Download Atypical Urinary Opiate Excretion Pattern*

Journal of Analytical Toxicology, Vol. 21, October 1997
Case Report I
Atypical Urinary Opiate Excretion Pattern*
Leon
R. Glass 1,2,~,Stephen T. IngaUsl, 3, Catherine L. Schilling 2, and Charles t. Hoppel 1,3
IResearch, 2pathology` and Laboratory Medicine Service, 113-B, Department of Veterans Affairs Medical Center, 10000
Brecksville Road, Brecksville, Ohio 44141 and 3Departments of Pharmacology and Medicine, Case Western Reserve University,
Cleveland, Ohio 44106
[ Abstract I
Heroin is rapidly metabolized in humans to 6-acetylmorphine
(6-AM), which is further metabolized to morphine and morphine
conjugates. Urinary 6-AM is the best diagnostic indicator of heroin
abuse. This metabolite however, is usually present in urine at less
than 3% of the concentration of urinary total morphine (MOR).
We present two case studies of 43-year-old, apparently identical,
male twins who displayed an atypical pattern of opiate
metabolism. The subjects had a history of opiate abuse, and they
are currently in a substance-abusetreatment program. Urine
specimenssubmitted by these subjectsfor periodic clinical urine
drug testing occasionally gave positive responsesfor opiates by
enzyme immunoassay.These samples were then submitted for
confirmation analysisusing a mixed-mode solid-phase extraction
sample preparation, trimethylsilyl derivatization, and capillary gas
chromatography--electron impact-massspectrometry confirmation
analysis. These specimens contained as much as 2000 ng/mL of
6-AM with lessthan 350 ng/mL of MOR, which yielded
6-AM/MOR ratios as large as 1100%. Additional urine samples
from these subjectsthat screened negative for opiates were
also tested for the presence of 6-AM. Clinically significant
concentrations of 6-AM were found in some of these samples.
Introduction
Illicit opiate use remains a major problem in North American society. Urine drug testing provides a tool for detecting
users and for monitoring the compliance of subjects in recovery programs. The complex metabolic pathways of codeine,
heroin (diacetylmorphine), and morphine complicate the interpretation of test results.
Heroin is rapidly degraded to 6-acetylmorphine (6-AM) by
both chemical and enzymatic processes. Heroin is labile in
aqueous solutions, and deacylation is accelerated in biological
fluids. In addition, there is extensive organ metabolism. The
plasma half-life of heroin has been estimated at 2-8 rain (1-3).
6-AM is more stable than heroin; it undergoes conversion to
* Data in this articlewere presentedin part at the annual meetingof the Societyof Forensic
Toxicologistsin Denver,Colorado,October 1996.
+Correspondenceshould be addressed to Leon R. Glass,Ph.D., PALMS113-B,VeteransAdministration MedicalCenter, 10000SrecksvilleRd., Brecksville,OH 44141,
morphine by enzymatic and nonenzymatic deacylationwith an
estimated plasma half-lifeof 10-40 rain (3,4). Morphine may be
further metabolized by demethylation to normorphine, and
both forms can be conjugated before excretion. Morphine and
its metabolites are excreted as free and glucuronide or sulfate
conjugates in bile, sweat, hair, and urine. Morphine
glucuronide is normally the major urinary metabolite of heroin
(5).
Codeine is metabolized by demethylation to morphine or
norcodeine and formation of conjugates. The rate of conversion
of codeine to morphine varies widely among individuals. Subjects with an accelerated codeine metabolism pathway can
produce urine specimens that are morphine positive with
codeine concentrations below the cutoff after a codeine dose
(6). Codeine is often present in the starting material for illicit
heroin (7). Additionally,metabolic conversion of morphine to
codeine has been reported (8). Thus, a user of heroin may
produce a specimen that is positive for both codeine and morphine. Dietary sources of opiates, such as poppy seeds, further complicate the differentiation of hard-core drug abusers
from the general population (1,9). These metabolic pathways
are shown in Figure 1.
Because of these complications, attention has lately been
focused on morphine precursors. The extreme labilityof heroin
limits its utility as a target analyte for routine abuse detection
(5). 6-AM is considered the best marker for heroin use because there is no natural source, it is not a codeine metabolite,
and it is comparativelystable relative to heroin (1,10,11). However, it is normally excreted in the first few hours following
heroin use, is present in trace concentrations, and has limited
chemical stability. The window of detection for 6-AMin urine
is less than 8-h postdose (12). The concentration of 6-AMwas
reported as approximately 1-3% of the concomitant total morphine (MOR) (13). The highest 6-AM/MORratio found in the
literature was less than 8% (14).
