HAIR ANALYSIS FOR BUPRENORPHINE AND ITS DEALKYLATED METABOLITE BY RIAAND CONFIRMATION BY LC ECD/

Hair samples were obtained from 14 subjects admitted 2 or 3 months pre viously to a detoxification center. All reported an history of intrave nous heroin abuse. After decontamination by two dichloromethane washes , about 50 mg hair were pulverized in a ball mill and incubated at 56 degrees C overnight in 1 mt 0.1 HCl. After neutralization, buprenorphi ne analyzed by RIA was in the range of 0.01 to 0.47 ng/mg. To confirm buprenorphine, liquid chromatography was used. After neutralization, d rugs were extracted with toluene at pH 8.5 during a 3-step extraction procedure. A portion of the reconstituted residue was injected into a Lichrosorb CN column, with a mobile phase of phosphate buffer (pH 4.0) -acetonitrile-1-heptane sulfonic acid-butylamine (85:17:2:0.01, v/v). Detection was achieved by coulometry, and the potential of the electro des was 0.15 and 0.50 V, respectively. Linear calibration curves were obtained from 0.02 to 2.0 ng/mg with a correlation coefficient r > 0.9 9 for both drugs. The detection limit for the major metabolite was abo ut 0.01 ng/mg and 0.02 ng/mg for buprenorphine, using a 50 mg hair sam ple. Recovery (at 0.2 ng/mg) was 54 and 62% for norbuprenorphine and b uprenorphine, respectively. Drugs concentrations in hair were in the r ange 0.02-0.59 and not detected-0.15 ng/mg for buprenorphine and norbu prenorphine, respectively. Results suggest that a dose-reponse relatio nship exists between the concentration of buprenorphine in hair and th e administered dose.