Plasma pentobarbitone levels. Estimation by gas-liquid chromatography after clinical doses.

A simple and relatively quick method of estimating pentobarbitone in plasma samples is reported using an ether extraction and gas-liquid chromatography. Glutethimide was used as the internal standard and proved reliable. Reproducible results were obtained in plasma following 100 mg pentobarbitone given by mouth or intramuscular injection. Evaporation in a heating block at 37 degrees C and storage of samples at -20 degrees C prior to analysis is recommended.