Urinary Excretion Rates of Ketamine and Norketamine Following ...

[ TechnicalNote
Journal of Analytical Toxicology, Vol. 28, July/August 2005
Urinary Excretion Rates of Ketamine and Norketamine
Following Therapeutic Ketamine Administration:
Method and Detection Window Considerations
Piotr Adamowicz* and Maria Kala
Institute of Forensic Research, ul. Westerplatte 9, 31-033 Krakow, Poland
Abstract I
Ketamine is widely used in veterinary medicine. Its medical
application in humans is limited to children because in adults it
induces severe psychedelic episodes9 In recent years, teenagers
have abused ketamine as a recreational and "club drug"
because of its hallucinogenic and stimulant effects. Ketamine
is also misused as a "date-rape" drug (to induce amnesia in
unsuspecting victims). Sensitive gas chromatography-mass
spectrometry-negative chemical ionization (GC-MS-NCI) and
liquid chromatography-mass spectrometry-atmospheric pressure
chemical ionization (LC-MS-APCI) methods were applied for the
simultaneous quantification of ketamine and its major metabolite,
norketamine, in urine. Urine samples were collected from
hospitalized children who had received ketamine as an anesthetic.
Individual urine samples were collected up to 16 days after drug
administration. Using the GC-MS-NCI method, ketamine was
detected in the urine of the children from only the day of drug
administration up to 2 days after drug administration, its
concentrations ranged from 29 to 1410 ng/mL. Norketamine
(measured in concentrations of 0.1-1442 ng/mL) was detected up
to 14 days. Using the LC-MS-APCI method, norketamine was
detected up to 6 days after drug administration, ranging in
concentrations of 2-1559 ng/mL, while ketamine was detected up
to 11 days (2-1204 ng/mL). In the urine taken from one child,
ketamine was not detected through the entire 16-day period using
both methods. The detection window for the analytes is highly
dependent on the method used for determination and varies
between individuals.
Introduction
Ketamine (Figure 1) was first synthesized in 196]-1963 at
Parke Davis Labs in Michigan by Calvin Stevens while he was
searching for a phencyclidine (PCP) substitute (1). Ketamine
was patented by Parke Davis for use as an anesthetic in humans
9 Author to whom correspondence should be addressed: Piotr Adamowicz, ul. Westerplatte 9,
31-033 Krakow, Poland. E-mail: padamowi@ies.krakow.pl
and animals in 1966. In the late 1960s, ketamine was used as a
field anesthetic during the Vietnam War.
At one time, ketamine was perceived as one of the safest
drugs used in surgery as a general anesthetic because it de-
presses breathing less than other available anesthetics (2). Later
it was noticed that ketamine often induces very unusual and
substantial changes in perception and emotions (psychedelic
episodes) (3,4).
Ketamine was also used in the treatment of alcoholism and
heroin addiction. It was also administered to incurable patients
with the aim of alleviating fear of death (5). A study on the ap-
plication of ketamine for the treatment of anorexia was carried
out at the University of Cambridge in recent years (6).
Currently, ketamine is not frequently used for treatment of
humans because it induces psychedelic episodes in patients, es-
pecially adults. There are an increasing number of reports about
patients that have become addicted to ketamine. It is used more
frequently in children (e.g., during dental surgery). Surgeons in
small private clinics may prefer it. Ketamine is also broadly
used in veterinary surgery as a general anesthetic during minor
operations (7-9).
The narcotic effects of ketamine can be compared to those of
PCP, and the hallucinogen action is similar to that of LSD (10).
The psychological effects include nice dreams, vivid imaginings,
hallucinations, and unexpected delirium (11). Ketamine's effects
depend on the dose. At lower doses it causes mild intoxication,
CI
Figure 1. Chemical structure of ketamine.
376 Reproduction (photocopying) of editorial content of this journal is prohibited without publisher's permission.
ClH3

Journal of Analytical Toxicology, Vol. 28, July/August 2005
dreamy thinking, disturbances of speech, hearing and seeing,
lack of muscle coordination, disorientation, anxiety, disinhibi-
tions, euphoria, seeing the world differently, and irrational be-
havior. Higher doses cause great difficulty in moving, respiratory
disturbances, seizures, and nausea. Extreme doses produce com-
plete disassociation from reality and loss of consciousness, hal-
lucinations, out-of-body experiences, and so-called "near-death
experiences". Frequent intake of ketamine can lead to psycho-
logical and physical dependency and tolerance (12-14).
