... L. G., âCK-NACâ-Complete ac- tivation? GUn. Ghem. 23, 772 (1977). Let- ter. 5. Bostick, W. D., and Mrochek, .... it settle by gravity, and gently replace the disc.
4. Morin, tivation? ter.
L. G., “CK-NAC”-Complete GUn. Ghem. 23, 772 (1977).
acLet-
5. Bostick,
W. D., and Mrochek, J. E., Evalfast analyzer of a chemical activation procedure for creatine kinase MB isoenzyme. GUn. Ghem. 23 (1977), in press, September.
uation on the centrifugal
Leo G. Morin VA Hospital (Atlanta) Decatur, Ga. 30033
tamine by gas chromatographyasthe N(N’-trifluoroacetyl-L-prolyl) derivatives (2). The extraction and derivatization procedures were similar to those described by Gal (3) in preparing related diastereomers. Both specimens were positive for (-)-methamphetamine, with no detectable (+)-isomer. The implications of this fmding are of course considerable, particularly with
regard
to
sence
forensic specimens. In the ab-
of an isomer
fendant urine
identification,
with methamphetamine
could
(-)-isomer
claim
a de-
in his
of the legitimate
use
even if he was actually using
or racemic metham-
Literature Disagreement as to Identity of Nirvanol#{174}
contraband phetamine.
To the Editor: Those of your readers who are interested
been unfairly victimized because norance of this phenomenon.
in anticonvulsant-drug
bringing this case history to the atten-
analyses
will be
mephenytoin (Mesantoin#{174}, 5-ethyl-3methyl-5-phenylhydantoin). They will also be familiar with the name Nirva-
nol#{174}. Unfortunately, a dreadful state of confusion exists among various authoris ethotoin
Nirvanol
or the N-demethylated metabolite mephenytoin: 5-ethyl-5-phenylhydantoin. I suggest
the easiest solution completelydrop the term Nirvanol
of
is to from
our vocabulary.
other
hand,
one of ig-
of
tion of other laboratories involved in mass-screening programs and will publish full experimental details of the analytical method in due course. References 1. Solomon, M.D., A study of codeine metabolism. Gum. Toxicol. 7, 255 (1974). 2. Halpern, B., and Westley, J. W., Highsensitivity optical resolution of aniines by gas chromatography. Ghem. Gommun. 34 (1966). 3. Gal, J., Stereochemistry amphetamine: Use of
of metabolism (-)-a-methoxy-a-
of
66, 169 (1977).
Malcolm D. Solomon James A. Wright
V5Z 1M9
We have previously reported circumstances under which it is possible for a legitimate codeine user to be suspected of heroin abuse (1) and we now wish to describe a case in which the user of a relatively innocuous over-the-counter product, viz., Vick’s Inhaler (Vick
volumes
are
not
Time for completion: As outlined in the package insert, the test is very time consuming,especially when itis“negative for free bilirubin.” We recommend
immediately setting up the four columns (positive control, patient’s serum, paserum
plus 25 mg of unconju-
gated bilirubin per liter, and patient’s serum plus 50 mg of unconjugated bilirubin per liter). In this way, the entire test can be completed in 25-30 mm (compared with an hour or more when the residual binding capacity exceeds 50
mg/liter). Cost: The cost of running the ‘complete test (four columns) is excessive,
because the kit currently costs $18.00/b columns, or $7.20/test in reagents alone. There are several ways one can reduce this. If the diazo tablet/distilled water stepisreplacedby 0.50ml ofdiazosolution (a total and direct bilirubin should be run on each sample), the column can be washed with 5 ml of 0.1
mol/liter NaOH, followed by about 5 ml ofde-ionizedH20 and finally with 2-3 ml ofphosphatebuffer. Itisstoredwith 1 ml ofbufferon top.The columns can be used two or three times in this fashion, at which time the flow through
usually becomes slow and irregular.
St. Calif.
this
94103
point,
one can remove
them
At
the porous stir well, let
discoverlying the Sephadex, it settle by gravity, and gently replace gray, but still works well.) One can,after
The Routine Use of Sephadex to Estimate “Free” Bilirubin and the Residual Serum Blllrubin Binding Capacity
cycles, repack the columns with fresh Sephadex (Pharmacia Fine Chemicals, Inc., Piscataway, N. J.
several
08854), or prepare
To the Editor:
The use of Sephadex G-25 gel filtration as a means of estimating the presence of “free”
pected of ingesting the widely-abused anorexigenic and stimulant, (+)A male subject in a surveillance program, whose urine was repeatedly positive for methamphetamine, vehemently denied any use of the drug. However, he
bin binding capacity is rather well accepted as a valuable aid to the clinician in preventing bilirubin encephalopathy (1-3). The test is now marketed in kit form (Ames Co.,Elkhart,Ind.46514), and has been shown to be clinically reliable (4). Our experience supports their
did claim heavy use of the Inhaler,
a
study.
product containing the sympathomimetic (-)-methamphetamine, for
a
comings
methamphetamine.
bilirubin
There
and the residual
are, however, to the test,
several
biliru-
short-
as marketed,
that
sinus disorder. Armed with this knowledge, we analyzed two of the urine specimens in
can be improved. These are as follows:
question
for free bilirubin,”
Sample “positive
8, 1977
volume: for free
new columns,
using
other supports such as 3- or 5-ml sy-
Chemical Co., Wilton, Conn.), was sus-
1504 CLINICALCHEMISTRY,Vol. 23, No.
reagent
changed.
the disc. (The Sephadex becomes a little
To the Editor:
and (-)-methamphe-
other
Hine Laboratory
False-Positive for (+ )-Methamphetamine
(+)-
rubin is also decreased to 50 jl, but the
357 Tehama San Francisco,
for
have satisfactorily adapted the procedure to 50 l of serum. The added bili-
tient’s
We are grateful for the opportunity
Sci.
Division of Clinical Chemistry Vancouver General Hospital B.C., Canada,
the
(trifluoromethyl)phenylacetyl chloride for GLC resolution of chiral amines. J. Pharm.
W. Godolphin
Vancouver,
On
wonders how many sinus sufferers have
familiar with the drugs ethotoin (Peganone#{174}, 3-ethyl-5-phenylhydantoin) and
ities as to whether
(+)-
required. However, results for most patients will be negative. One of the real values of the test is the estimation of the residual serum bilirubin binding capacity. When this is >50 mg/liter, as most cases are, 300 il of serum is needed. This, of course, can be a real problem when one must repeat it at intervals. We
For
bilirubin”
100
a report
of
or “negative
l of serum is
ringes, The
etc.
bilirubin standard (Sigma Chemical Co., St. Louis, Mo. 63178) is readily prepared by dissolving exactly 1.0 mg in 4 ml of chloroform. Of this so-
lution,
200 zl (50 sg of bilirubin)
is
added to the inside of the screw cap of a 15-ml graduated conical centrifuge tube (Falcon, Division of Becton, Dickinson
and Co., Oxnard, Calif.
93030).
Each
cap, when air dried in the dark at room temperature and reconstituted with 2 ml of Na2CO3, results in a 25 mg/liter solution.
An important point should be emphasized with respect to conjugated bilirubin. The package insert cautions that when the direct bilirubin exceeds 20