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Published:
Journal of Analytical Toxicology,
ISSN 0146-4760,
Volume 27, Number 3, April 2003,
pp. 149-155
TECHNICAL NOTE: Ofloxacin as a Reference Marker in Hair
of Various Colors
Diana G. Wilkins[1], Atsuhiro Mizuno[2], Chad R.
Borges[1],
Matthew H. Slawson[1],
and Douglas E. Rollins[1]
[1]Center for Human Toxicology, Department of Pharmacology and Toxicology, Room
490 Biomedical Polymers Research Building, University of Utah, 20 South 2030
East, Salt Lake City, Utah 84112 and
[2]Phase 1 and Clinical Pharmacology Department,
GlaxoSmithkline K.K., 6-15, Sendagaya 4-chome, Shibuyaku, Tokyo 151-8566, Japan
It has been proposed that
administration of a reliable marker substance to human subjects may enhance
the ability to
identify drug use and treatment compliance in drug treatment programs. The
goal of this study was to determine if an oral dose of the antibiotic ofloxacin
(OFLX) could be used as a "marker" substance to establish reference
points with respect to time in hair of various colors. Male and female subjects
(n = 32) between 18 and 40 years of age received 800 mg of OFLX as a divided
oral dose on a single day. Subjects were restricted from cutting their hair
or performing chemical treatments. Hair was collected (by cutting) before,
and at weeks 4, 5, 6, and 7 after drug administration. Subjects were classified
as having black (n = 5), brown (n = 13), blonde (n = 8), or red (n = 6) hair.
Hair was segmented into 3.0-cm segments prior to digestion, extraction, and
analysis by high-pressure liquid chromatography (HPLC). At 7 weeks, the mean
OLFX concentrations (± 1 SD) in the first 3.0 cm of hair closest to
the scalp were as follows: 30.6 ± 8.5 ng/mg (black), 6.0 ± 1.8
ng/mg (brown), 3.5 ± 1.6 ng/mg (blonde), and 1.4 ± 0.3 ng/mg
(red). A similar pattern was found in hair collected at weeks 4–6.
Quantitative eumelanin (EUM) hair concentrations for each subject were also
determined for each subject via HPLC. A strong relationship between OFLX
concentration at 7 weeks and EUM was noted (r2 adjusted = 0.728; p < 0.001).
In six subjects, we also determined the intrasubject variability of OFLX
incorporation into individual hair strands. Four strands from each subject
were segmented into 2-mm segments and analyzed. OFLX appeared in segments
#1–#10 at week 5 (the first centimeter of hair). OFLX appeared in segments
#2–#20 at week 7 (the first and second centimeter of hair). The maximum
OFLX concentration (the "band" of drug) and location was then
determined for each strand. The maximum OFLX concentration was measured in
segments #2–#5 at week 5 for all subjects (within the first centimeter
of hair length). The maximum OFLX concentration was measured in segments
#3–#8 at week 7 (within the first and second centimeter of hair). This
was consistent with a growth rate of less than 1.0 cm/month, although considerable
intersubject variability was found. No significant axial diffusion of OFLX
along the hair shaft beyond the first 3.0 cm of hair was noted. Despite a
strong effect of hair color, these data suggest that OFLX may be a suitable
marker substance for hair, allowing a subject to serve as their own "control".
Future studies will explore whether drug use, treatment compliance, or recidivism
in clinical drug-abuse studies can be determined with the aid of OFLX. Reproduction
of editorial content of this journal is prohibited without publisher’s
permission.
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