Rapid determination of theophylline in human plasma by high-pressure liquid chromatography.

A rapid, specific, high-pressure liquid chromatographic method for the determination of theophylline in plasma was developed. The procedure is fast enough (21 min from receipt of blood to reporting value) to be used for emergency determinations. The sensitivity, precision, and accuracy are sufficient for routine monitoring of therapeutic levels in patients. The assay is specific enough to be valid in the presence of caffeine and theobromine. Metabolites of theophylline as well as a number of drugs do not interfere with the assay.