Deaths by overdose in the absence of other drugs are excep-
tionally rare (5,15). Overdose in the case of ketamine is a very
relative term, because doses used by drug-addicts are typically
lower than necessary for anesthesia. The highest therapeutic
dose is 13 mg/kg, while doses taken to induce psychedelic effects
rarely exceed 2 mg/kg. Accidental deaths such as falling from a
great height, death by hypothermia, car accident, or drowning
in a bathtub are the most common ketamine-related deaths
(7).
Ketamine is rapidly metabolized to an active metabolite, nor-
ketamine, and an inactive metabolite, 6-hydroxynorketamine.
The major pathway is N-demethylation to norketamine by the
microsomal cytochrome P450 system (8). Norketamine is also
hydroxylated to 6-hydroxynorketamine, conjugated, and ex-
creted in the urine. Hydroxylation and conjugation of glu-
curonic acid with norketamine and its hydroxylated metabolites
generate water-soluble compounds to facilitate urinary excretion
(9). Norketamine also undergoes dehydrogenation to dehy-
dronorketamine. It had been suggested that dehydronorke-
Table I Urinary Excretion of Ketamine and Norketamine Following Ketamine Administration to Children*
Concentrations (ng/mL) Measured by Concentrations (ng/mL) Measured by
LC-MS-APCI GC-MS-NCI LC-MS-APCI GC-MS-NCI
Day Ketamine Norketamine Ketamine Norketamine Day Ketamine Norketamine Ketamine Norketamine
Case 1
0-1 urine samples not collected
2 - 50 - 57
3 - 7 - 3
4 - 5 - 2
5 - 5 - 0.4
6 - 4 - 0.4
7 - - 0.2
8 - - 0.06
9 - - 0.1
10 - - 0.2
11 - - 0.2
12 - - - 0.1
13 - - 0.08
14 - - - 0.05
15-16 urine samples tested negative
Case 2A
0 urine sample not collected
1 41 264 41 227
2 4 18 - 11
3 - 3 - 2
4 - - - 0.4
5 - - - 0.6
Case 2B
0 799 409 695 534
1 52 387 58 325
3 3 2 - 2
5 - - - 0.1
7 2 - - -
9 6 - - -
11 4 - - -
Case 2C
0 urine sample not collected
1 813 548 1181 743
2 195 417 296
3 17 85 -
4 7 17 -
5 3 6 -
Case 3
0 urine sample not collected
1 161 527
2 110 34
3 - 5
4 - 3
5 - 2
6
7
Case 4
0 502 1276
1 12 206
2 - 5
3 - 2
5 - 3
6
7-15 urine samples tested negative
Case 5
179
156
586
496
0 urine sample not collected
1 30 166 29 147
Case 6
82
13
3
430
52
2
2
1182
0 1204 1559 1410 1442
0.7
0.1
184
1
1 467 535 642 553
2 55 52 71 72
3 - 6 - 3
4 - 4 - 1
5 - 3 - 0.6
6 - - 0.1
* Day 0: the day of ketamine administration; Day 1 : the first day after ketamine administration; Cases 2A, 2B, and 2C represent urine samples collected from one patient to
whom ketamine was administered three times during two-year period.
0.06
0.6
0.1
0.07
377

tamine was an artifact of the analytical procedure [using a gas
chromatography (GC) technique[ rather than a metabolite (16).
Other authors (17) have detected ketamine, norketamine, and
dehydronorketamine in urine by liquid chromatography-mass
spectrometry (LC-MS). Norketamine has one-third the activity
of ketamine (18).
Since the early 1990s, interest in this substance has grown
among young people and an increasing number of reports have
appeared about recreational use of this drug (19-22). Ketamine
is a "club drug" and its illicit use by teenagers at rave parties has
also been reported. The major source of ketamine is diversion
from veterinary clinics. It is also smuggled from countries
where it is not legally controlled. Due to complex synthesis
and difficulties with buying precursors, solvents, and reagents,
ketamine is not manufactured in clandestine laboratories. In
pharmaceutical preparations, ketamine is sold in liquid form
and the powder form is prepared by boiling off the solution
(18). It can be taken via intramuscular, intravenous, intranasal,
oral, and rectal routes. Ketamine can also be smoked, some-
times in combination with marijuana or tobacco (5,23). Oral
doses are prepared from the powder by dissolving it in water,
juice, or alcoholic beverages.