Experimental
Materials
Reagent-grade water was prepared by passage though a
Millipore purification system. The primary standards, codeine,
morphine, and 6-acetylmorphine, and the tri-deuterated
Reproduction (photocopying) of editorial content of this journal is prohibited without publisher's permission.
509
Journal of Analytical Toxicology, Vol. 21, October 1997
analogues were obtained from Radian (Austin, TX).
N,O-Bis(trimethylsilyl)trifluoroacetamide with 1% trimethylchlorosilane (BSTFA + TMCS) and derivatization-grade acetonitrile were purchased from Pierce Chemical (Rockford,IL).
Oxycodone,oxymorphone, hydrocodone, hydromorphone, levorphanol, dextromethorphan, pentazocine, meperidine,
normeperidine, dihydrocodeine, and 13-glucuronidase(Patella
vulgata) were purchased from Sigma Chemical (St. Louis,
MO). Mixed-modesolid-phase extraction (SPE) columns were
obtained from United Chemical Technologies (Horsham, PA)
and Radian. Sodium phosphate (dibasic), potassium phosphate
(monobasic), sodium acetate, methanol, and acetonitrile were
bought from J.T. Baker (Phillipsburg, NJ). All other solvents
and reagents were of analytical grade.
Standard solutions
The working calibrator for the codeine/morphine quantitative assay was prepared by fortifying drug-free urine to 300
ng/mL for each drug. Positive quality control solution was
prepared in a similar manner. Aliquots of these solutions were
stored at-70~ until needed, thawed before use, and stored at
4~ until the supply was exhausted. Deuterated internal standard solution was prepared in reagent-grade water.
Secondary standards for the 6-AM quantitative calibrator
and quality control were prepared in acetonitrile at 1.0 and 1.25
mg/mL, respectively. Secondary standard aliquots were stored
at -70~ until needed, thawed before use, and then stored at
-20~ until consumed. Working calibrator and positive quality
control were prepared on the day of assay by adding 100 p.L of
the secondary standards to separate 5-mL aliquots of drugfree urine to yield concentrations of 20-ng/mL calibrator, and
25-ng/mL positive quality control.
Mixtures of reference materials were prepared for use as
qualitative scan standards. Mixture I contained meperidine,
normeperidine, dextromethorphan, levorphanol, oxycodone,
oxymorphone, and hydrocodone. Mixture II contained penta-
Equipment
The sample preparation system included a vacuum manifold
(Supelco, Bellefonte, PA) for SPE and a Reacti-Vap III evaporator and heating block (Pierce) for eluant evaporation.
The chromatographic system consisted of a model 5890
series II gas chromatograph (GC) equipped with a model 7673
autoinjector coupled to a model 5971A quadrupole mass
selective detector, all of which were from Hewlett Packard
(Avondale,PA).
Extraction and derivatization procedure
Opiate assay. Deuterated internal standards were added to all
calibrator, quality control, and patient specimens. The scan
standards were prepared by adding 100-~L aliquots of Mixture
I and Mixture II to separate 4-mL aliquots of drug-free urine.
Two milliliters of [3-glucuronidase (5000 U/mL) in 1M acetate
buffer (pH 5) was added to each sample. Four milliliters of
300-ng/mL calibrator and 380-ng/mL positive quality control
were added to the assigned tubes. Drug-free urine was used as
the negative control. Four milliliters of patient urine, or an appropriate dilution in reagent-grade water, was added to the
respective tubes. The samples were mixed and allowed to hydrolyze overnight at 60~ The samples were cooled, adjusted
to pH 5.5-6.5 with 1N NaOH, centrifuged, and the supematant
layers were carried forward to SPE.
6-AM. Samples for 6-AM determination were prepared in
essentially the same manner as for opiate analysis but without
hydrolysis. Deuterated internal standard in acetonitrile was
added to all tubes and combined with 2 mL of 0.1M phosphate
buffer (pH 6). Working calibrator and positive control samples
were prepared at the time of assay by adding the secondary
standards to separate 5-mL aliquots of drug-free urine. Five
milliliters of patient urine, or a dilution of
the urine with reagent-grade water, was used.
The samples were mixed, adjusted to pH
5.5-6.5, centrifuged, and the supernatant
layers were carried forward to SPE.
