Interaction between phencyclidine and its pyrolysis product, 1-phenylcyclohexene

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.

Metabolic aspects of the toxicology of mixtures of parathion, toxaphene and/or 2,4-D in mice

The effects of mixtures of parathion (PA;5 mg kg-1), toxaphene (TOX; 50 mg kg-1)and/or 2,4-dichlorophenoxyacetic acid (2,4-D; 50 mg kg-1) on the hepatic mixed-function oxygenase (MFO) system were studied in ICR male mice (21-24 g) by oral intubation daily for 7 days. In general, TOX and TOX-containing mixtures were found to induce the metabolism of amidopyrine (21-52%), aniline (58-72%), phenacetin (239-307%), pentobarbital (104-148%) and benzo[a]pyrene (143-304%) in the 9000 g liver supernatants and to increase the hepatic cytochrome P-450 contents (57-80%). Furthermore, the TOX pretreatment was effective in enhancing the biotransformation of PA or paraoxon (PO) in the supernatants. This enhancement was not altered significantly by 5 mM EDTA. Although TOX increased the aliesterase activity in the serum and liver homogenates and supernatants by 31-158%, the activity of paraoxonase was not affected in these preparations. The TOX-induced increase in the metabolism of PA or PO was, at least in part, associated with the MFO system, and paraoxonase did not have significant involvement in the increase. These findings suggest that the toxicity of the PA + TOX mixture would be lower than that of PA, as TOX has the ability to increase the biotransformation of PA, as well as of PO, and the levels of aliesterase, thereby providing a pool of noncritical enzymes for the binding of PO. Because of these properties of TOX, it is anticipated that the toxicity of the PA + TOX + 2,4-D mixture also would be lower than that of PA.