Isolation and characterization of a newly identified impurity in methamphetamine synthesized via reductive amination of 1-phenyl-2-propanone (P2P) made from phenylacetic acid/lead (II) acetate

Changes in methamphetamine impurity profiles induced by tert-butoxycarbonylation

Analysis of impurities in methamphetamine (MA) can be used to characterize MA seizures, investigate the relationship among MA seizures, and provide information on their synthetic routes. Recently, chemically derivatized MA, such as tert-butoxycarbonyl (t-Boc) MA, has been seized and attracted attention because routine forensic analysis methods may fail to correctly identify them. Chemical derivatization is a simple method for protection and deprotection of a compound, and protection of MA using t-Boc can be used to mask the MA. Although t-Boc derivatization might alter the impurity profile of MA, the actual changes in the impurity profile have not been investigated. In this study, changes in the MA impurity profile with tert-butoxycarbonylation were explored. MA and some typical impurities were derivatized using di-tert-butyl dicarbonate and water. Analysis of the impurities in five MA samples by gas chromatography showed that peaks both appeared and disappeared for the deprotected MA compared with the original MA. However, typical impurities important for characterizing MA seizures were conserved after derivatization and deprotection. Most of the new peaks were speculated to be contaminants introduced during derivatization and deprotection. A peak giving a mass spectrum similar to that of t-Boc MA was detected in the chromatograms of t-Boc MA and deprotected MA. Although the origin of this peak was not determined, it might be a marker for the MA involving tert-butoxycarbonylation. These results indicate that tert-butoxycarbonylation can alter the MA impurity profile; therefore, care is needed when interpreting results for derivatized MA.

The role of microorganisms in the biotransformation of psychoactive substances and its forensic relevance: a critical interdisciplinary review

Microorganisms are widespread on the planet being able to adapt, persist, and grow in diverse environments, either rich in nutrient sources or under harsh conditions. The comprehension of the interaction between microorganisms and drugs is relevant for forensic toxicology and forensic chemistry, elucidating potential pathways of microbial metabolism and their implications. Considering the described scenario, this paper aims to provide a comprehensive and critical review of the state of the art of interactions amongst microorganisms and common drugs of abuse. Additionally, other drugs of forensic interest are briefly discussed. This paper outlines the importance of this area of investigation, covering the intersections between forensic microbiology, forensic chemistry, and forensic toxicology applied to drugs of abuse, and it also highlights research potentialities.

Key points

Microorganisms are widespread on the planet and grow in a myriad of environments.Microorganisms can often be found in matrices of forensic interest.Drugs can be metabolized or produced (e.g. ethanol) by microorganisms.

Monitoring Methamphetamine in the United States. A Two Decade Review as Seen by the DEA Methamphetamine Profiling Program

A historical overview of methamphetamine profiling efforts in the United States is presented. Methamphetamine profiling has revealed key precursor and recipe strategies that have changed throughout the years. By studying different clandestine recipes and analyzing thousands of methamphetamine samples over the years, the Drug Enforcement Administration (DEA) Methamphetamine Profiling Program (MPP) has collected and reported on changes in drug quality and production trends. This review will discuss methamphetamine drug profiling trends that cover over two decades of forensic results.

Synthetic origin of illicit methylamphetamine in Australia: 2011-2020

The National Measurement Institute's Methylamphetamine Profiling Program has evolved over the last 15 years to address analytical challenges faced with changes in illicit methylamphetamine production. The program involves organic and inorganic analysis of methylamphetamine to determine the precursors and synthetic route used in manufacture. This paper discusses changes in the methylamphetamine chemical profile for samples received at this laboratory during January 2011 to December 2020. In particular, changes observed in the methylamphetamine purity, potency, synthetic route, precursor and precursor synthetic origin are discussed. Over 13,180 samples were analysed during this period consisting of samples seized on the streets and the Australian border. This paper shows correlations between methylamphetamine seizures at the Australian border with international clandestine laboratory and precursor seizures trends. As the illicit drug landscape changes so too must our approach to chemical profiling if we are to confidently determine the synthetic origin of methylamphetamine.

Investigations into the stable isotope ratios of 1-phenyl-2-propanone

Stable isotope ratio mass spectrometry (IRMS) can be used to determine the precursor and precursor origin of methylamphetamine drug samples. Previous work has shown that methylamphetamine samples can be distinguished as derived from different sources of (pseudo)ephedrine or phenyl-2-propanone (P2P) through the use of IRMS alongside conventional chemical profiling techniques. To date, limited research has been conducted to investigate whether methylamphetamine samples of differing P2P origins can be distinguished through drug profiling. This was investigated by synthesising methylamphetamine in-house in a three-step process. Two 'preprecursors' were used in this study, phenylacetic acid (PAA) and α-phenylacetoacetonitrile (α-PAAN). Using a combination of profiling techniques, it was found that methylamphetamine samples of PAA preprecursor origin and methylamphetamine samples of α-PAAN preprecursor origin can be distinguished.

