Validated liquid chromatographic-electrospray ionization mass spectrometric assay for simultaneous determination of 3,4-methylenedioxymethamphetamine and its metabolites 3,4-methylenedioxyamphetamine, 3,4-dihydroxymethamphetamine, and 4-hydroxy-3-methoxymethamphetamine in squirrel monkey plasma.

3,4-Methylenedioxymethamphetamine (MDMA) is a recreational drug with neurotoxic potential. Pharmacokinetic data of MDMA and its metabolites may shed light on the mechanism of MDMA neurotoxicity. An LC-MS assay with electrospray ionization (ESI) is presented for quantifying MDMA and its metabolites 3,4-methylenedioxyamphetamine (MDA), 3,4-dihydroxymethamphetamine (HHMA), and 4-hydroxy-3-methoxymethamphetamine (HMMA) in squirrel monkey plasma. The method involved enzymatic conjugate cleavage and protein precipitation. Separation was achieved within 14min. The method was validated according to international guidelines with respect to selectivity, linearity, accuracy, precision, recovery, and matrix effect. The present method should prove useful for acquiring pharmacokinetic and toxicokinetic data in squirrel monkeys.

Simultaneous liquid chromatographic-electrospray ionization mass spectrometric quantification of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) and its metabolites 3,4-dihydroxymethamphetamine, 4-hydroxy-3-methoxymethamphetamine and 3,4-methylenedioxyamphetamine in squirrel monkey and human plasma after acidic conjugate cleavage.

3,4-Methylenedioxymethamphetamine (MDMA, Ecstasy) is a psychoactive drug with abuse liability and neurotoxic potential. Specimen preparation of a recently presented LC-MS assay with electrospray ionization for quantifying MDMA and its main metabolites in squirrel monkey plasma was modified to include acidic hydrolysis to obtain total 3,4-dihydroxymethamphetamine and 4-hydroxy-3-methoxy-methamphetamine. Method re-validation for squirrel monkey plasma and full validation for human plasma showed selectivity for all analytes. Recoveries were > or = 71.0%. Changed specimen preparation or matrix did not affect accuracy or precision. No instability was observed after repeated freezing or in processed samples. Plasma MDMA and metabolites quantification, derived pharmacokinetic and toxicokinetic data and neurotoxicity research will benefit from this validated method.

Gas chromatographic-mass spectrometric identification of epinine in rat superior cervical ganglia and formation in vivo.

Epinine was identified in rat superior cervical ganglia by a gas chromatographic-mass spectrometric method. The deuterated methyl group of i.v. administered labeled methionine was incorporated into epinine at a slow rate, although epinephrine-CD3 was rapidly formed. These results indicate that epinine found in the ganglia is not a precursor of epinephrine.

[Fluorimetric assay of 3-o-methyldopamine and 4-0-methyldopamine in rat urine and o-methylation of dopamine]. / Dosage fluorimétrique de la 3-O-méthyldopamine et de la 4-O-méthyldopamine dans l'urine de rat et O-méthylation de la dopamine

A new method for the isolation and determination of 3-O-methyldopamine (3 MD) and 4-O-methyldopamine (4 MD) in the urine of Rat has been described. The administration of L-dopa enabled us to detect 4 MD in the urine with a molar ratio 4 MD/3 MD = 0.07. This ratio decreased with the simultaneous treatment of S-adenosylmethionine (SAM). This result might explain the therapeutic L-dopa+SAM in the treatment of parkinsonism, 4 MD being neurotoxic. The low level of 4 MD compared with the level of isovanillic acid, found by other authors, seems to indicate that the 4-O-methylation pathway takes place via dihydroxyphenylacetic acid.

Reverse-phase chromatography of polar biological substances: separation of catechol compounds by high-performance liquid chromatography.

Catecholamines and their metabolites have been separated isocratically by reverse-phase chromatography with aqueous (no organic solvent admixed) eluents. Unlike ion-exchange or ion-pair chromatography, mixtures of both acidic and basic substances can be separated in a single chromatographic run, because the retention is governed by hydrophobic interactions between the nonpolar moiety of the solute molecules and the octadecyl-silica stationary phase. The relative retention values strongly depend on the pH of the eluent, which governs the degree of dissociation of ionogenic solutes. The reproducibility of the results and the stability and efficiency of the chromatographic systems make this approach particularly attractive for use in clinical analysis.