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22
Figure 25
The optical isomers of TFA-fenfluramine and its metabolite are
well resolved on the Rt-
β
DEXcst column.
Figure 26
The Rt-
β
DEXcst column can resolve the enantiomers of
common barbiturates.
20
min. 15
25
30
35
40
20
min. 10
30
50
40
Figure 27
The Rt-
β
DEXcst column simultaneously resolves the enantiomers of
TFA-amphetamine and TFA-methamphetamine.
12
min. 10
14 16 18 20 22 24
30m, 0.32mm ID, 0.25µm
Rt-
β
DEXcst (cat.# 13102);
Oven temp.:
60°C (hold 1min.) to
220°C@ 3°C/min.;
Carrier gas:
hydrogen; 80cm/sec. set @ 60°C;
Detector:
FID set @ 220°C.
30m, 0.32mm ID, 0.25µm
Rt-
β
DEXcst (cat.# 13102);
Oven temp.:
90°C (hold 1min.) to
200°C@ 2°C/min. (hold 3min.);
Carrier gas:
hydrogen; 80cm/sec. set
@ 60°C;
Detector:
FID set @ 220°C.
(+)-fenfluramine
(-)-fenfluramine
(+)-norfenfluramine
(-)-norfenfluramine
(+/-)-hexobarbital
(+/-)-mephobarbital
30m, 0.25mm ID, 0.25µmRt-
β
DEXcst (cat.# 13103);
Oven
temp.:
120°C (hold 1min.) to
175°C@ 1.5°C/min.;
Carrier gas:
helium; 25cm/sec. set @ 120°C;
Detector:
MSD set @ 220°C.
methamphetamine
amphetamine
DRUGS
○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○
Stereochemical properties of chiral
drugs have been found inmany in-
stances to be the controlling factor
concerning activity. One enantiomer
mayprovideabiological function.The
other may be inactive or exhibit an-
other functionality, which could re-
sult insideeffects. Insomecases,one
optical isomer may be harmful. The
FDA requires drugmanufacturers to
test the individual enantiomers of
new drugs for toxicity.
Fenfluramine
○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○
Fenfluramine isanappetite suppres-
sant to promote weight loss with
obese patients.
9
Although it is struc-
turally similar to amphetamines, it
differs somewhat pharmacologically.
Norfenfluramine is ametabolite that
is found in urine and serum of pa-
tients. The purpose of the chiral iso-
lations, like many analyses in the
pharmaceutical industry, isofpropri-
etary nature. The TFA derivatives of
both fenfluramine and norfenflur-
amine are separated into their enan-
tiomers on the Rt-
β
DEXcst column
(
Figure 25
).
Barbiturates
○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○
Mephobarbital and Hexobarbital are
barbiturates with sedative, hypnotic
and anticonvulsant properties.
10
Be-
cause psychological andphysical de-
pendencemay occurwith continuing
use, theyarecontrolledsubstances in
theU.S.Codeof FederalRegulations.
The optical isomers of these barbitu-
rates canbe simultaneously resolved
on an Rt-
β
DEXcst column (
Figure
26
).
Amphetamines
○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○
Dextroamphetamine (
d
-amphet-
amine),
d,l
-amphetamine, and
d
-
methamphetamine are sympathomi-
metic amines with central nervous
system stimulant activity.
11
They are
significant drugs of abuse in the
United States and are included
among the drugs to be tested under
(+)
(-)
(+) (-)
