Application of a Pyroprobe to Simulate Smoking and Metabolic Degradation of Abused Drugs Through Analytical Pyrolysis^*

Abstract

Smoking of illicit drugs can produce unique metabolic biomarkers. Smoking conditions can be partially modeled via pyrolysis, a process that decomposes a chemical compound by extreme heat. Pyrolytic decomposition was found to be useful as a limited metabolic mimic in that analytical pyrolysis can be used to generate some of the same compounds produced by metabolic degradation. This project focused on the pyrolysis of cocaine and methamphetamine using a pyroprobe coupled with a GC/MS and more generally, potential applications of pyrolysis to forensic toxicology. Common diluents including lidocaine, caffeine, and benzocaine were pyrolyzed in mixtures with cocaine and methamphetamine. Correlations between pyrolytic and metabolic degradations revealed that this method has the capability to produce some of the reported metabolites such as norcocaine and cocaethylene for cocaine, and amphetamine for methamphetamine. The results demonstrate that analytical pyrolysis has the potential to identify some metabolic products and to supplement in vivo and enzymatic studies.

Pharmacological effects of methamphetamine and alpha-PVP vapor and injection

“…While previous analytical studies identified thermolytic degradants of METH that produce harmful effects and psychoactive effects (Gayton-ely et al, 2007; Sato et al, 2004; Sekine and Nakahara, 1987), the degree to which these degradants (or others) were generated under the heating conditions used in the present study remains unknown. Results show subtle route of administration differences such as alterations in time course, and potential route by sex interactions in the FOB.…”

“…The synthetic cathinone mephedrone creates degradants that cause lachrymation and respiratory irritation (Kavanagh et al, 2013). Furthermore, METH and cocaine thermolysis create psychoactive degradants including cocaethylene, amphetamine, and ephedrine (Gayton-ely et al, 2007; Sekine and Nakahara, 1987). …”

Pyrolysis of drugs of abuse: a comprehensive review

“…Similarly, the elimination of benzoic acid from the parent cocaine molecule has been shown to be temperature dependent with a trans ‐elimination being favoured at lower temperatures (200–500 °C) and a cis ‐elimination being favoured at higher temperatures . Other pyrolytic products identified include carbomethoxyccyloheptatrienes (CMCHTs, 14 , Figure )) and cocaine metabolites (norcoaine, ecgonine methylester, benzoylecgonine, and cocaethylene) . A pair of studies by Novak et al .…”

Simple method for determination of cocaine and main metabolites in urine by CE coupled to MS

“…Nevertheless, several methods for the analysis of COC and a few metabolites in biological samples have been reported in the literature, such as high-performance thin layer chromatography [3], high performance liquid chromatography with ultraviolet [3,8], fluorescence [9,10] or MS detection [11] and gas chromatography with MS [5,[12][13][14] or flame ionization detection [15]. However, it must be emphasized that none of the above literature methods contemplated the analysis of COC and all five metabolites depicted in Fig.…”

“…In order to cover a sufficiently broad range of drugs, complementary analytical techniques are often required [2]. The simultaneous determination of COC and its metabolites presents many analytical pitfalls within traditional chromatographic techniques: some metabolites are produced by heating, such as the crack use bioindicator AEME, and can be generated in the gas chromatography injector port, if operated at elevated temperatures, giving rise to artifacts [5][6][7]; other metabolites are too hydrophilic, such as AEME, AE and EME, resulting in poor retention during reversed-phase liquid chromatography analysis. Other shortcomings include the fact that many metabolites lack chromophoric moieties hindering their UV-vis/fluorescence detection.…”