F Cj
6-AM-I- MOR--- norMOR
F
Heroin
zocine, dihydrocodeine, codeine, hydromorphone, morphine,
and 6-monoacetylmorphine. Individualworking scan mixtures
were prepared on the day of assay by spiking drug-free urine.
Cj
F
Cj
C!D
V
Cj
norCOD
F
Cj
Figure 1. Human heroin, morphine, and codeine metabolism. Abbreviations: F, free drug; Cj, glucuronide- or sulfate-conjugated drug; Cj*, 6-acetylmorphine conjugation is mentioned in reference 14; 6-AM, 6-acetylmorphine; MOR, morphine; norMOR, normorphine; COD, codeine;
norCOD, norcodeine.
510
SPE
SPE columns were conditioned by the sequential passage of 3 mL of methanol, 3 mL
of reagent-grade water, and 1 mL of 0.1M
phosphate buffer (pH 6.0). The supernatant
layers from the samples were applied to the
SPE columns. The columns were washed
with 3 mL of reagent-grade water, 2 mL of
0.1M acetate buffer (pH 4.5), and 3 mL of
methanol. The columns were dried by application of approximately 20-in. Hg vacuum
for 10 min. The drugs were eluted with 3.0
mL of 4% concentrated ammonium hydroxide in ethyl acetate/isopropanol (84:12,
v/v) and collected in 12 x 75-ram glass tubes.
The solvent was removed under a stream of
Journal of Analytical Toxicology, Vol, 21, October 1997
dry, oil-free air in a 40~ heating block. The residue was reconstituted with 400 IJL of ethyl acetate/MeOH (70:30, v/v),
mixed, and transferred to an autosampler vial. The sample
was dried as described previously, reconstituted with 100 I~Lof
derivatization-grade acetonitrile, and capped. The trimethylsilyl derivatives were formed by reaction with 50 I~Lof
BSTFAplus TMCS for 45 rain at 70~ in a heating block. The
derivatized samples were transferred to autosampler microvials
and recapped for gas chromatographic-mass spectrometric
(GC-MS) analysis.
GC-MS conditions
and mass spectra obtained during same day analysis of scan
standard Mixtures I and II.
Results
l~vo 43-year-old, apparently identical, twin males were participants in a methadone-maintenance substance abuse treatment program at this Department of Veterans Affairs Medical
Center. These men had medical histories of opiate abuse. They
provided urine specimens for clinical drug abuse screening
twice each week as a condition of participation in the treatment program. In some specimens obtained from these men,
an unusual pattern of heroin metabolites was noted. Initially,
these isolated findings were viewed as artifacts, but several
more instances of this metabolite pattern in their urine specimens impelled further study. A detailed examination of urine
specimens obtained from these men during mid-1996 is described in this report.
Figure 2 displays a section of a scan-mode total ion chromatogram obtained during opiate analysis of urine from one of
the study subjects. The peak at retention time 13.26 rain corresponded with that of authentic 6-AMobtained from the scan
standards analyzed the same day. The ion spectrum from the
patient chromatograrn and spectrum of 6-AM-TMSare compared in Figure 3. Consequently a quantitative analytical
method for 6-AMwas developed and validated.
The recovery of 6-AM at 20 ng/mL was quantitative. The
quantitative assay for 6-AM was linear (r2 = 0.999) over the
concentration range 0.8--200 ng/mL with a slope of 0.95 and a
# intercept of 1.42. However,some of the qualifying ions for the
analyte and internal standard are common to both compounds.
Concentrated samples in which the qualifying ratios were not
within 20% were re-extracted using a greater dilution. The
usual limit of quantitation and detection in our laboratory is
The injection port temperature was maintained at 250~
The separations were accomplished on a 5% phenyl, 95%
methyl silicon capillary column (25 m x 0.20-ram i.d., 0.33-11m
film thickness, Hewlett-Packard) with a deactivated retention
gap (5 m • 0.25-ram i.d., Restek). High-purity (99.999%) helium was used as the carrier gas. The head pressure was maintained at 150 kPa, which gave a flow rate of 0.5 mL/min at
250~ oven temperature. Splitless 1- or 2-1~Linjections were
made.
