Munehiro Katagi

Metabolism of the recently encountered designer drug, methylone, in humans and rats

The urinary metabolites of methylone in humans and rats were investigated by analysing urine specimens from its abuser and after administrating to rats with gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-electrospray ionization mass spectrometry (LC-ESI MS), using authentic standards. The time-course excretion profiles of methylone and its three metabolites in rats were further investigated after a single intraperitoneal dosing of 5 mg kg−1 methylone hydrochloride. Two major metabolic pathways were revealed for both humans and rats as follows: (1) side-chain degradation by N-demethylation to the corresponding primary amine methylenedioxycathinone (MDC), partly conjugated; and (2) demethylenation followed by O-methylation of either a 3- or 4-OH group on the benzene ring to produce 4-hydroxy-3-methoxymethcathinone (HMMC) or 3-hydroxy-4-methoxymethcathinone (3-OH-4-MeO-MC), respectively, mostly conjugated. Of these metabolites, HMMC was the most abundant in humans and rats. The cumulative amount of urinary HMMC excreted within the first 48 h in rats was approximately 26% of the dose, and the amount of the parent methylone was not more than 3%. These results demonstrate that the analysis of HMMC will be indispensable for proof of the use of methylone in forensic urinalysis.

Determination of the metabolites of the new designer drugs bk-MBDB and bk-MDEA in human urine

This is the first report on identifying the specific metabolites of the new designer drugs 2-methylamino-1-(3,4-methylenedioxyphenyl)butan-1-one (bk-MBDB) and 2-ethylamino-1-(3,4-methylenedioxyphenyl)propan-1-one (bk-MDEA) in human urine using synthesized standards. Based on GC/MS and LC/MS, we identified N-dealkylation, demethylenation followed by O-methylation, and beta-ketone reduction as their major metabolic pathways. The quantitative analyses by LC/MS revealed that both demethylenation followed by O-methylation and beta-ketone reduction were superior to N-dealkylation and that both bk-MBDB and bk-MDEA were mainly metabolized into their corresponding 4-hydroxy-3-methoxy metabolites (4-OH-3MeO metabolites). After hydrolysis, the concentrations of 4-OH-3MeO metabolites and 3-hydroxy-4-methoxy metabolites of both bk-MBDB and bk-MDEA dramatically increased, suggesting that the metabolites mainly exist as their conjugates.

Determination of Methamphetamine and Its Related Compounds Using Fourier Transform Raman Spectroscopy

Fourier transform Raman spectroscopy (FT-Raman) is investigated as a simple and rapid method for the determination of the abused drug methamphetamine and its related compounds. Compounds can be reliably identified by using measurements made nondestructively and without the need for any sample preparation in around 1 min. The Raman spectrum of methamphetamine hydrochloride (MA) shows clear differences in spectra from a range of its related compounds such as amphetamine sulfate and ephedrine hydrochloride. These differences are adequate for spectral differentiation of the compounds. With the use of the FT-Raman technique, MA is also reliably identifiable to a detection limit of 1% (w/w) diluted in sodium chloride or water. FT-Raman spectra of MA were recorded through plastic packaging (polyethylene or polypropylene bags) typical of that used either by criminals for transportation or by law enforcement for containing and sealing evidence. Measurements could be made directly without removing the drug from the bag; excellent-quality spectra could be obtained with very little perturbation by the plastic bag.

Recently abused β-keto derivatives of 3,4-methylenedioxyphenylalkylamines: a review of their metabolisms and toxicological analysis

Abstractβ-Keto derivatives of 3,4-methylenedioxyphenylalkylamines (bk-MDPAs), especially 2-methylamino-1-(3,4-methylenedioxyphenyl)propan-1-one (methylone), 2-methylamino-1-(3,4-methylenedioxyphenyl)butan-1-one (bk-MBDB), and 2-ethylamino-1-(3,4-methylenedioxyphenyl)propan-1-one (bk-MDEA), are abused as substitutes for 3,4-methylenedioxyphenylalkylamines in some countries, causing increased social problems. With the widespread abuse of bk-MDPAs, the analysis of bk-MDPAs and their metabolites in human specimens is quite important in forensic and clinical toxicology. In this review, the metabolisms of bk-MDPAs and simultaneous analytical methods for bk-MDPAs and their metabolites by gas chromatography–mass spectrometry, liquid chromatography–mass spectrometry, and liquid chromatography–tandem mass spectrometry are presented.

