became harder to detect. - Sapa-AFP

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