William H. Soine

Differentiation of 2,3-Methylenedioxyamphetamine from 3,4-Methylenedioxyamphetamine

The 2,3- and 3,4-methylenedioxyamphetamine isomers can be distinguished using the sulfuric acid color test, gas chromatography, infrared spectroscopy, mass spectrometry, and 13C nuclear magnetic resonance.

1-(2,3-methylenedioxyphenyl)-2-aminopropane (2,3-MDA): A preliminary investigation

Rats trained to discriminate saline from either (+)-amphetamine, (+/-)-DOM, or (+/-)-3,4-MDA in a two-lever drug discrimination paradigm were administered doses of a novel positional isomer of 3,4-MDA, i.e. 2,3-MDA. The novel isomer produced neither amphetamine-appropriate nor DOM-appropriate responding: the 3,4-MDA stimulus did, however, generalize to 2,3-MDA.

High-performance liquid chromatographic analysis of phenobarbital and phenobarbital metabolites in human urine.

A HPLC assay using UV detection and post-column alkalinization was developed to quantify possible urinary excretion products of phenobarbital in human urine. After filtration the urine was injected directly onto the HPLC column for analysis of phenobarbital, p-hydroxyphenobarbital, phenobarbital N-glucosides and phenobarbital N-glucuronides. The accuracy and precision of the assay were within +/- 15% and the limit of detection (LOD) was 1 microM, suitable for pharmacokinetic studies. Phenobarbital was administered orally to five male subjects and urine was collected for a period of 96-108 h. Phenobarbital, p-hydroxyphenobarbital, and phenobarbital N-glucosides were detected and quantified in the urine of all five subjects. The phenobarbital N-glucuronides were not detected in the urine. This assay provides a rapid method with improved selectivity to analyze urine for phenobarbital and its metabolites.

Phenobarbital N-glucosylation by human liver microsomes

SummaryGlucosylation of xenobiotics in mammals has been observed for a limited number of drugs. Generally, these glucoside conjugates are detected as urinary excretion products with limited information on their formation. An in vitro assay is described for measuring the formation of the phenobarbital N-glucoside diasteriomers ((5R)-PBG, (5S)-PBG) using human liver microsomes. Human livers (n=18) were screened for their ability to N-glucosylate PB. Cell viability, period of liver storage, prior drug exposure, serum bilirubin levels, age, sex and ethnicity did not appear to influence the specific activities associated with the formation of the PB N-glucosides. The average rate of formation for both PB N-glucoside was 1.42±1.04 (range 0.11–4.64) picomole/min/mg-protein with an (5S)-PBG/(5R)-PBG ratio of 6.75±1.34. The apparent kinetic constants, Km and Vmax, for PB N-glucosylation for eight of the livers ranged from 0.61–20.8 mM and 2.41–6.29 picomole/min/mg-protein, respectively. The apparent Vmax/Km ratio for PB exhibited a greater than 20 fold variation in the ability of the microsomes to form the PB N-glucosides. It would appear that the formation of these barbiturate N-glucoside conjugates in vitro are consistent with the amount of barbiturate N-glucosides formed and excreted in the urine in prior drug disposition studies.

Differentiation of Side Chain Positional Isomers of Amphetamine

The eleven side chain positional isomers of amphetamine can be distinguished using a combination of color tests, thin-layer chromatography, and mass spectrometry. The primary amines, 1-phenylpropylamine and β-methylphenethylamine, exhibited chromatographic behavior similar to amphetamine but were readily differentiated using mass spectrometry. The mass spectra of N-methylphenethylamine was very similar to amphetamine, but using color tests and chromatography it was readily differentiated from amphetamine.