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CLINICAL TOXICOLOGY
AUGUST 2012
CHIRAL SEPARATION
A SUPPLEMENTARY TEST SERVICE TO IDENTIFY
THE SOURCE OF METHAMPHETAMINE USE
Positive test result for methamphetamine in
urinary samples always raises a red flag for illicit
methamphetamine use in patients. A common
question ensued is, "What is the source of
methamphetamine?" (e.g., from street drugs or
prescription drugs), since several prescription
drugs and one over-the-counter inhaler can
either
contain
or
be
converted
to
methamphetamine.
Methamphetamine
is
naturally
chiral.
Two
isomers
of
methamphetamine, l and d-methamphetamine,
exhibit similar pharmacokinetic, but totally
different, pharmacological properties; with dmethamphetamine having psychoactive property
and abuse liability and l-methamphetamine
having minimal psychostimulatvie effect. With
known information for chiral composition in
different settings, a d/l isomer ratio would
greatly facilitate physicians’ judgment on the
source of methamphetamine. American Clinical
Solutions, in collaboration with NMS Labs, is
excited to present a novel methamphetamine
chiral resolution service based on a GC/MS
method. As a supplementary test service to
UPLC/MS quantitation, chiral separation is
capable of separating l-methamphetamine from
its d-isomer and generating a report for the ratio
of d versus l-isomer. Therefore, after UPLC/MS
quantitation of methamphetamine (both l and disomers) in a sample, a positive sample can be
further tested by GC/MS to determine the d/l
isomer ratio.
If a d/l ratio is equal to or less than 13%, it would
suggest that methamphetamine is predominantly l
isomer and therefore, it most likely comes from a
Vicks inhaler and Selegiline. A d/l ratio greater than
13% would highly suggest the use of schedule II
psychostimulants. Next, a review of the patient’s
prescription history would further reveal whether dmethamphetamine is converted from legal
prescription drugs or from illicit drug abuse. So far,
prescription drugs having been reported as a
precursor
to
d-methamphetamine
are
benzphetamine,
and
dimethylamphetamine,
famprofazone, fencamine, and fufenorex. For a
patient without prescription history for these drugs, it
would
highly suggest
an
illicit
use of
methamphetamine.
Methamphetamine positive (≥ 100 ng/ml)
Chiral separation for d/l ratio*
d/l ratio  13%
d/l ratio  13%
Vicks inhaler, With prescription:
Without prescription:
Selegiline
benzphetamine
Highly suggest from
dimethylamphetamine
illicit source
famprofazone
fencamine
fufenorex
Urine and Oral Fluid Confirmatory Drug Testing Laboratory - Support pain management - Monitor compliance - Identify undisclosed medications
Cheng Fang, MD., PH D., DABT | [email protected]
721 Cortaro Dr, Sun City Center, FL 33573 | T 866-762-8379 | F 813-634-4538