SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

M14
CLOZAPINE DOSE-HAIR CONCENTRATION RELATIONSHIPS: EVALUATION OF
INPA TlENT AND OUTPA TlENT DATA
Robert Kronstrand*, Ingrid Nystrom, Markus Roman, and Martin Josefsson: National Board of Forensic
Medicine, Dep. Forensic Chemistry, Linkoping, Sweden
The aim of this work was to test the hypothesis that the concentration of clozapine in hair is dependent on
the dose administered. The hypothesis was tested both in an inpatient (N=22) and an outpatient (N=41)
population, with and without correction for hair pigmentation.
Samples were taken from the head and stored dark at room temperature until analyzed. Five cm of each hair
sample was analyzed. Briefly, the hair was cut into small pieces and weighed into a 10 mt screw-capped
tube. To approximately 25 mg of hair were added 0.5 mL of mobile phase (10:10:80 mixture of
acetonitrile:methanol:20mM formate buffer pH 3.0) and 25 /-ll of internal standard (2.0 Ilg/ml of d3­
mianserine) and the sample was incubated in a water bath (with orbital shaking) at 37 °C during 18 hours.
A 150-/-ll aliquot was transferred to an autosampler vial and 10 /-ll were injected into the chromatographic
system.
The LC-MS-MS analysis was performed on a Perkin Elmer Series 200 chromatography system consisting
of a Series 200 pump, Series 200 auto sampler, and a SCIEX API 2000 MS-MS instrument equipped with
an electrospray interface (Turbo Ion Spray). We used a 50x2.l mm Zorbax SB-Cyano analytical column
with 3-fJ.m particle size. For clozapine, two transitions, 327.11270.0 and 327.1/192.2, were monitored and
for d3-mianserine 268.31208.2 was monitored. All samples were also analyzed for melanin using
spectrophotometry (Iambda=550 nm) as previously described (Kronstrand et al. Clinical Chemistry 1999,
45:9, pp 1485). The daily doses ranged from 125 to 800 mgs.
The hair melanin concentrations ranged from 5 to 49 /-lg/mg and the clozapine concentrations ranged
between 1.1 to 37 nglmg. In the outpatient population a coefficient of determination of r=0.14 was achieved
when correlating the dose with the hair c10zapine concentration, as compared to 0.36 for the inpatient
population. When melanin was taken into account the coefficients were increased to 0.36 (out) and 0.62
(in), respectively. The results indicated that melanin influenced the incorporation of c10zapine into hair and
that the outpatients might have been less compliant than the inpatients, and thus obscuring the results. In
summary, it seems that the more controlled the dosing is, and the more factors that influence incorporation
are taken into consideration, the better the relationship between dose and hair concentration. Our
hypothesis was only confirmed under the certain circumstances of controlled dosing and melanin correction
(see figure), otherwise no correlation could be found between the dose and the hair c10zapine concentration.
Inpatient Dose vs CLZlMEL
1,6
1,2 •
r=O,62
01
• • •
• •
~ 0,8
c
0,4
0,0 I
100 300 500 700 900
mg/day
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