Recently it has also been identified as a "date-rape" drug used
for drugging unsuspecting victims and then raping them while
the victim is still under its influence. In a typical scenario, the
perpetrator surreptitiously adds ketamine to the alcoholic bev-
erage of an unsuspecting person, who is subsequently sexually
assaulted while under the influence of this substance. Many
victims do not report the incident until several days after the
event (24-26).
These situations create a demand for sensitive analytical
methods to reveal the presence of the drug and/or metabolites
in biological specimens collected from the subject. An impor-
tant parameter in drug testing for forensic purposes is the de-
tection window (i.e., how long after drug administration a
person tests positive for the drug or metabolite).
Obviously, detection times are highly dependent upon a
number of factors including dosage, individual rates of
metabolism and excretion, method specificity, and detection
limits. Consequently, detection times may vary between
methods, and it is important to characterize the performance of
new methods with clinical drug specimens obtained under con-
trolled conditions.
Many analytical methods for the determination of ketamine
and norketamine in biological materials are described in the lit-
erature. Initially, conventional (27) and two-dimensional (28)
thin-layer chromatography methods were applied, but these
methods require high specimen volume and often lack the re-
quired sensitivity. GC with nitrogen-phosphorus detection or
electron capture detection methods, have been used for bio-
transformation and disposition studies. However, validation pa-
rameters were not defined or limits of detection (LOD) ranged
from 10 to 100 ng/mL, which is insufficient. Many authors de-
veloped HPLC with UV detection methods for separation, de-
tection, and quantification of ketamine and norketamine, which
can attain LODs of 5 ng/mL (29-32). Only GC-MS or LC-MS
methods provide the sensitivity, selectivity, and specificity nec-
378
Journal of Analytical Toxicology, Vol. 28, July/August 2005
essary for qualitative and quantitative data needed in forensic
studies on a single ketamine exposure used as the date rape
drug. These methods have been developed and described re-
cently (17,33).
This paper describes two analytical methods, GC-MS-negative
chemical ionization (NCI) and LC-MS-atmospheric pressure
chemical ionization (APCI), and their application to the analysis
of urine samples collected from hospitalized children who re-
ceived ketamine as an anesthetic. The GC-MS-NCI method was
published previously by Negrusz et al. (34) and the authors of
this article developed the LC-MS-APCI method.
Materials and Methods
Chemicals
Ketamine, norketamine, ketamine-d4, and norketamine-d4
were purchased from Cerilliant Corporation (LGC Promochem,
Warszawa, Poland). The enzyme [3-glucuronidase (Type H-2
crude solution, 110,350 units/mL from Helix pomatia) and
heptafluorobutyric anhydride (HFBA) were acquired from
Sigma-Aldrich (Poznan, Poland). The HCX Isolute | (10-mL,
200-rag) extraction columns (product of International Sorbent
Technology, Hengoed, U.K.) were supplied by Able & Jasco
(Krakow, Poland). All solvents and reagents were of analytical
grade.
Biological material
Urine samples were collected from six hospitalized children
(age 4-13 years, weight 17-68 kg) who had received a single in-
travenous dose of ketamine as an anesthetic for short surgical
procedures. One child received ketamine three times during a
two-year period (case 2A, 2B, and 2C, Table I). The doses ranged
from 0.75 to 1.59 mg/kg. Individual urine samples were col-
lected every day or once every two days for 4-16 days. If the
urine samples were not analyzed immediately, they were stored
up to one month at-18~ prior to analysis.
For validation of the LC-MS-APCI method, control urine
samples were taken from healthy persons with no history of ke-
tamine use.
Solid-phase extraction (SPE)
To the urine samples (2 mL for GC-MS-NCI procedure or
1 mL for LC-MS-APCI procedure), an appropriate internal
standard (IS, 1 ng of norketamine-d4 in 10 tJL of methanol for
the GC-MS-NCI method and 100 ng each of norketamine-d4
and ketamine-d4 in 10 IlL of methanol, for the LC-MS-APCI
method) was added. This was followed by the addition of 1 mL
of 0.1M acetate buffer (pH 5.5) and 50 IJL of ~-glucuronidase
before the specimens were incubated for 90 min at 37~ After
this, 1 mL of 1.93M acetic acid and deionized water (10 mL for
GC-MS-NCI or 5 mL for LC-MS) were added to the samples
and applied on the mixed-mode Isolute HCX SPE columns.
Columns were preconditioned with methanol (3 mL), deion-
ized water (3 mL), and 1.93M acetic acid (1 mL).
