Theophylline and Dyphylline Levels in Serum by Liquid Chromatography

Abstract

Measurement of theophylline levels by UV spectrophotometric techniques is hindered by interferences from barbiturates and caffeine, and thermal lability of the drug necessitates derivatization if gas chromatography is to be used. Because of these factors, a liquid chromatographic method was developed which allows separation of the underivatized drug from interfering compounds, and quantitation of the theophylline in a single operation. The drug-containing fraction can be readily collected and subjected to mass spectral examination if there is any question as to its identity. The latter feature has particular significance in medico-legal cases.