Acid test: can the detection of LSD metabolites prolong LSD’s detectability?

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  • Published: Sep 1, 2016
  • Author: Ryan De Vooght-Johnson
  • Channels: HPLC
thumbnail image: Acid test: can the detection of LSD metabolites prolong LSD’s detectability?

Double-edged blade

Despite its outright ban, LSD still remains the most used psychedelic worldwide. Clinical and forensic toxicologists are troubled by its elusive nature, which limits their investigations. However, even though LSD itself is elusive, it tends to leave behind markers of its presence.

‘In a dreamlike state, with eyes closed, I perceived an uninterrupted stream of fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colours,’ the Swiss chemist Albert Hofmann mused of his first inadvertent, acid-fuelled trance. ‘After some two hours, this condition faded away.’

Five years before in Switzerland in 1938 Hofmann had chanced upon this semi-synthetic psychedelic while tinkering with derivatives of lysergic acid, a base template provided by the parasitic rye fungus, Claviceps purpurea. His toying, it would later turn out, would fix the psychoactive component, creating lysergic acid diethylamide—a drug known today as LSD.

Spurred by his serendipitous epiphany—allegedly by absorption through his fingertips—Hoffman consumed 250 µg of the nascent hallucinogen days later. ‘I was aware that LSD would have to be in use in pharmacology…and especially in psychiatry,’ Hoffmann jotted into his notebook.

Indeed, it was, and the 1950s saw LSDs adoption by the medical community. Its ability to induce psychosis and digest our emotions, psychiatrists envisioned, would complement psychotherapy. Meanwhile, partygoers and counter-culturists of the swinging 1960s also exploited its mind-bending properties, leading to its prohibition worldwide on the back of health concerns for even very small dosages.

Elusive

Despite its outright ban, the Class-A drug still remains the most used psychedelic worldwide. Clinical and forensic toxicologists are troubled by its elusive nature, which limits their investigations.

‘Analysis of LSD represents a major challenge,’ Dr Steuer and colleagues wrote in a paper published in Drug Testing and Analysis, citing its ‘instability, low drug concentrations’—as little as 25 to 200 μg is enough to alter consciousness—and ‘short detection windows.’

Even though LSD itself is elusive, it tends to leave behind markers of its presence. The iso-LSD diastereomer of LSD, for example, forms during its synthesis and our body invariably metabolises LSD into an array of compounds, including 2-oxo 3-hydroxy-LSD (oxo-HO-LSD) and N-desmethyl-LSD (nor-LSD). But can the detection of these metabolites extend LSD’s detection window? The Swiss-based scientists set out to answer this question.

In their pursuit of a novel, quick yet sensitive assay for the determination of LSD and derivatives, they opted for tandem mass spectrometry (MS/MS) because of its undisputed specificity, and downscaled to microflow liquid chromatography (MFLC) to push the boundaries of sensitivity. This, they reasoned, would be necessary for detecting the traces of LSD concealed in plasma.

MFLC-MS/MS

Their workflow consisted of a quick-and-simple solid-phase extraction (SPE) of analytes from plasma, followed by loading onto a C18 silica column and resolving over a ~3-minute-long, acidified aqueous-to-organic microflow gradient. Resolved analytes were then fed into a Qtrap, bombarded with an electrospray of protons, and the mass analysers monitored the multiple ion reactions as they fragmented. The most abundant of these fragments quantitated each derivative, whilst the next two intense signals were used for identification.

With stringent applications in mind, Dr Steuer and colleagues validated their method in line with recommendations by the Society of Toxicological and Forensic Chemistry. First of all, their MFLC-MS/MS assay could recover 73.4–104.9% of 0.02 ng of derivatives spiked into 1 mL of plasma and 88.6–107.4% of 15 ng/mL standards, whilst the variabilities in matrix influences from six different plasmas were within 20%.

A regression curve of seven standards, spanning the spectrum of recorded doses, enabled the quantitation of derivatives. This ranged from the 0.01 ng/mL achieved with recreational use to the f 20 ng/mL that an overdose can bring about. The authors confidently state their limit of quantitation for all derivatives at 0.1 ng/mL, reasoning that their SPE and MFLC with a signal-to-noise level of 10:1. This achievement—with only 500 μL of plasma—raises the bar for LSD analysis.

Finally, the developed method was used to analyse plasma drawn from study participants receiving controlled dosages of LSD. Whilst the half-lives of the derivatives (7.4–12 hours) far exceeded that of LSD (4.2), the authors concluded that testing for these derivatives ‘seems not be constructive due to their very low concentrations’. Can the detection of LSD metabolites prolong LSD’s detectability? Seemingly not yet.

Related Links

Drug Testing and Analysis, 2016, Early View paper. Steuer et al.. Development and validation of an ultra-fast and sensitive microflow liquid chromatography-tandem mass spectrometry (MFLC-MS/MS) method for quantification of LSD and its metabolites in plasma and application to a controlled LSD administration study in humans.

Article by Ryan De Vooght-Johnson

The views represented in this article are solely those of the author and do not necessarily represent those of John Wiley and Sons, Ltd.

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