On-line solid-phase extraction liquid chromatography-continuous flow frit fast atom bombardment mass spectrometric and tandem mass spectrometric determination of hydrolysis products of nerve agents alkyl methylphosphonic acids by p-bromophenacyl derivatization

For proof of the presence of chemical warfare agents sarin, soman and VX, a rapid, accurate and sensitive method which allows us to determine their hydrolysis products ethyl methylphosphonic acid, isopropyl methylphosphonic acid and pinacolyl methyl phosphonic acid was explored by using continuous flow frit fast atom bombardment (FAB) LC-MS and LC-MS-MS. After derivatization of analytes with p-bromophenacyl bromide, LC-MS-MS analyses for screening were performed by a flow injection method. The three alkyl methylphosphonic acids (AMPAs) were eluted within 5 min, and the detection limits for the three AMPAs ranged from 1 to 5 ng/ml. For confirmation of the screening results, LC-MS-MS analysis with chromatographic separation was conducted by using a narrow bore column. The three AMPAs were all eluted with excellent separation within 25 min, and the detection limits ranged from 1 to 20 ng/ml. Quantitative measurement was performed by LC-MS in selected ion monitoring (SIM) mode with chromatographic separation. Linear calibration curves were obtained for the three AMPAs and the detection limits ranged from 0.5 to 3 ng/ml. The relative standard deviation for peak area ranged from 3.4 to 6.0% at 50 ng/ml for the three AMPAs.

Influences of methamphetamine-induced acute intoxication on urinary and plasma metabolic profiles in the rat.

Methamphetamine (MA) is an illicit psychostimulant, and its abuse has become an international public health problem. MA intoxication can cause life-threatening hyperthermia, renal and liver failure, cardiac arrhythmias, and neurological damage. To investigate the relationship between the underlying mechanism of such intoxication and metabolic networks, mass spectrometry-based metabolomics experiments were performed on Sprague-Dawley rats treated with MA at 10mgkg(-1)h(-1) for 4h. Using a combination of gas chromatography-time-of-flight mass spectrometry and capillary electrophoresis-tandem mass spectrometry, global and targeted analyses were performed on biological samples collected during 0-24 and 72-96h (for urine), and at 24 and 96h (for plasma) after the last drug administration. Body temperature and plasma biochemical parameters were also measured to detect abnormal reactions in neuronal and other several tissues. 5-Oxoproline, saccharic acid, uracil, 3-hydroxybutyrate (3-HB), adipic acid, glucose, glucose 6-phosphate, fructose 1,6-bisphosphate, and tricarboxylic acid (TCA) cycle intermediates, such as fumarate, were proposed as potential biomarkers related to MA-induced intoxications. In particular, the observation of decreased TCA cycle intermediates and 3-HB and increased glucose suggested that high doses of MA inhibit biogenic energy production by glycolysis, oxidative phosphorylation via the TCA cycle, and the beta-oxidation of fatty acids. These results may provide not only a clue to clarify the underlying mechanism of diverse intoxication effects, but also biological fluid-based diagnostic and forensic methods with which to objectively demonstrate intoxication without directly determining the drug.

Metabolism of the newly encountered designer drug α -pyrrolidinovalerophenone in humans: identification and quantitation of urinary metabolites

Urinary metabolites of α-pyrrolidinovalerophenone (α-PVP) in humans were investigated by analyzing urine specimens obtained from abusers. Unambiguous identification and accurate quantification of major metabolites were realized using gas chromatography–mass spectrometry and liquid chromatography-tandem mass spectrometry with newly synthesized authentic standards. Two major metabolic pathways were revealed: (1) the reduction of the β-keto moiety to 1-phenyl-2-(pyrrolidin-1-yl)pentan-1-ol (OH-α-PVP, diastereomers) partly followed by conjugation to its glucuronide, and (2) the oxidation at the 2″-position of the pyrrolidine ring to α-(2″-oxo-pyrrolidino)valerophenone (2″-oxo-α-PVP) via the putative intermediate α-(2″-hydroxypyrrolidino)valerophenone (2″-OH-α-PVP). Of the metabolites retaining the structural characteristics of the parent drug, OH-α-PVP was most abundant in most of the specimens examined.

