Abstract
1. Methods are described for the estimation of Pentothal and a metabolite of Pentothal in biological fluids and tissues. The method for Pentothal is specific in that metabolic products of the drug are not included in the measurement.
2. A major step in the metabolism of Pentothal after its intravenous administration to man is oxidation on one of its alkyl side chains to yield a carboxylic acid. This compound, which has been isolated in pure form, has identical ultraviolet properties with that of the parent drug. It has little if any anesthetic activity.
3. Although Pentothal is transformed almost completely in the body, the rate of this transformation is slow in man, about 15 per cent per hour, and even slower in dogs. The rapid decline in plasma levels and quick recovery following a single intravenous dose is probably due to the drug leaving the body fluids and being deposited in the fat.
4. There is a marked decrease in plasma levels of Pentothal in dogs as the pH is lowered by carbon dioxide inhalation.
Footnotes
- Received October 10, 1949.