A method of identifying narcotic analgesics in human urine after therapeutic doses

Abstract

Alkaloids were separated from urine in 15 min with an Amberlite XAD-2 resin column, and the methanol eluate was chromatographed on 2 thin-layer silica gel glass microfiber sheets to establish a pattern of spots for each narcotic analgesic and its metabolites. Ten milliliters of urine applied to a column of Amberlite XAD-2 resin (1 × 6 cm) was flushed with an equal volume of water. The adsorbed drug and its metabolites were eluted with methanol nonselectively into the same fraction as some highly colored urinary pigments. The latter served as a guide to collect the alkaloid-containing fraction. Sixty microliters of the fraction were spotted on 2 Gelman SG sheets; these chromatograms were developed in 2 solvent systems: I ( n-butanol-acetic acid-water, 35:3:10) and IV (CHCl 3 saturated with ammonium hydroxide). The chromatograms were sprayed with iodoplatinate reagent, and unknowns were identified by matching their pattern of spots (drug and metabolites) with the pattern for urine standards run on the same chromatograms. From patients receiving no medication and others receiving therapeutic doses of narcotic analgesics 140 coded urine samples were collected. These unknowns were not decoded until after completion of the analysis. Six (out of the 7) control samples from untreated patients were correctly demonstrated to contain no alkaloids. The remaining 134 of the 140 samples were shown to be positive to iodoplatinate. Of these 134, 88 were identified correctly to be 27 meperidine, 29 codeine, 2 morphine, 1 levorphanol, 27 pentazocine, and 2 dihydromorphinone samples. In the remainder, 13 could not be assigned to a specific narcotic analgesic, and 33 were misidentified. Both these types of errors arose largely from paucity in number of alkaloid spots for matching with the urine standards. In spite of these shortcomings, the ease, speed, high sensitivity for detection and possibility for differential identification of narcotic analgesics make this method highly practical.