Urinary excretion of the main metabolites of 3,4-methylenedioxymethamphetamine (MDMA), including the sulfate and glucuronide of 4-hydroxy-3-methoxymethamphetamine (HMMA), in humans and rats

The urinary concentrations of the main metabolites of 3,4-methylenedioxymethamphetamine (MDMA; Ecstasy), specifically 4-hydroxy-3-methoxymethamphetamine sulfate (HMMA-Sul) and 4-hydroxy-3-methoxymethamphetamine glucuronide (HMMA-Glu), have been directly measured in both MDMA users and rats by an established liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) procedure. The concentrations of these conjugates in urine from MDMA users (n = 25) ranged from 6.5 to 202 µM (from 1.8 to 55.6 µg ml−1) for HMMA-Sul and from 1.3 to 87.0 µM (from 0.5 to 32.3 µg ml−1) for HMMA-Glu, and the ratio of HMMA-Sul to HMMA-Glu ranged from 1.6 to 9.9 (3.1 ± 1.8). These results demonstrate that the sulfation is quantitatively more significant than the glucuronidation for HMMA in humans. In rats, in contrast, almost all the conjugated HMMA (>99%) was excreted as the glucuronide. These findings indicate that hydrolysis should be carefully made in urine analysis by gas chromatography (GC) or gas chromatography-mass spectrometry (GC-MS) by using either an acid or an enzyme possessing both sulfatase and β-glucuronidase activities. It is concluded that a considerable interspecies variation exists in the conjugation of HMMA between humans and rats.

Recently abused synthetic cathinones, α-pyrrolidinophenone derivatives: a review of their pharmacology, acute toxicity, and metabolism

The aim of this review is to present the chemical aspects, pharmacology, acute toxicities, and metabolisms of α-pyrrolidinophenone derivatives, a new group of synthetic cathinones. Compared to other synthetic cathinones, α-pyrrolidinophenone derivatives have high lipophilicity due to the pyrrolidine ring substitution at the nitrogen atom, resulting in higher blood–brain barrier permeability. To date, some acute intoxication and fatal cases involving α-pyrrolidinophenone derivatives have been reported, and the symptoms induced by their high dosages are due to central nervous system and cardiovascular toxicities. Based on the previous metabolism studies, reduction of the β-ketone moiety to the corresponding alcohol metabolites and oxidation to the 2′′-oxo metabolites are the main metabolic pathways observed among α-pyrrolidinophenone derivatives. In addition to such pathways, specific metabolic pathways like hydroxylation followed by oxidation of the 4′-methyl group, O-demethylation of the 4′-methoxyl group, and demethylenation followed by O-methylation of the 3′,4′-methylenedioxy group can be observed for the corresponding ring-substituted compounds.

Urinary excretion and metabolism of the newly encountered designer drug 3,4-dimethylmethcathinone in humans

Cathinone-derived designer drugs have recently grown to be popular as drugs of abuse. 3,4-Dimethylmethcathinone (DMMC) has recently been abused as one of the alternatives to controlled cathinones. In the present study, DMMC and its major metabolites, 3,4-dimethylcathinone (DMC), 1-(3,4-dimethylphenyl)-2-methylaminopropan-1-ol (β-OH-DMMC, diastereomers), and 2-amino-1-(3,4-dimethylphenyl)propan-1-ol (β-OH-DMC, diastereomers), have been identified and quantified in a DMMC user’s urine by gas chromatography–mass spectrometry and liquid chromatography–tandem mass spectrometry using newly synthesized authentic standards. Other putative metabolites including oxidative metabolites of the xylyl group and conjugated metabolites have also been detected in urine. The identified and putative phase I metabolites indicated that the metabolic pathways of DMMC include its reduction of the ketone group to the corresponding alcohols, N-demethylation to the primary amine, oxidation of the xylyl group to the corresponding alcohol and carboxylate forms, and combination of these steps. Concentrations of the identified metabolites were found to increase slightly after enzymatic hydrolysis, suggesting that these compounds are partially metabolized to the respective conjugates.