The instrument was tuned daily using perfluorotributylamine. The electron multiplier was set at autotune value for
codeine and morphine analysis and 200 V above tune value for
the 6-AMassay. A direct capillary connection to the ion source
was used, and the interface was maintained at 310~
Ions used for quantitation are given in bold type. The maximum permissible variation of qualifier ion ratios was •
6-AM quantitation. The GC temperature program was as
follows: initial temperature, 160~ held 1.00 rain; 25~
to
280~ 4~
to 300~ which was held for 2.2 rain; run
time, 13 rain. The ions for selected ion monitoring (SIM) and
integration were rn/z 402.2, 343.2, and 290.2 for 6-AM-d3and
m/z 399.2, 340.2, and 287.2 for 6-AM.
Codeine and morphine quantitation. The GC temperature
program was as follows: initial temperature, 160~ held 1.00
rain; 20~
to 290~ 4~
to 305~
which was held for 1.25 rain; run time, 12.5
rain. The ions for SIM and integration
were m/z 374.2, 346.2, and 237.2 for
codeine-d3;m/z 371.2, 343.2, and 234.2 for
codeine; m/z 432.2, 417.2, and 327.2 for
morphine-d3 and; m/z 429.2, 414.2, and
324.2 for morphine.
Qualitative scan mode for opiates. The
.~
GC temperature program was as follows:
<
2
initial temperature 140~ 10~
to
280~ 3.5~
to 300~ which was held
for 1.79 rain; run time, 18 rain. The scan
range was m/z 45-550.
10.50
11.00
11.s0
12.00
12.50
13.00
13.50
The prepared residues of the opiate assay
were analyzed twice.The first injection used
Time (min)
8IM mode for the quantitation of codeine
Figure 2. Full spectrum total ion current chromatogram obtained from urine of one of the study
and morphine. A second injection of the
subjects. The specimen was prepared according to procedure given in the Experimental section
same sample using scan acquisition was
for opiate assay. Retention times correspond with TMS derivatives of codeine-d3 and codeine
made for qualitative identification of any
(peak 1), morphine-d3 and morphine (peak 2), and 6-acetylmorphine (peak 3). In this specimen,
drug included in Mixtures I and II. Identificodeine and morphine concentrations were below the method limit of quantitation.
cation was based on peak retention times
511
Journal of Analytical Toxicology, Vol. 21, October 1997
80,000 ng/mL. Although more specimens had detectable
6-AMconcentrations at higher morphine concentrations, there
was no observable correlation between the ratio and the MOR
concentration9
Forty-four urine specimens from the brothers were saved for
analysis during a period of five months. The seven specimens
which tested positive for opiates by enzyme immunoassay
(EIA) were tested quantitatively for total morphine, total
codeine, and 6-AM. The data in Table I show that the single
sample in which 6-AMwas not detected was the only specimen
that contained codeine. In the specimens containing 6-AM,
all 6-AM/MORratios were greater than 100%. The 37 urines
that tested negative for opiates by EIA were
399 A
analyzed for 6-AM (Table II). Both subjects
Scan 630 (13.255 min): 0801028.D (*)
produced specimens with trace concentra340
tions of 6-AM in the absence of a positive
opiate
screen. The concentration range of
73
287
6-AM
in
the specimens in which it was de204
I
tected was 1.2-10.3 ng/mL.
94
14.~ I 179
384
] IlL .I. _,.I . ._9. . ,,..,,.
. .
,LL .... ,.,,k.L, ,U,.
9
40% of the cutoff concentration9All qualifying ion ratios were
within acceptable limits down to 6.3 ng/mL, which exceeded
our normal criteria. For this study, the range was extended to
the limit of detection, 0.8 ng/mL, by omitting ion m/z 287.
Urines (n = 33) obtained from treatment programs that had
MOR concentrations greater than 3500 ng/mL were assayed for
6-AM. The percentage ratio of 6-AM to MOR is plotted versus
total morphine concentration in Figure 4. The average ratio
was 09
which was consistent with reported values9 The
highest 6-AM/MOR ratio from these typical specimens was
4.3%. Several specimens had negligible 6-AM concentrations
with corresponding morphine concentrations greater than
50
100
150
200
250
300
350
399 B
#58: 6-Acetylmorphine (TMS Derivative) (*)
340
73
287
9 4~. j :,., . ' . . - - . ' : .-'.-.'-_-:--. 2..~4 _..:_.:...~,. ,.282
/ 59 L 94 124 146162179 ~ 229 253_ ,[
50
100
150
200
250
[
.32L4 ' - ' - .'- . , ~ 356 384
300
350
Figure 3. A, mass spectrum obtained at the apex of peak 3 from Figure 2. Instrumental conditions
were as described in the Experimental section (GC-MS conditions). B, mass spectrum obtained
from TMS derivative of 6-acetylmorphine after derivatization and analysis of scan Mixture II.