The pretreated sample was slowly passed through the column

Journal of Analytical Toxicology, VoL 28, July/August 2005
(approximately 5 rain) followed by rinsing with 3 mL of deion-
ized water, 1 mL of 0.1M HC1, and 3 mL of methanol. The
column was dried under vacuum for 5 rain. The retained ana-
lytes were eluted with a mixture of methylene chloride/iso-
propanol/ammonium hydroxide (78:20:2, v/v) under gravity.
The eluates were evaporated to dryness under a stream of air. In
cases of analyte concentrations exceeding the upper level of
the respective calibration curve, the sample was diluted and the
analysis was repeated.
GC-MS-NCI analysis
The dry residues were derivatized with 50 1JL of HFBA at
60~ for 30 rain. After incubating, the excess derivatizing
reagent was evaporated under air and the dry residue reconsti-
tuted in 50 I~L of ethyl acetate before I IJL was injected into the
GC-MS system.
Quantitation of ketamine and norketamine was carried out
using the Agilent Technologies 6890 series GC equipped with a
5973 series mass selective detector (MSD) and a 6890 series au-
tosampler (Agilent Technologies, Wilmington). The NCI mode
was applied using methane as the reagent gas. The separation
of analytes was performed with the use of a HP-5MS fused silica
capillary column (30-m 0.25-mm i.d., 0.25-1Jm film thick-
ness). The capillary inlet system was operated in the splitless
mode. Instrumental conditions were as follows: injection port,
280~ GC temperature program, 60~ for 1 min, ramp to
310~ at 30~ and hold 3 min; transfer line, 280~ source,
200~ quadrupole, 230~ The flow rate of carrier gas (helium)
was I mL/min. The quantitative (underlined) and qualifier ions
monitored for each derivatized compound were ketamine, m/z
226, 357; norketamine, m/z 383 and 399; and norketamine-d4,
m/z 387 and 403.
LC-MS-APCI analysis
The dry residue (after SPE and without derivatization) was re-
constituted in 100 lJL of an acetonitrile (ACN)/water mix (1:4
v/v). A 20-1~L sample was injected by autosampler into the
LC-MS system.
Analysis was performed with the HP-1100 series LC coupled
to a MS equipped with an APCI interface (Hewlett Packard,
Wilmington).
The separation of analytes was performed with the use of a
LiChroCART Purospher STAR RP-18e column (55- 4-mm
i.d.) (Merck, Darmstadt, Germany) thermostated at 25~ The
mobile phase consisted of 0.1% (v/v) formic acid in water and
ACN. The flow rate was 0.8 mL/min. All analyses were carried
out in gradient mode: 0 min-10% ACN, 5 min-40% ACN, 6
min-10% ACN, and 8 min-10% ACN.
Nitrogen generated by a Whatman apparatus was used as a
nebulizing gas. First, an autotuning procedure was carried out.
Then optimization of MS parameters was accomplished by flow
injection analysis to obtain the most intense ions for selected
ion monitoring mode. Ketamine and norketamine at concen-
trations of 100 ng/mL in mobile phase were individually injected
directly into the MSD without chromatographic separation and
analyzed in full-scan mode (m/z range 50-500 ainu). For both
analytes, the pseudomolecular ions of ketamine (m/z 238) and
of norketamine (m/z 224) were selected as the most repro-
ducible and intense. Other parameters were as follows: frag-
mentor voltage, 60 V; vaporizer temperature, 330~ capillary
voltage, 4200 V; drying gas flow, 7 L/rain; temperature, 300~
nebulizer pressure, 35 psi; corona current, 4.5 IIA. All data were
acquired and analyzed by HP software, ChemStation version
A.06.03 for Windows NT.
The calibration curves for ketamine and norketamine in urine
consisted of 11 points for each compound, which covered the
range of 0.5-2000 ng/mL. The calibrator solutions were pre-
pared by adding known amounts each of the IS (ketamine-d4
and norketamine-d4, 100 ng/mL each), ketamine, and norke-
tamine to control urine (0, 0.5, 1, 2, 5, 10, 20, 100, 500, 1000,
and 2000 ng/mL). The samples were hydrolyzed, extracted, and
analyzed by LC-MS-APCI in the same manner as described for
the patients' urine samples. Peak-area ratios (ketamine/ke-
tamine-d4; m/z 238/242 and norketamine/norketamine-d4; m/z
224/228) were calculated for each standard and plotted against
the known concentration of the standard.
