Introduction: A rapid and sensitive ultra high performance liquid chromatography (UPLC)
method was developed and validated for the determination of doxofylline and its metabolite theophylline
in rat plasma using caffeine as an internal standard.
Methods: The analysis was performed on a Waters Acquity C18 column (2.1 mm*50 mm, 1.7 µm) with
detection wavelength setting at 273 nm. The mobile phase was acetonitrile and water in gradient elution
at a flow-rate of 0.2 ml/min.
Results: The calibration curves were linear in the range of 0.3~500 µg•ml-1 for doxofylline and 0.5~20
µg•ml-1 for theophylline, respectively, the intra-day and inter-day precision (RSD) values were below 6%,
the relative recovery was from 96.83% to 101.38%, and the extraction recovery was above 85.00%.
Conclusion: This developed method was successfully used for the determination of doxofylline and theophylline
in rat plasma for pharmacokinetic study.