Instrumental conditions were as described in the Experimental section (GC-MS conditions).
5-
o
4.
v
o
o
E
o
#__2
0
0
o
,<
,,a
0
o
i
o
o
o
---@:X]D.
0
o
. ,o...
20000
o
o
9 , ....
40000
, ....
60000
Q ....
80000
,
9
100000
.o.
9
,
120000
Total morphine (ng/mL)
Figure
4. Plot of 6-acetylmorphine/total morphine (%) versustotal morphine concentration. These
data obtained from 33 typical urine specimens which contained more than 3500 n~mL of total
morphine. No ratio of 6-acetylmorphine/total morphine observed in this set of specimens was
greater than 5%.
512
Discussion
The specimens included in the study were
received as clinical samples. As such, the
donor identities were known, and analysis
was not subject to the restraints of forensic
protocol. Hospital policy precluded direct
contact with the subjects, and specimen access was limited to the urine received for
toxicology testing.
When the pattern of elevated concentrations of 6-AMwith negligible total morphine
was observed, five possibilities were considered: artifact, a drug other than heroin was
involved, timing of the specimen donation
relative to drug administration, route of
administration, and impairment of the
metabolic pathway.
Artifact was initially considered a strong
possibility. Environmental contamination
of a specimen with heroin could account
for the observed pattern in a given specimen. Conceivably, a subject who had not
used opiates, but who had heroin-contaminated hands during sample collection, could
introduce heroin into an otherwise drugfree specimen. Subsequent hydrolysis of
heroin would produce substantial 6-AMwith
minimal morphine concentrations within
the first hours after contamination. Artifact
became progressively less probable as subsequent samples that reproduced the unusual 6-AM/MORpattern were received.
The route of administration affects the
metabolism of drugs. There are various
routes of opiate administration, including
Journal of Analytical Toxicology, Vol. 21, October 1997
Table I. Urinary Distribution of Opiates from Study Subjects after Positive
EIA* Screen
Subject
EW
EW
EW
AW
AW
EW
EW
MOR
(ng/mL)
6-AM
(ng/mL)
6-AM/MOR
(%)
309
118
313
363
183
209
175
642
379
326
n.d.
2152
1220
728
208
321
104
1176
584
416
COD
(ng/mL)
n.d.
n.d.
n.d.
151
n.d.
intravenous, intramuscular, and subcutaneous injection; smoking; insufflation
(snorting); and oral ingestion. Of these, intravenous injection and oral ingestion represent extremes of the drug administration
spectrum. Other routes combine the
metabolic consequences of intravenous or
oral administration. Although oral heroin is
more readily absorbed than morphine, there
is a 100% first-pass effect (15). No orally
n.d.
n.d.
* Abbreviations:EIA, enzyme immunoassay; MOR, total morphine; 6-AM, 6-acetylmorphine; COD,total
codeine; n.d., not detected.
Table II. Urinary 6-AM* from Study Subjects after
Negative EIA Screen
Month
Subject
6-AM
(ng/mL)
6
6
6
6
6
6
7
7
7
7
7
7
7
7
7
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
9
9
9
9
10
AW
AW
AW
EW
EW
EW
AW
AW
AW
AW
EW
EW
EW
EW
EW
EW
AW
AW
AW
AW
AW
AW
AW
AW
AW
EW
EW
EW
EW
EW
EW
EW
AW
AW
EW
EW
AW
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
3.6
1.6
1.9
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
1.2
n.d.
3.8
n.d.
n.d.
n.d.
10.3
4.6
n.d.
n.d.
3.9
2.5
n.d.
* Abbreviations:EIA, enzyme immunoassay;6-AM, 6-acetylmorphine;n.d., not
detected.
ingested heroin or 6-AMreaches the systemic
circulation. Intravenous administration provides 100% bioavailability, but carefully
controlled studies have not demonstrated predominant 6-AM excretion in typical subjects
(14).
The timing of specimen collection relative to drug administration can have a dramatic effect on the relative concentrations of all urinary opiate metabolites. Studies with periodic
timed urine collection after heroin administration gave a maximal 6-AM/MORratio of 8% (14).
The appearance of a new "designer drug" yielding 6-AMas a
primary metabolite would have produced many similar
6-AM/MOR patterns in our geographical area. However, this
was not observed. Heroin can degrade to 6-AM before administration. 6-AMas a parent drug has not been studied, but the
rapid metabolism of heroin to 6-AM metabolically would be
similar to direct administration of 6-AM.The parent drug was
probably heroin.