The method was validated by repetitive (at least three times)
analysis of two different concentrations of spiked control urine
samples containing 40 and 750 ng/mL of both target analytes
(on the same day and over a period of three weeks).
LOD, lower limit of quantification (LLOQ), and limit of lin-
earity (LOL), as well as extraction recovery for ketamine and
norketamine (at concentrations of 40 and 750 ng/mL from
spiked urine in comparison with unextracted drug solutions)
were determined. Calculations were performed using Merck's
Validation Manager Program.
Results
The GC-MS-NCI method (34) had an LOQ of 20 ng/mL for ke-
tamine and 0.05 ng/mL for norketamine, and displayed a LOL
across a concentration range of 20-1000 ng/mL and 0.050-1500
ng/mL, respectively.
The LC-MS-APCI method was characterized by the same val-
idation parameters for both compounds: LOD of 0.5 ng/mL,
LLOQ of 2 ng/mL, and LOL of 2-2000 ng/mL. Linear regression
correlation coefficients of the calibration curves were 0.9997 for
ketamine and 0.9999 for norketamine. Recovery of ketamine
from urine was 107.86 3.66% at 40 ng/mL and 100.33
1.87% at 750 ng/mL. Recovery for norketamine at the same low
and high concentrations was 101.18 3.69% and 100.59
1.75%, respectively. All values were high, but comparable and
reproducible. Coefficient of variations of the intra- and in-
terassay precision did not exceed 4% for ketamine and norke-
tamine at low concentration (40 ng/mL). These data for both an-
alytes at the 750-ng/mL concentration were slightly lower. For
ketamine the coefficient of variation was less than 2%.
On the basis of the successful validation, both methods were
applied to the determination of ketamine and norketamine in 62
urine samples collected from six hospitalized children. Urinary
excretion profiles of ketamine and norketamine were presented
in Figures 2-5 and Table I.
After a single intramuscular ketamine dose, the drug was de-
tected in the urine samples of five children. By the GC-MS-NCI
379

method, ketamine was determined in the urine of two chil-
dren up to i day after exposure in concentrations ranging from
41 to 695 ng/mL; in the next two children up to 2 days after
drug administration in concentrations ranging from 71 to 1410
ng/mL, and in one child only on the day of drug administration,
when its concentration was 586 ng/mL. Norketamine was de-
tected in the urine of two children up to 6 days after dosing (in
concentrations ranging from 0.07 ng/mL to 1442 ng/mL), in
one child up to 5 days (in concentrations of 0.6-227 ng/mL), in
another child up to 7 days (0.06-430 ng/mL), and in the last
child up to 14 days (0.05-57 ng/mL).
Using the LC-MS-APCI method, ketamine was detected (at
concentrations of 4-1204 ng/mL) in three children up to two
days after exposure and in two children up to one day (at con-
centrations of 12-502 ng/mL) after exposure. Norketamine was
detected up to three (at concentrations of 2-409 ng/mL), five
(2-1559 ng/mL), and six days (4-50 ng/mL) after drug admin-
istration.
Using either method, neither ketamine nor norketamine were
detected in the urine taken from one child through the entire
16-day period.
Data from Case 2 (Table I) demonstrated that repeated doses
of ketamine (three times during a two-year period) resulted in
its slower elimination. After the second dose (case 2B), the
elimination of parent ketamine was extended to 11 days, and
after the third dose it was extended to 5 days after drug admin-
2
mc~e !
iC~se 2A
DC~se 2B
, ~ Case 2C
i Case 3
! Case 4
i
I 9 Case 5
[ [] Case 6
Figure 2. The urinary excretion profiles of ketamine for six hospitalized
children determined by GC-MS-NCI.
2 i RCase 1
: 9 Case 2A
DCase 2B
D Ca-se 2C
it Case 3
m Case 4
[lCase 5 1
[oca.se 6 [
Figure 3. The urinary excretion profiles of norketamine for six hospital-
ized children determined by GC-MS-NCI.
380
Journal of Analytical Toxicology, Vol. 28, July/August 2005
istration. After each dose norketamine was excreted in the same
5-day period.
Overall elimination times of ketamine varied between the
different children and the different methods.
Discussion
Because ketamine has become a popular club drug and date-
rape drug, it is a subject of interest to forensic toxicologists, es-
pecially regarding its detection times. Detection times indicate
how long after drug administration a person excretes a drug or
metabolite at a concentration above a specific method LOD.
