A Direct Injection HPLC Procedure for the Quantitation of Theophylline in Blood and Saliva

A rapid and sensitive method for determination of theophylline in serum or saliva specimens utilizing high-pressure liquid chromatography (HPLC) is described. The analysis is performed on 2 µL of specimen which does not require chemical manipulation prior to analysis. Studies comparing spiked aqueous samples of theophylline to spiked serum samples indicate that total theophylline is determined by this procedure. The method was used to compare capillary and venous blood and saliva theophylline concentration in healthy adult volunteers after administration of 200 mg theophylline every six hours for two days. The small sample size required makes the determination ideal for neonatal and pediatric use.