SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

A84
SIMULTANEOUS DETERMINATION OF BUPRENORPHINE. NORBUPRENORPHINE.
BUPRENORPHINE-3-GLUCURONIDE AND NORBUPRENORPHINE-3-GLUCURONIDE IN
HUMAN PLASMA AND URINE BY LIQUID CHROMATOGRAPHY ELECTROSPRA Y
IONIZA TION TANDEM MASS SPECTROMETRY: APPLICATION TO HUMAN
PHARMACOKINETICS
Wei Huang" \ Elinore F.McCance-Katr and David E. Moodyl, lCenter for Human Toxicology,
Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112 and 2Division
of Addiction Psychiatry, Virginia Commonwealth University, Richmond, VA 23298
Our previously described method for buprenorphine (BUP), norbuprenorphine (NBUP), buprenorphine-3­
glucuronide (BUPG) and norbuprenorphine-3-glucuronide (NBUPG) (SOFT 2003) has undergone a slight
modification prior to full validation and use in a pharmacokinetics study. The monitored ions for NBUP
and its internal standard d 3 -NBUP were changed from 101 (product ion) to 414 (parent ion) and 101 to 417,
respectively. This provided stronger signals and a resultant lower limit of quantitation (LLOQ) of 0.1
nglmL for NBUP.
A full validation using human plasma with a cross-validation to human urine was conducted. The LLOQ
was 0.1 ng/mL for all analytes in human plasma. For the urine samples, the LLOQ was 0.5 nglmL for
BUP, BUPG and NBUPG and 2.5 ng/mL for NBUP due to interference in some urine samples. The intraassay
precision, as coefficient of variation (%CV), at 0.1, 0.25, 25 and 40 ng/mL in plasma did not exceed
17.5% at the LLOQ or 12.5% at all other concentrations for all analytes; in urine, the %CV did not exceed
17.4% at the LLOQ or 13.3% at all other concentrations for all analytes. The intra-assay accuracy, as %
deviation from target, in plasma did not exceed 12.3% at all concentrations for the four compounds; in
urine the % deviation did not exceed 14% at all concentrations. The interassay precision and accuracy was
determined at 0.25,25 and 40 ng/mL; %CV did not exceed 7.0% and the % deviation did not exceed 5.6%
for the four analytes. The method has now been used to determine the pharmacokinetics of the four
analytes in plasma and urine collected from five patients who had been maintained on a daily sublingual
does of 16 mg buprenorphine for at least 21 days. Plasma was prepared from blood collected for 13 time
points from just prior to 24 hours after the daily dose and urine collected for the same 24-hour period. The
results were as follows:
Pharmacokinetic parameter BUP NBUP BUPG NBUPG
Plasma
Cmax (ng)(mL)"1 4.47::1: 0.54 6.36::1: 1.84 7.19::1:3.27 21.5::1: 4.2
Tmax(h) 0.85::1: 0.42 1.00::1: 0.47 0.80::1: 0041 1.80::1: 0.27
AUC (ng)(mL)"I(h) 32.1::1: 3.8 87.6::1: 24.6 25.5::1: 7.9 316::1:172
24-hour Urine
Concentration (ng)(mLr l 0.94::1: 0.67 112::1: 58 94.9::1: 27.0 463::1: 153
Amount (% daily dose) 0.014::1: 0.011 1.89::1: 1.10 1.01::1: 0.42 5.43 ::1:2.46
Renal Clearance (mL)(min)"1 1.09::1: 0.83 48.7 ::1:23.9 148::1: 43 59.1::1: 6.8
The current method has been shown to be accurate and precise with sufficient sensitivity to monitor all four
analytes in human plasma and urine samples. The pharmacokinetic data, for the first time, show the
magnitude of involvement ofNBUPG in the clearance of buprenorphine.
Supported by NIDA grants ROI DA 10100, ROI DA 13004, and K02 DA 00478
Key words: Buprenorphine, Glucuronide metabolites, Pharmacokinetics
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