Stereoselective analysis of ephedrine and its stereoisomers as impurities and/or by-products in seized methamphetamine by supercritical fluid chromatography/tandem mass spectrometry

In forensic science, drug profiling is clarifying the identity of seized drugs of abuse based on their physicochemical properties and it is applied to various drugs, including crystalline methamphetamine. Impurity analysis is particularly important in drug profiling because the impurities can be a measure for speculating how the methamphetamine was synthesized in the clandestine laboratories. However, developments in scientific techniques have allowed the synthesis of high-purity, homogeneous crystalline methamphetamine, and thus new techniques to characterize methamphetamine are needed. In this study, we developed a method for chiral separation of ephedrine and its stereoisomers by supercritical fluid chromatography. Ephedrine is a common starting compound for methamphetamine synthesis. It possesses two chiral center carbon atoms and has four stereoisomers, (1R,2S)-(-)-ephedrine, (1S,2R)-(+)-ephedrine, (1S,2S)-(+)-pseudoephedrine, and (1R,2R)-(-)-pseudoephedrine. Because the stereostructure of ephedrines contained in methamphetamine seizure reflects the starting materials and the synthetic pathways, the stereoisomer ratio will provide additional information for drug profiling. The developed method achieved rapid separation of four isomers in about 11min with low limits of detection (1pg on column). Due to a switching valve connecting a chromatograph to a mass spectrometer, dense methamphetamine sample solutions containing small amount of ephedrines could be analyzed directly with a simple pre-treatment. Using multivariate analysis, 44 real samples were objectively grouped based on stereoisomer ratio. Our method is expected to improve the profiling of crystalline methamphetamine.

A review of the newly identified impurity profiles in methamphetamine seizures

Forensic intelligence of synthetic illicit drugs suffers a problem of continuous introduction of new synthetic methods, modification of the existing routes of manufacture, and adulterations practiced by criminal networks. Impurity profiling has been indispensable in methamphetamine intelligence based on precursors, synthetic routes, and chemical modifications during trafficking. Law enforcement authorities maintain the credibility and integrity of intelligence information through constant monitoring of the chemical signatures in the illicit drug market.

Changes in the synthetic pattern result in new impurity profiles that are important in keeping valuable intelligence information on clandestine laboratories, new synthetic routes, trafficking patterns, and geographical sources of illicit Methamphetamine.

This review presents a critical analysis of the methamphetamine impurity profiles and more specifically, profiling based on impurity profiles from Leuckart, Reductive amination, Moscow, Emde, Nagai, Birch, Moscow route; a recent nitrostyrene route and stable isotope signatures. It also highlights the discrimination of ephedrine from pseudoephedrine sources and the emerging methamphetamine profiling based on stable isotopes.

Interpol review of controlled substances 2016-2019

This review paper covers the forensic-relevant literature in controlled substances from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20Papers%202019.pdf.

DARK Classics in Chemical Neuroscience: Methamphetamine

Methamphetamine has the second highest prevalence of drug abuse after cannabis, with estimates of 35 million users worldwide. The ( S)-(+)-enantiomer is the illicit drug, active neurostimulant, and eutomer, while the ( R)-(-)-enantiomer is contained in over the counter decongestants. While designated a schedule II drug in 1970, ( S)-(+)-methamphetamine is available by prescription for the treatment of attention-deficit disorder and obesity. The illicit use of ( S)-(+)-methamphetamine results in the sudden "rush" of stimulation to the motivation, movement, pleasure, and reward centers in the brain, caused by rapid release of dopamine. In this review, we will provide an overview of the synthesis, pharmacology, adverse effects, and drug metabolism of this widely abused psychostimulant that distinguish it as a DARK classic in Chemical Neuroscience.

Investigation by direct-infusion ESI-MS and GC-MS of an alleged Leuckart route-specific impurity of methamphetamine

Impurity profiling has been used as a useful tool for analyzing nearly every drug class currently known on the illicit market. Impurities present within seized samples have the potential to determine source of origin, route of synthesis used, as well as provide a useful clue into the potential reaction mechanisms that are present for each synthetic procedure. Perhaps the most well studied of these impurity profiles exists for methamphetamine, including information to more than one route of synthesis. Within the present study, a complete synthesis of methamphetamine was performed, including a reductive amination of phenylpropanone (P2P) using methylamine hydrochloride and sodium triacetoxyborohydride (STAB) rather than the conventional aluminum mercury amalgam commonly found in the literature. During the analysis of the final product from this reaction, a major impurity within the reaction, bis(1-phenylpropan-2-yl)amine (m/z 253), was detected by GC-MS as well as direct-infusion ESI-MS. This impurity has been previously reported as a Leuckart route-specific impurity. Its detection within the reductive amination of P2P points towards the use of impure methylamine hydrochloride containing some traces of acid, and provides further insight into the reductive amination of P2P. In both the Leuckart reaction and this reductive amination via STAB, the presence of acid and ammonia leads to this impurity.

Simultaneous detection and quantitation of organic impurities in methamphetamine by ultra-high-performance liquid chromatography-tandem mass spectrometry, a complementary technique for methamphetamine profiling

The analysis of organic impurities plays an important role in the impurity profiling of methamphetamine, which in turn provides valuable information about methamphetamine manufacturing, in particular its synthetic route, chemicals, and precursors used. Ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) is ideally suited for this purpose due to its excellent sensitivity, selectivity, and wide linear range in multiple reaction monitoring (MRM) mode. In this study, a dilute-and-shoot UHPLC-MS/MS method was developed for the simultaneous identification and quantitation of 23 organic manufacturing impurities in illicit methamphetamine. The developed method was validated in terms of stability, limit of detection (LOD), lower limit of quantification (LLOQ), accuracy, and precision. More than 100 illicitly prepared methamphetamine samples were analyzed. Due to its ability to detect ephedrine/pseudoephedrine and its high sensitivity for critical target markers (eg, chloro-pseudoephedrine, N-cyclohexylamphetamine, and compounds B and P), more impurities and precursor/pre-precursors were identified and quantified versus the current procedure by gas chromatography-mass spectrometry (GC-MS). Consequently, more samples could be classified by their synthetic routes. However, the UHPLC-MS/MS method has difficulty in detecting neutral and untargeted emerging manufacturing impurities and can therefore only serve as a complement to the current method. Despite this deficiency, the quantitative information acquired by the presented UHPLC-MS/MS methodology increased the sample discrimination power, thereby enhancing the capacity of methamphetamine profiling program (MPP) to conduct sample-sample comparisons.