This makes sensitive methods with low LODs essential. The
methods used in this study allowed for quantification of ke-
tamine and norketamine at very low concentrations. The
GC-MS-NCI method had an LOQ of 20 ng/mL for ketamine and
0.05 ng/mL for norketamine, and the LC-MS-APCI method
provided an LOQ of 2 ng/mL for both compounds. The applied
LC-MS-APCI method is more sensitive than elaborated by
Moore et al. (17) who measured ketamine and norketamine
with a LOD of 4 ng/mL for both analytes. A previously reported
GC-MS method achieved an LOQ for ketamine of 13 ng/mL and
an LOQ for norketamine of 9 ng/mL (35).
Both applied methods have advantages and disadvantages.
~2
=
9 Case I
iCase 2A
[]Case 2B
[Case 2C
i 9 Case 3
D Case 4
9 Case 5
[] Case 6
Figure 4. The urinary excretion profiles of ketamine for six hospitalized
children determined by LC-MS-APCI.
BCase 1
9 C~tse 2A
DC~se 213
DC~se 2C
9 Case 3
9 Case 4
9 Case 5
DC~se 6
Figure 5. The urinary excretion profiles of norketamine for six hospital-
ized children determined by LC-MS-APCl.

Journal of Analytical Toxicology, Vol. 28, July/August 2005
The LC-MS-APCI procedure is easier and faster (the derivati-
zation step is omitted). The GC-MS-NCI method is character-
ized by a very low LOD for norketamine. In cases where urine
samples were collected a long time after ketamine administra-
tion, the GC-MS-NCI method seems to be most suitable. Using
both methods provides the toxicologist with a high level of
confidence in their results.
Both methods are very expensive and the procedures are time
consuming. Therefore, they are not complementary, but can be
regarded as alternative. Both can be used as independent
screening methods for ketamine and norketamine, and can
also be used for confirmation and quantitation of these analytes.
Using the GC-MS-NCI method, norketamine can be detected
for an extended period of time. Finding norketamine in a urine
sample is forensically important because its status as a bio-
transformation product reduces the likelihood of it as a con-
taminant.
Most authors have detected ketamine in urine up to 48-72 h
after administration of a single dose (36). Our study confirmed
these findings because ketamine was detected up to 48 h after
a single therapeutic dose to children. Multiple-doses of ke-
tamine (Case 2, Table I) extended its elimination time to 11
days. This is consistent with the report by Jansen et al. (37) who
described that frequently repeated dose of ketamine prolonged
its elimination. In our study norketamine was detected in urine
samples up to 14 days after administration of a single intra-
venous dose of ketamine to children. Negrusz et al. (34) re-
ported that after a single intramuscular dose of ketamine, nor-
ketamine remained in urine of nonhuman primates throughout
the entire 35-day study period in four out of five animals. The
detection times of ketamine and/or its metabolite vary a lot in
both studies, but the subjects and the routes of ketamine ad-
ministration are different. Both routes are different than in
recreational ketamine use or in a ketamine-facilitated sexual as-
sault scenario when the drug is taken orally. Variability be-
tween individuals and species, as well as various routes of ke-
tamine administration, highly influence its metabolism and
elimination. Ketamine elimination in Rhesus monkey is similar
to human elimination (38,39). The pharmacokinetics in chil-
dren is not very different than in adults, although in children
more norketamine is formed after intravenous and intramus-
cular administrations (40,41). Ketamine is eliminated two times
faster in children (42). Oral administration of ketamine pro-
duces higher plasma levels of norketamine due to first pass
metabolism (43).
This study suggests that in cases of oral ingestion of ke-
tamine, the parent compound and its major metabolite can be
detected in urine for the same or longer time with the use of the
described chromatographic methods.
To detect a non-medical use of ketamine, urine samples
should be collected up to several days after the suspected ad-
ministration. Ketamine and its metabolite remain in human
urine for an extended period of time.
Conclusions
Recently, an increased number of reports of illicit use of
ketamine have been observed. Ketamine is abused by teenagers
as a club drug and also used as a date-rape drug. This paper pre-
sents the elimination of ketamine and its major metabolite,
norketamine, in urine after single (and in one case multiple) in-
travenous dose of ketamine in six children. Sensitive, accurate,
and precise GC-MS-NCI and LC-MS-APCI methods for detec-
tion of ketamine in urine were applied to urine samples.
