Cannabinoid Assays in Humans, 7 - Archives - National Institute on

133 Pages·2002·2.28 MB·English

CANNABINOID ASSAYS
IN HUMANS
Editor
ROBERT E. WILLETTE, PH.D.
Division of Research
National Institute on Drug Abuse
May 1976
NIDA Research Monograph 7
National Institute on Drug Abuse
11400 Rockville Pike
Rockville, Maryland 20852
U.S. Department of Health, Education, and Welfare
Public Health Service
Alcohol, Drug Abuse, and Mental Health Administration
The NIDA Research Monograph series is prepared by the
Research Division of the National Institute on Drug Abuse. Its
primary objective is to provide critical reviews of research problem
areas and techniques, the content of state-of-the-art conferences,
integrative research reviews and significant original research. Its
dual publication emphasis is rapid and targeted dissemination to
the scientific and professional comunity.
EDITORIAL ADVISORY BOARD
Avram Goldstein, M.D. Addiction Research Foundation
Palo Alto, California
Jerome Jaffe, M.D. College of Physicians and Surgeons
Columbia University, New York
Reese T Jones, M.D. Langley Porter Neuropsychiatric
Institute
University of California
San Francisco, California
William McGlothlin, Ph.D. Department of Psychology, UCLA
Los Angeles, California
Jack Mendelson, M.D. Alcohol and Drug Abuse Research
Center
Harvard Medical School
McLean Hospital
Belmont, Massachusetts
Helen Nowlis, Ph.D. Office of Drug Education, DHEW
Washington, D.C.
Lee Robins, Ph.D. Washington University School of
Medicine
St. Louis, Missouri
NIDA RESEARCH MONOGRAPH series
Robert DuPont, M.D. DIRECTOR, NIDA
William Pollin, M.D. DIRECTOR, NIDA RESEARCH DIVISION
Robert C. Petersen, Ph.D. EDITOR-IN-CHIEF
Eunice L. Corfman, M.A. MANAGING EDITOR
Rockwall Building 11400 Rockville Pike Rockville, Maryland, 20852
CANNABINOID ASSAYS
IN HUMANS
Thanks are due the people of Macro Systems, Inc.,
who capably organized and smoothly coordinated
the conference, held February 24th and 25th, 1976,
under NIDA contract #271-75-1139, from which the
papers in this monograph are derived.
DHEW publication number (ADM) 76-339
Library of Congress catalog card number 76-15843
This document is for sale by National Technical Information Service
Springfield Va. 22161
Stock Order #PB 251 905; Papercopy: $6.00; Microfiche: $2.25
iv
FOREWORD
This monograph describes ways of determining
the levels of cannabinoids in the human body
after smoking marihuana. Investigations of a
number of serious social and health problems
have had to wait for the refinements of these
techniques.
Chief among these concerns is the effect of
marihuana smoking on driving. That investi-
gation along with others can now be undertaken
with an expectation of far more precise find-
ings than was formerly possible. We now have
the means not only of detecting cannabinoids,
but also of determining in what quantity they
are present. Thus, we can begin to establish
specific correlations between cannabinoid levels
and driving impairment. This information is
necessary in order to build marihuana into the
highway safety campaign now largely restricted
to alcohol.
These assay techniques will be useful tools
for a range of other problems including simple
screening procedures, epidemiological studies,
forensic toxicology, as well as for more funda-
mental pharmacokinetic and pharmacological re-
search. The developments in method and instru-
mentation described here occur at a crucial
juncture for drug abuse research, as we strive
to assess the impact of marihuana on our culture.
Robert L. DuPont, M.D.
Director
National Institute on Drug Abuse
v

PREFACE
For the past several years, there has been an
increasing demand for qualitative and quantitative
assays for identifying and measuring the consti-
tuents of marihuana in the human body. This demand
is prompted by the need for such assays in several
research investigations that are attempting to im-
prove our understanding of how this complex drug
affects the body. In addition to these more
fundamental issues, there is a growing feeling that
suitable analytical methods will be required for
determining the presence of cannabinoids in drivers
suspected of being under the influence of the drug.
We have now reached a stage in the search for and
development of such methods that many of them can
now be employed in a routine manner. As we gain in
experience and confidence with these methods, their
validity will become increasingly better established
and their applicability to critical decisions more
acceptable. It will be apparent upon reviewing the
procedures described herein that some were designed
for or are by their complexity only suited for re-
search purposes or in validating other methods.
Others described are more amenable to routine
screening or survey applications.
The road to acceptable methods has been long and
arduous. Early attempts continued to suffer from
lack of adequate sensitivity. It was eventually
learned, as the studies on the composition of
marihuana and the metabolism of its constituents
progressed, that the problem of detecting any
specific cannabinoid in the body after use would
be an extremely difficult task. The primary active
constituent, delta-9-tetrahydrocannabinol (THC) is
rapidly distributed and metabolized in the body,
making its quantification a major challenge. It is
now very gratifying to be able to present a collec-
tion of manuscripts that delineate the tremendous
progress that has been made over the past few years.
vii
The methods described are grouped together under
three major headings. The first are based on the
increasingly used immunoassay techniques. In gen-
eral, immunoassays offer speed and sensitivity and
are very amenable to the screening of large numbers
of samples. They often suffer from lack of speci-
ficity, but this is often acceptable if they cross
react only with metabolites of the target drug and
no other drug. The four methods described are at
various stages of development and refinement, and
some are being employed in various research studies.
Methods of the second group are based on the older
technology of chromatography, but are applied in
rigorous and innovative ways to provide the degree
of sensitivity required to measure the low levels
of drugs and metabolites. Two different approaches
were taken to reduce the background interference.
Using a conventional gas chromatograph, Dr. Garrett
employed a high pressure liquid chromatograph (HPLC)
to "clean-up" the sample. The dual-column instru-
ment designed by Dr. Fenimore reduces the amount of
effort required for sample preparation. As the
technology in HPLC progresses, this method is be-
coming extremely popular, offering the ability to
separate difficult mixtures at low temperatures.
The effort described here is moving forward and
parallels similar efforts that are being carried
out by Dr. Valentine, in an outgrowth of his pro-
ject's mass spectroscopic method.
The last group of methods all employ the mass
spectrometer as the detector for identifying and
quantifying the cannabinoids. Rapid advances in
the development of mass spectroscopy have made it
the method of choice in terms of sensitivity and
specificity. Because of its present size, cost,
and complexity, it is not ideal for routine appli-
cation to routine screening. It is, however, being
used for the routine validation of other methods
and to confirm the presence of cannabinoids in
samples found positive by less specific screening
methods, like the immunoassays. The six papers
included represent some of the most outstanding
work done in the field of mass spectroscopic
analysis. Since Dr. Agurell first published his
method in 1973, tremendous strides have been made
by him and the others included in this monograph.
viii
We now feel very confident in our ability to get on
with many of the critical studies that have awaited
these methods.
This collection of papers does not signal the end
of the road in the development of suitable methods
for quantifying cannabinoids in the body. As our
understanding of the effects of marihuana pro-
gresses, so must the methods used in studying it.
We now have methods to study the effects of mari-
huana on driving, and if the evidence indicates
that it poses a significant hazard, then a simple-
perhaps roadside- test may be required. Other
examples could be cited, but it is sufficient to
end with the recognition of a notable achievement
in this difficult area of research and a sense of
satisfaction that our perseverance is paying off.
Robert E. Willette, Ph.D.
Uivision of Research
National Institute on Drug Abuse
April 1976
i x