Methods and Results of Barbital Research

We described 1 a colorimetric test for barbiturates and the rate of excretion of barbital determined by this test. We here report on (a) urinary elimination, (b) fate in the blood, (c) presence in organs of barbiturates, and (d) on the clinical application of this test.

The progress in these studies was made possible by the colorimetric test and by improved methods of extraction of barbiturates, consisting of shaking urine (alkalinized), oxalated whole blood, plasma or spinal fluid with equal volumes of 10% copper sulphate solution, filtering, acidulating the filtrate with dilute sulphuric acid and shaking the filtrate with 10 volumes of chloroform. The chloroform extract may be concentrated on water bath. Ground organs, before they are shaken with copper sulphate must be liquefied, either by 3% HCl and pepsin, or by mixing thoroughly with 5% KOH. Heating must be excluded in these procedures. The acid-pepsin treated organs must be alkalinized before shaking with copper sulphate.

Results. (a) Urinary Excretion. The excretion of barbital was studied in normal dogs (70-300 mg. per kg., intravenously), in the cat (250 mg. per kg., intravenously), humans (30 grains total, by mouth) and in the fowl (225 mg. per kg., intravenously). Normal dogs (8), cat (1), and humans (2) excreted from 42% to 89% of barbital during 7 days (more than 1/2 of the dose usually in the first 48 hr.), from 13% to 16% of phenobarbital (2 dogs, 100 mg. per kg., intravenously) and about 40% each of neonal (1 dog, 60 mg. per kg., intravenously) and dial (1 dog, 80 mg. per kg., intravenously) and only small amounts of pernoston and amytal (3 dogs). Diuretic treatment (intravenous injections of 50 cc. of 10% glucose solution per kg. of body weight) did not increase the percentage excretion of barbiturates (from 50% to 92% for barbital (5 dogs), 16% for phenobarbital (1 dog), and 31% dial (1 dog, 100 mg. per kg., intravenously).