In vitro stability and metabolism of salvinorin A in rat plasma

Salvinorin A is the main active psychoactive ingredient in Salvia divinorum, a Mexican plant that has been widely available as a hallucinogen in recent years. The aims of this study were to investigate the stability of salvinorin A in rat plasma, esterases responsible for its degradation, and estimation of the degradation products. The apparent first-order rate constants of salvinorin A at 37 degrees C, 25 degrees C, and 4 degrees C were 3.8 x 10(-1), 1.1 x 10(-1), and < 6.0 x 10(-3) h(-1), respectively. Salvinorin A degradation was markedly inhibited by the addition of sodium fluoride, an esterase inhibitor. Moreover, phenylmethylsulfonyl fluoride (serine esterase inhibitor) and bis-p-nitrophenylphosphate (carboxylesterase inhibitor) also inhibited salvinorin A degradation. In contrast, little or no suppression of the degradation was seen with 5,5'-dithiobis-2-nitrobenzoic acid (arylesterase inhibitor),ethopropazine (butyrylcholinesterase inhibitor), and BW284c51 (acetylcholineseterase inhibitor). These findings indicated that carboxylesterase was mainly involved in the salvinorin A hydrolysis in rat plasma.4. The degradation products of salvinorin A estimated by liquid chromatography-mass spectrometry included the deacetylated form (salvinorin B) and the lactone-ring-open forms of salvinorin A and salvinorin B. This lactone-ring-opening reactions were involved in calcium-dependent lactonase.

In vivometabolism of 2,5-dimethoxy-4-propylthiophenethylamine in rat

The in vivo metabolism of 2,5-dimethoxy-4-propylthiophenethylamine (2C-T-7), a ring-substituted psychoactive phenethylamine, was studied in rat. Male Wistar rats were administered 10 mg/kg 2C-T-7 hydrochloride orally, and 24-h urine fractions were collected. After enzymatic hydrolysis of the urine sample, the metabolites were extracted by liquid-liquid extraction and analyzed by liquid chromatography/mass spectrometry. 2C-T-7-sulfoxide, N-acetyl-2C-T-7-sulfoxide, N-acetyl-2,5-dimethoxy-4-methylthiophenethylamine-sulfoxide, N-acetyl-2,5-dimethoxy-4-(2-hydroxypropylthio)phenethylamine-sulfoxide, and N-acetyl-2,5-dimethoxy-4-(2-hydroxypropylthio)phenethylamine-sulfone were detected as the primary metabolites of 2C-T-7. These findings suggest that sulfoxidation, sulfone formation, hydroxylation of the propyl side chain at the beta-position, and S-depropylation followed by methylation of thiol were the major metabolic pathways of 2C-T-7 in rat.

A study of the metabolism of methamphetamine and 4-bromo-2,5-dimethoxyphenethylamine (2C-B) in isolated rat hepatocytes

The metabolism of methamphetamine (MA) and 4-bromo-2,5-dimethoxyphenethylamine (2C-B) in freshly isolated rat hepatocytes was investigated, and compared with in vivo results. A suspended hepatocyte culture, established from male Wistar rats using a collagenase perfusion technique, was incubated in the presence of MA or 2C-B. After enzymatic hydrolysis of the conjugated forms, the metabolites were extracted by liquid-liquid partition and analyzed by gas chromatography/mass spectrometry (GC/MS). Amphetamine, p-hydroxymethamphetamine and p-hydroxyamphetamine were detected in the culture fluids of the rat hepatocytes inoculated with MA. The alcohol derivative, carboxylic acid derivative, 2-O-desmethyl-2C-B, 2-O-desmethyl-N-acetyl-2C-B and 5-O-desmethyl-N-acetyl-2C-B were detected in the case of 2C-B. The major metabolite of MA in rat hepatocytes was p-hydroxymethamphetamine. This is in good agreement with the urinary excretion profile for rats that were fed MA. 2-O-Desmethyl-2C-B and the carboxylic acid derivative were the major recovered metabolites of 2C-B in the rat hepatocyte culture, a slight deviation from the in vivo findings, in which 5-O-desmethyl-N-acetyl-2C-B was found to be the main component. Metabolites with a hydroxy group were largely present in their conjugated forms in the culture fluids, except for 2-O-desmethyl-2C-B. Taking these results into consideration, a primary hepatocyte culture system has the potential to provide a quick and handy method for estimating the in vivo metabolic fate of abused drugs.