As shown, the detection window of the analytes is highly de-
pendent on the method used for the analysis, and is also affected
by the interindividual variability. Ketamine was detected up to
two days with the use of the GC-MS-NCI method or up to 11
days with the use of the LC-MS-APCI method. Norketamine was
detected in urine up to 14 days with the GC-MS-NCI method
and up to 6 days with the LC-MS-APCI method.
These results are important for the forensic toxicology com-
munity because they demonstrate the length of time after ke-
tamine administration that a person may continue to test pos-
itive for the drug or metabolite. The authors suggest that urine
samples should be collected up to several days after suspected
consumption of ketamine for non-medical purposes.
References
1. T. Bowdle, A. Horita, E.D. Kharash. The Pharmacologic Basis of
Anesthesiology. Churchill Livingstone, New York, NY 1994.
2. M. Fisher. Ketamine hydrochloride in severe bronchospasm.
Anaesthesia 32:771-772 (1977).
3. J.W. Dundee, R.SJ. Clarke, and W. McCaughey. Clinical Anaes-
thetic Pharmocology. Churchill Livingstone, 1991, pp. 165-171.
4. B.K. Basak. Pharmacology for Anesthesiologist. Technomic Pub-
lishing Company, Westport, CT, 1981, pp. 29-32.
5. K. Kelly. The Little Book ofKetamine. Ronin Publishing, Berkeley,
CA, 1999.
6. I.H. Mills, G.R. Park, A.R. Manara, and R.J. Merriman. lreatment
of compulsive behavior in eating disorders with intermittent ke-
tamine infusions. Q. J. Med. 91" 493-503 (1998).
7. K.L.R. Jansen and R. Darracot-Cankovic. The non-medical use of
ketamine, part two: A review of problem use and dependence.
J. Psychoactive Drugs 33:151-158 (2001).
8. P.F. White, W.L. Way, and A.J. Trevor. Ketamine--its pharma-
cology and therapeutic uses. Anesthesiology 56:119-136 (1982).
9. D.L. Reich and G. Siivay. Ketamine: an update on the first twenty-
five years of clinical experience. Can. J. Anaesth. 36:186-197
(1989).
10. K.A. Moore, E.M. Kilbane, R. Jones, G.W. Kunsman, B. Levine, and
M. Smith. Tissue distribution of ketamine in a mixed drug fatality.
J. Forensic Sci. 42(6): 1183-1185 (1997).
11. M.M. Kochhar. The identification of ketamine and its metabolites
in biologic fluids by gas-chromatography-mass spectrometry. Clin.
ToxicoL 11 (2): 265-275 (1977).
12. S.N. Ahmed and L. Petchkovsky. Abuse of ketamine. Br. J. Psychi-
atry 137:303 (1980).
13. R.S. Blacher. The near death experience. J. Am. Mecl. Assoc. 244:
30 (1980).
14. P.F. White, J. Ham, and W.L. Way. Pharmacology of ketamine iso-
mers in surgical patients. Anesthesiology52:231-239 (1980).
15. J.R. Gill and M. Stajic. Ketamine in non-hospital and hospital
deaths in New York City. ]. Forensic Sci. 45:655-658 (2000).
16. T. Chang and A.J. Glazko. A gas chromatographic assay for ke-
tamine in human plasma. Anesthesiology36:401404 (1972).
17. K.A. Moore, J. Sklerov, B. Levine, and A.J. Jacobs. Urine conce-
trations of ketamine and norketamine following illegal comsump-
tion. J. Anal ToxicoL 25(7): 583-588 (2001).
381

18. S.B. Karch. Karch's Pathology of Drug Abuse. 3rd ed. CRC Press,
London, U.K. 2002, pp 467-471.
19. P.J. Delgarno and D. Shewan. Illicit use of ketamine in Scotland. J.
Psychoactive Drugs. 28:191-199 (1996).
20. P.A. Gill. Non-medical use of ketamine. Br. Med. J. 306:1340
(1993).
21. K. Skovmand. Swedes alarmed at ketamine misuse. The Lancet.
348:122 (1996).
22. A.L. Weiner, L. Vieira, C.A. McKay, and J.M. Bayer. Ketamine
abusers presenting to the emergency department: a case series. J.
Emerg. Med. 18:447-451 (2000).
23. D.T.W. Chan and M.F. Chan. Simultaneous determination of am-
phetamine-type stimulants, benzodiazepines and eetamine in ec-
stasy tablets. Forensic Sci. Int. 136(1): 98 (2003).
