familiar with the drugs ethotoin - Clinical Chemistry

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