Improved Methods for Quantitative Determination of Methadone

Comparison of isolation procedures for the gas chromatographic determination of methadone in human liver

“…Similar methadone recoveries of about 80% have been reported for the alkaline digestion procedures (12,13) and the direct extraction procedure (14). Furthermore, the acid digestion method gave identical recoveries to the direct extraction method (11).…”

“…A very minor peak (peak height less than 2% that of methadone) was detected in the gas chromatograms of both the acid and alkaline digest extracts at about R methadone of 1.50 on 3% OV-17 and 1.48 on 2.5% OV-1. This peak was tentatively identified as the primary methadone metabolite l,5-dimethyl-3,3-diphenyl-2-ethylidenepyrrolidine which has been detected in biological specimens (13,14). The low level present did not permit positive identification of the compound.…”

“…The methadone level (0.8 pg/g) in the liver is higher than the levels found in two of the four cases reported by Nelson and Selkirk (11) which, as in this case, did not involve other drugs but is low in comparison with other studies (14,16). LITERATURE CITED For the determination of methadone, gas chromatography was preferred to the oxidation procedures of Wallace et al (12,13). The latter methods involve the conversion of methadone to benzophenone, which is estimated spectrophotometrically, and suffer from a loss of specificity as several other drugs will produce benzophenone under the same conditions.…”

“…detection of methadone in biological fluids (6-10), but comparatively little information is available for comparable studies on tissues (11)(12)(13)(14).…”

“…The alkaline digestion and the direct extraction methods gave similar recoveries, 78.7% (12) and 87% (14), respectively, from spiked samples. An improved analytical procedure utilizing the alkaline digestion gave a recovery of 85% (13).…”