24. M.A. EISohly and S.J. Salamone. Prevalance of drugs used in cases
of alleged sexual assault. J. Anal. Toxicol. 23:141-146 (1999).
25. L.E. Ledray. The clinical care and documentation for victims of
drug-facilitated sexual assault. J. Emerg. Nuts. 27:301-305 (2001).
26. R.H. Schwartz, R. Milteer, and M.A. LeBeau. Drug-facilitated
sexual assault ('date rape'). South. Med. J. 93:558-561 (2000).
27. R. Sams and P. Pizzo. Detection and identyfication of ketamine and
its metabolites in horse urine. J. AnaL Toxicol. 11(2): 58-62 (1987).
28. J.D. Adams, T.A. Baillie, A.J. Trevor, and N. Castagnoli. Studies on
the bioformation of ketamine. 1. Identification of metabolites pro-
duced in vitro from rat liver microsomal preparations. Biomed.
Mass Spectrom. 8(11): 527-538 (1981 ).
29. H.A. Adams, B. Weber, M.B. Bachmann, M. Guerin, and
G. Hempelmann. The simultaneous determination of ketamine
and midazolam using high presure liquid chromatography and UV
detection (HPLC/UV). Anaesthesist. 41 (10): 619-624 (1992).
30. S.S. Seay, D.P. Aucoin, and K.L. Tyczkowska. Rapid high-perfor-
mance liquid chromatographic method for the determination of ke-
tamine and its metabolite dehydronorketamine in equine serum.
J. Chromatogr. 620(2): 281-287 (1993).
31. S. Bolze and R. Boulieu. HPLC determination of ketamine, norke-
tamine, and dehydronorketamine in plasma with high-purity re-
versed-phase sorbent. Clin. Chem. 44(3): 560-564 (1998).
382
Journal of Analytical Toxicology, Vol. 28, July/August 2005
32. Y. Hijazi, M. Bolon, and R. Boulieu. Stability of ketamine and its
metabolites norketamine and dehydronorketamine in human bio-
logical samples. Clin. Chem. 47(9): 1713-1715 (2001).
33. J.Y. Cheng and V.K. Mok. Rapid determination of ketamine in
urine by liquid chromatography-tandem mass spectrometry for a
high throughput laboratory. Forensic Sci. Int. 142(1): 9-15 (2004).
34. A. Negrusz, P. Adamowicz, B.K. Saini, D.E. Webster, M.P. Juhascik,
Ch.M. Moore, and R.F. Schlemmer. Detection of ketamine and nor-
ketamine in urine of nonhuman primates after a single dose of ke-
tamine using microplate enzyme-linked immunosrobent assay
(ELISA) and NCI-GC-MS. J. Anal. Toxicol. in press.
35. S.L. Chou, M.H. Yang, Y.C. Ling, and Y.S. Giang. Gas chromatog-
raphy-isotope dilution mass spectrometry proceeded by liquid-
liquid extraction and chemical derivatization for the determination
of ketamine and norketamine in urine. J. Chromatogr. B 799:
37-50 (2004).
36. C. Dollery. Therapeutic Drugs. Volume 2. Churchil Livingstone,
London, U.K., 1999, pp K3-K7.
37. K.L.R. Jansen. A review of the non-medical use of ketamine: use,
users and consequences. J. Psychoactive Drugs. 32(4): 419-433
(2000).
38. T. Chang and A.J. Glazko. Biotransformation and disposition of ke-
tamine. Int. AnesthesioL Clin. 12(2): 157-177 (1974).
39. C. Prys-Robert and C.C. Hug, Jr. Pharmocokinetics of Anaesthesia.
Blackwell Scientific Publications, London, U.K., 1984, pp.
235-245.
40. I.S. Grant and W.S. Nimmo. Ketamine disposition in children and
adults. Br. J. Anaesth. 55(11): 1107-1111 (1983).
41. M. Wood and A.J. Wood. Drugs and Anesthesia: Pharmacology for
Anesthesiologists. Williams & Wilkins, Baltimore, MD, 1990, pp
193-196.
42. D.A. Hass and D.G. Harper. Ketamine: a review of its pharmaco-
logic properties and use in ambulatory anesthesia. Anesth. Prog.
39:61-68 (1992).
43. I.S. Grant, W.S. Nimmo, and J.A. Clements. Pharmacokinetics and
analgesics effects of I.M. and oral ketamine. Br. J. Anaesth. 53:
805-810 (1981).