Extraction method and thin-layer chromatographic system for the determination of alpha-l-acetylmethadol and...

An extraction method and thin-layer chromatographic (TLC) system for the determination of alpha-l-acetylmethadol and its known metabolites (methadol, noracetylmethadol, dinoracetylmethadol, normethadol, 6-acetamide-4,4-diphenyl-3-heptanol, and N-methyl-6-acetamido-4,4-diphenyl-3-heptanol) are described. The parent drug and metabolites are extracted from biological fluids with ethyl acetate and separated by TLC using silica gel plates and a developing system of ethyl acetate-methanol-water-ammonia (85:10:1:1). This system may be used to quantitatively determine levels of radiolabeled drug and metabolites by scraping the TLC plates into 3-mm zonal fractions and measuring the amount of radioactivity by scintillation counting. A representative radiochromatogram obtained from an extract of monkey urine is shown.