Detecting new designer drugs

A new method of drug testing developed by researchers at RTI International makes it possible to detect a wider range of synthetically produced ‘designer’ drugs.

Designer drugs - which include the currently popular products known as ‘spice’ or ‘bath salts’ - are a new form of drugs that are easy to manufacture and difficult to recognise using traditional testing methods.

Traditional tests, which use targeted mass spectrometry to match a compound’s chemical make-up with that of a known drug, can’t identify many of these new synthetic drugs.

Because these substances are continually being developed, many of them are not yet classified as illegal, but they provide a high similar to the traditional substance they are imitating. RTI’s new method has the potential to aid law enforcement in the detection and control of this growing area of drug abuse.

Instead of relying on an exact match, RTI’s approach looks more generally for compounds whose fractional mass - the compound’s molecular weight that lies to the right of the decimal point - is similar to that of a known drug.

“Detecting designer drugs is challenging because as bans on specific compounds go into effect, manufacturers can substitute a closely related substance, creating a constantly moving target,” said Megan Grabenauer, PhD, a research chemist at RTI and lead investigator of the study. “But while the structure of designer drugs can be altered to avoid detection, the fractional mass stays relatively stable, making it a useful marker for identification.”

In a pilot study, published in Analytical Chemistry, researchers tested 32 herbal incense samples for synthetic cannabinoids, which produce psychotropic effects similar to those of cannabis but with more common and severe side effects, which include agitation, hallucinations, seizures and panic attacks.

Using high-resolution mass spectrometry and mass defect filtering, the researchers analysed the fractional masses of all components in each sample to determine if any of them were similar to that of JWH-018 (0.1858 dalton), a banned synthetic cannabinoid.

The researchers found that each of the samples contained at least one synthetic cannabinoid and some contained multiple types. Several were unexpected new compounds that would have been missed by traditional tests.

“The benefit to this approach over traditional targeted analyses is that it gives insight into the identities of components of an unknown sample,” said Brian Thomas, PhD, Senior Director of Analytical Chemistry and Pharmaceutics at RTI and one of the paper’s co-authors. “Additional tests must be run for confirmation, but the method provides valuable information about the compound’s possible identity, and a starting place for selection of an appropriate reference standard.”