ISSN: 0022-1198
CODEN: JFSCA
Page Count: 6

Metabolic Production of Amphetamine Following Administration of Clobenzorex
Cody, JT
Clinical Research Squadron, Wilford Hall Medical Center, Texas

Valtier, S
Clinical Research Squadron, Wilford Hall Medical Center, Texas

(Received 21 April 1998; accepted 25 June 1998)

Abstract

Many of the anorectic drugs that are metabolized to amphetamine and/or methamphetamine pose significant concerns in the interpretation of amphetamine-positive drug testing results. One of these drugs—clobenzorex—has been shown to produce amphetamine. Thirty milligrams of clobenzorex hydrochloride, in the form of a single Asenlix capsule (Roussel, Mexico), were administered orally to five human volunteers with no history of amphetamine, methamphetamine or clobenzorex use. Following administration, urine samples (total void volume) were collected ad lib for seven days and pH, specific gravity and creatinine values were determined. To determine the excretion profile of amphetamine and parent drug, samples were extracted, derivatized, and analyzed by gas chromatography/mass spectrometry (GC/MS) using a standard amphetamine procedure with additional monitoring of ions at m/z 91, 118, 125 and 364 for the detection of clobenzorex. Peak concentrations of amphetamine were detected at 4 to 19 h postdose and ranged from approximately 715 to 2474 ng/mL amphetamine. Amphetamine could be detected (>5 ng/mL) in the urine in one subject for up to 116 h postdose. GC/MS was also used to determine the enantiomeric composition of the metabolite, amphetamine. This analysis revealed the metabolically derived amphetamine was only the d-enantiomer. This differs from previous literature which indicates clobenzorex is the racemic N-orthochlorobenzyl derivative of amphetamine.

Keywords:
forensic science, clobenzorex, GC/MS, enantiomer analysis, amphetamine, metabolism, anorectic drug, precursor drug, Asenlix

Paper ID: JFS14406J
DOI: 10.1520/JFS14406J
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