Abuse of smoking methamphetamine mixed with tobacco. III. Urinary metabolites of N-cyanomethylmethamphetamine, a pyrolysis product formed by smoking methamphetamine in tobacco, and species difference in its metabolism between rat and mouse

Pyrolysis of drugs of abuse: a comprehensive review

This review summarizes the literature to date relating to pyrolysis and heated vapour ingestion of drugs of abuse. In this context, heating is referred to as smoking or pyrolysis, but these are generic descriptors that encompass numerous methods of vapour generation and inhalation. Depending on the amount of drug used, diluents and contaminants present, heating conditions, and the oxidative/reductive environment, many thermal decomposition products can be formed. In addition to the recognized hazard of rapid onset of pharmacological effects of the parent drug, thermal decomposition products may be pharmacologically active as well as acutely/chronically toxic. For example, several published reports have linked heroin smoking to a form of brain encephalopathy and to the development of movement disorders. Early qualitative studies focusing on the thermal decomposition of drugs have evolved into more complex investigations employing mass spectral identification, confirmation, and elucidation of formation mechanism. In most cases, thermal decomposition begins with cleavage of the weakest bond (often C-N) to generate free radicals that then form the most stable sterically favoured products. Several reports of rearrangements at higher temperatures have been identified and hint at an underlying complexity that arises from the variety of smoking methods and conditions. Given that many designer drugs such as synthetic cannabinoids are ingested primarily through smoking, this issue has taken on new importance.

Effects of amphetamine on rat embryos developing in vitro

Wistar rat embryos were explanted on Day 10.5 of gestation and exposed in vitro to amphetamine (AMP) at concentrations of 0.1, 0.4, 0.8, 1.2, or 1.6 mM for 24 h, and the direct dysmorphogenic effects of the drug on the embryos were examined by comparisons with a control group. The viability of the cultured embryos was not affected by the AMP treatment. The yolk sac diameter was reduced at AMP concentrations of 1.2 and 1.6 mM. The crown-rump length, the somite number, and the protein content of the embryos were decreased significantly at these two doses, as was the developmental score. The frequency of malformed embryos was increased significantly at the two highest concentrations. The malformations induced in treated embryos included microcephaly, neural tube defects, incomplete rotation of the body axis, and tortuous spinal cord. Abnormal histologic changes, such as derangement and necrosis of the neuroepithelial tissue, were observed in the embryos exposed to the two highest concentrations of the drug. The observed embryotoxic effects appeared to depend on the AMP concentration. Our results demonstrated the direct embryotoxic effects of AMP on rats. The direct dysmorphogenic effect of AMP might be weaker than that of methamphetamine.

Behavioral effects of N-cyanomethylmethamphetamine, a product derived from smoking methamphetamine with tobacco, in mice and rats

The stimulant effects of N-cyanomethylmethamphetamine (CMMA), a product derived from smoking methamphetamine (MA) mixed in tobacco, were studied by observing stereotyped behavior and measuring spontaneous motor activity in mice and rats over 180 min CMMA. 1.3 and 10 mg/kg IP, elicited strong stimulant-like effects which were almost equivalent to those produced by MA. Drug monitoring for 180 min in mouse and rat plasma revealed that the principal substances responsible for the stimulant effect of CMMA were MA and amphetamine (AP) which were metabolized from CMMA by the animal. There was a species difference in metabolism of CMMA between mice and rats. The major metabolites were MA and AP in mouse plasma, followed by N-formylmethamphetamine (FMA), whereas the major metabolite was FMA in rat plasma, followed by MA and AP. The differences in the stimulant effects of CMMA between mice and rats were discussed in relation to its metabolic fate in mice and rats.

Effect of haloperidol on the behavioral stimulation by N-cyanomethylmethamphetamine, a main product of smoking methamphetamine mixed with tobacco

N-Cyanomethylmethamphetamine is a main product of smoking methamphetamine mixed with tobacco. The aim of this experiment was to evaluate the effects of haloperidol on behavioral stimulation by N-cyanomethylmethamphetamine (3 mg/kg s.c.) in terms of ambulation in mice. Repeated administration of N-cyanomethylmethamphetamine, carried out 5 x at 3-day intervals, induced a sensitization to its ambulation-increasing effect. Haloperidol (0.01, 0.03, 0.1 and 0.3 mg/kg s.c.) significantly inhibited not only the acute stimulant effect of N-cyanomethylmethamphetamine but also the induction of sensitization. The dose-effect curves for the inhibitory effects of haloperidol on the N-cyanomethylmethamphetamine-induced ambulatory stimulation were almost the same between the drug-native and N-cyanomethylmethamphetamine-sensitized mice. Moreover, such behavioral characteristics of N-cyanomethylmethamphetamine; the behavioral stimulant effect, the induction of sensitization following repeated administration, and the inhibition of its effects by haloperidol, were qualitatively the same as those of methamphetamine (2 mg/kg s.c.). These results suggest that N-cyanomethylmethamphetamine possesses methamphetamine-like central stimulant effect and that D2 dopaminergic mechanisms are involved in the effect of N-cyanomethylmethamphetamine.

Characteristics of behavioural stimulant effect of N-cyanomethylmethamphetamine, a main product of smoking methamphetamine mixed with tobacco: evaluation by ambulatory activity in mice

N-cyanomethylmethamphetamine is main product of smoking methamphetamine HCl (CAS code value: 537-46-2, molar mass: 185.70 g/mol) mixed with tobacco, and has a central stimulant action. The aims of this study were to assess in terms of ambulation in mice whether repeated administration of N-cyanomethylmethamphetamine HCl (molar mass: 211.70 g/mol) induced sensitization to its central stimulant effect, and whether there were cross-sensitization from N-cyanomethylmethamphetamine HCl to methamphetamine HCl, and from methamphetamine HCl to N-cyanomethylmethamphetamine HCl. N-cyanomethylmethamphetamine HCl 14.2 and 47.2 mumol/kg subcutaneously dose-dependently accelerated ambulation of mice. Five administrations at 3 day intervals caused sensitization, the activity counts in the fifth administration being approximately 2.6 and 1.6 times, higher respectively, than those in the first administration. Furthermore, the mice repeatedly given 14.2 and 47.2 mumol/kg N-cyanomethylmethamphetamine HCl exhibited cross-sensitization to methamphetamine HCl (10.8 mumol/kg subcutaneously). Whereas 1.4 and 4.7 mumol/kg N-cyanomethylmethamphetamine HCl did not induce significant acceleration of the ambulation throughout the 5 repeated administrations, nor cross-sensitization to methamphetamine HCl. On the other hand, the 5 repeated administrations of methamphetamine HCl (10.8 mumol/kg) also caused sensitization to its ambulation-increasing effect, and the activity count in the fifth administration attained approximately 2.0 times higher than that in the first administration. The mice given methamphetamine HCl demonstrated cross-sensitization to 1.42-14.2 mumol/kg N-cyanomethylmethamphetamine HCl. Haloperidol (CAS code value: 52-86-8, molar mass: 375.88 g/mol; 0.027-0.80 mumol/kg subcutaneously) dose-dependently reduced the ambulation-increasing effects of N-cyanomethylmethamphetamine HCl and methamphetamine HCl in the drug-naive, and N-cyanomethylmethamphetamine HCl- and methamphetamine HCl-sensitized mice. These dose-effect relationships were similar between groups. The present results suggest that N-cyanomethylmethamphetamine HCl has a behavioural stimulant effect almost similar to that of methamphetamine HCl.