A NEW generation of illicit street drugs are virtually undetectable to authorities and only start working once they’re digested and broken down.
Called prodrugs, their particular molecular structure makes use of our body’s metabolism, meaning they work differently to typical recreational drugs.
Most illicit drugs interact with brain cell receptors and last for a short amount of time, before being transformed into inactive or less active chemicals that are flushed out of the body through urine, according to Julio de Carvalho Ponce, a lecturer in forensic science at the University of Winchester.
But these new generation substances only are only converted into drugs once they’ve been broken down by enzymes in the digestive system or gone through other chemical reactions in the body.
These reactions will remove a small part of the substance’s molecular structure, after which the prodrugs begin to taken an effect.
Basically, they’re not recognisable as drugs – and don’t work like drugs – until after they’ve entered the body and been broken down.
For example, ALD-52 (1-acetyl-LSD) is a prodrug that becomes LSD inside the body after the removal of two carbon and one oxygen atom.
And because they don’t fit recognisable compounds for recreational drugs, they’ve been very hard for law enforcement to detect and seize.
As Dr Ponce puts it, this feature has allowed drug traffickers “to trick enforcement agencies”.
Writing for The Conversation, Dr Ponce explained: “Police forces need reference samples to compare the drug with, or advanced equipment to discover its molecular structure.
“Since the list of these compounds is not known and minute chemical changes can lead to different patterns to be analysed, these new drugs are easy to miss.”
They’re also hard to identify in biological samples, such as blood, urine and saliva, as well as in laboratory testing, due to the conversion process that needs to happen for them to be activated.
According to Dr Ponce, prodrugs are not a new technology as between five and seven per cent of approved drugs use it.
But their use in street drugs is a relatively new phenomenon, he said.
“Although some reports indicate that ALD-52 has been around since the 1960s, it was first officially detected in 2016 by the authorities in France,” he wrote.
“The UK government was quick to list this prodrug as a controlled substance as early as 2014, even though there were no reports of drug seizures or known harms. Since then, many other prodrugs have been identified.”
The party drug GHB also has a prodrug equivalent called GBL (gamma-butyrolactone) that’s usually sold as a cleaning agent, according to Dr Ponce.
The UK classified it as a class B drug, alongside cannabis and ketamine, in 2022, he said.
The forensic scientist added: “Drug traffickers have also developed ways to mask illegal MDMA (ecstasy) by adding a small molecule that can be removed by chemical reactions or in the stomach through contact with gastric acid.”
Dr Ponce noted that due to the difficulty detecting them, prodrug seizures are much smaller and less frequent than ones for cocaine, cannabis or heroin.
But he said their slow spillage into the drug market over recent years “serve as a warning sign of potentially changing trends in the illicit drug market”.
Scientists still don’t exactly know how intense they are and how long they last once taken and there’s also difficulty in prosecuting people who supply these prodrugs.