The excretion pattern observed on multiple occasions in
these closely related subjects suggests a defect in the heroin
metabolic pathway. The observed concentrations of 6-AM in
urine well above the proposed 10-ng/mL cutoffwithout greater
than cutoff concentrations of MOR presents a general possibility of false-negative opiate use reports. The data presented in
this paper suggest that if 6-AM is assayed only when total morphine is elevated, then some members of the heroin-using
population may evade detection. There has been ongoing discussion in the forensic community concerning the guidelines
for opiate testing. Testing for 6-AM without preliminary
codeine and morphine determinations has been discussed as a
possible approach. This design could distinguish heroin use
from the prescription use of opiate narcotics and poppy seed
consumption in the general population.
References
I.
2.
3.
4.
M.A. ElSohlyand A.B. Jones. Morphine and codeine in biological
fluids: approaches to source differentiation. Forensic Sci. Rev. 1:
14-21 (1989).
E.J. Cone and W.D. Darwin. Rapid assayof cocaine, opiates and
metabolites by gas chromatography-mass spectrometry. J. Chromatogr. 580:43-61 (1992).
P.T.Smith, M. Hurst, and C.W. Gowdey. Spontaneous hydrolysis
of heroin in buffered solution. Can. J. Physiol. Pharmacol. 56:
665-67 (1978).
O. Lockridge, N. Mottershaw-Jackson, H.W. Eckerson, and B.N.
La Du. Hydrolysis of diacetylmorphine (heroin) by human serum
cholinesterase. J. Pharmacol. Exp. Then 215:1-8 (1980).
513
Journal of Analytical Toxicology,Vol. 2I, October 1997
5.
6.
7.
8.
9.
10.
514
B.A. Goldberger, W.D. Darwin, T.M. Grant, A.C. Allen, Y.H.
Caplan, and E.J.Cone. Measurement of heroin and its metabolites
by isotope-dilution electron-impact mass spectrometry. Clin.
Chem. 39:670-75 (1993).
E.J. Cone, P. Welch, B.D. Paul, and J.M. Mitchell. Forensic drug
testing for opiates, I11. Urinary excretion rates of morphine and
codeine following codeine administration. J. Anal. Toxicol. 15"
161-66 (1991 ).
R. Dybowski and T.A. Gough. A study of transacetylation between
3,6-diacetylmorphine and morphine. J. Chromatogr. Sci. 22:
465-69 (1984).
U. Boerner, R.L. Roe, and C.E. Becker. Detection, isolation and
characterization of normorphine and norcodeine as morphine
metabolites in man. J. Pharm. Pharmacol. 26" 393-98 (1974).
G. Fritschi and W.R. Prescott, Jr. Morphine levels in urine subsequent to poppy seed consumption. Forensic Sci. Int. 27:111-17.
(1985).
B.D. Paul, J.M. Mitchell, and L.D. Mell, Jr. Gas chromatography/electron impact mass fragmentometric determination of
urinary 6-acetylmorphine, a metabolite of heroin. J. AnaL ToxicoL
13' 2-7 (1989).
11. P. Kintz, A. Tracqui, B. Ludes, P. Mangin, A.A. Lugnier, and A.J.
Chaumont. Identification of 6-monoacetylmorphine, as an indicator of heroin abuse. Acta Med. Leg. Soc. 39" 464-69 (1989).
12. E.J. Cone and P. Welch. Time course of detection of 6-acetylmorphine in urine after heroin administration. NIDA Research
Monographs 95:449 (1989).
13. S.Y.Yeh, C.W. Gorodetzky, and R.L. McQuinn. Urinary excretion
of heroin and its metabolites in man. ]. Pharmacol. Exp. Ther. 196"
249-56 (1975).
14. E.J.Cone, P. Welch, J.M. Mitchell, and B.D. Paul. Forensic drug
testing for opiates: I. Detection of 6-acetylmorphine in urine as an
indicator of recent heroin exposure; drug and assayconsiderations
and detection times. J. Anal. Toxicol. 15:1-7 (1991 ).
15. C.E. Inturrisi, M.B. Max, K.M. Foley, M. Schultz, S.U. Shin, and
R.W. Houde. The pharmacokinetics of heroin in patients with
chronic pain. N. Eng. J. Mecl. 310:1213-17 (1984).
Manuscript received March 26, 1997;
revision accepted May 28, 1997.