The Urine Metabolic Enantiomeric Differences On Famprofazone Ingester And Methamphetamine Abuser

Abstract

Famprofazone is an antipyretic and analgesic that also has some slight sympathomimetic properties. It is a component of the multi-ingredient medication used for pain relief. This drug has been demonstrated to be metabolized to methamphetamine (MA) and amphetamine (AM) following administration and has been shown to produce a positive urinary test result. PURPOSE: To distinguish the differences of enantiomeric composition of MA and AM in urine following famprofazone administration or MA abuser. METHODS: Six healthy volunteers, with a mean age (±standard deviation, SD) of 25.2 ± 1.9 yrs, weight of 79.0 ± 14.1 kg, height of 174.5 ± 7.7 cm, participated in the experiment. One Gewolen tablet (25 mg of famprofazone) was administered orally to the subjects. After administration, urine samples were collected in the intervals of 0-1, 1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, 9-12, 12-15, 15-22, 22-28, 28-34, 34-40, 40-48, and 48-60 hrs. The concentrations of MA and AM for all urine samples were analyzed by gas chromatography-mass spectrometry (GC-MS). In addition, 12 urine samples from MA abuser which had been confirmed to MA positive testing result were collected. All urine samples were derivatized by N-trifluoroacetyl-l-prolyl chloride (l -TPC) and analyzed the enantiomers of the MA metabolites by GC-MS. RESULTS: Thirty four percent of the urine samples from famprofazone ingester showed MA positive (the concentrations of AM and MA higher than 100 and 500 ng/mL). The d-enantiomers of AM and MA in the urine of famprofazone ingester were 43.8± 3.0% and 28.5± 2.5%. However, the d-enantiomers of AM and MA in the urine of AM abusers were 98.6±2.1% and 97.5±1.7%. CONCLUSIONS: The enantiomers of urinary amphetamines metabolites from MA abuser urine differ from famprofazone ingester. Extra analysis of enantiomers can help the laboratory to avoid the interpretation of typical laboratory results of MA positive drug tests. Supported by NSC Grant 94-2413-H-252-003.