Some athletes and trainers are tuned in to the drug-development pipeline, looking for the next big doping agent: experimental drugs that can boost strength and endurance but are new enough to slip under the screening radar. One scientist I spoke to for a previous piece on doping said that he still gets flooded with calls from athletes years after publishing details of a promising advance in drug development for muscular dystrophy.

In an effort to combat the abuse of new compounds before it starts, anti-doping agencies have begun working with drug companies to develop screening tests before drugs are even on the market. In last year’s Tour de France, the World Anti-Doping Agency caught several cyclists using a longer-lasting form of the endurance booster EPO (erythropoietin), called CERA. Soon after the athletes were caught, it was revealed that the agency had been working with Swiss drugmaker Roche to develop a test to detect CERA while the drug was still being tested by the U.S. pharmaceutical company Amgen.

Now German scientists announce that they have developed a test for a class of compounds called benzothiazepines, which are being developed for the treatment of heart abnormalities and have been shown to boost endurance in mice. According to a press release from Drug Testing and Analysis, the journal publishing the research,

These compounds stabilize protein channels that would otherwise “leak” calcium from muscle cells during strenuous exercise. Calcium is needed for muscle contraction and this “leaking” effect weakens the contractions and is a causal factor in muscle fatigue.

While the drugs have not yet been tested in humans, researchers say that they carry a high potential for abuse because they are easy to make.

“As soon as these drugs enter human clinical trials, there is a huge potential for them to be misused in sports. This preventive research lets us prepare before these compounds are officially launched,” says Mario Thevis, Director of the Center for Preventive Doping Research at the German Sport University of Cologne, Germany, who led the research.

The study characterises the compounds according to their weight and molecular structure. This gives the researchers a molecular “fingerprint” by which to identify the compounds. Thevis and colleagues show that, using high resolution mass spectrometry, JTV-519 and S-107 can be detected in spiked urine at concentrations as low as 0.1 nanograms per millilitre.