Gas-Chromatographic Determination of Theophylline in Human Serum and Saliva

Abstract

Abstract We report a gas-chromatographic procedure for routine determination of the bronchodilator, theophylline (1,3-dimethylxanthine), in serum and saliva. Volatile butyl derivatives for gas chromatography were prepared by the method of Greeley [Clln. Chem. 20, 192 (1974)], with butyliodide as the alkylating agent. Substances that interfere in the classical determination of theophylline, such as theobromine (3,7-dimethylxanthine) and phenobarbital, are well separated from theophylline by the gas-chromatographic procedure and can be quantitated if desired. It is possible to determine 1 µg of theophylline in 1 ml of serum or saliva. Between-run precision for 15 µg/ml samples was 5.3%. This determination is useful in assessing patient compliance with medication instructions and in adjusting dosage schedules of theophylline in patients attending a pediatric allergy clinic.