A Simple HPLC-UV Method for the Quantification of Theophylline in Rabbit Plasma and its Pharmacokinetic Application

A simple, precise and accurate high-performance liquid chromatography-ultraviolet method was developed and validated for the quantification of theophylline in rabbit plasma using hydroxyethyl theophylline as an internal standard. Separation was performed on Waters (R) C-18 column (mu Bondapak (TM) 5 mu m, 150 x 3.9 mm) using a mobile phase consisting of water-acetonitrile (96:4 v/v) at a flow rate of 1 mL/min. Validation of the method was performed in order to demonstrate its selectivity, linearity, precision, accuracy and stability. The calibration curves of theophylline were linear over a concentration range of 0.1-25 mu g/mL. The within-and between-day coefficient of variation (CV) were <10%. The extraction recoveries of theophylline at the three levels of quality control samples were 63.1, 69.4 and 69.7%. The method was rapid with retention time of theophylline and the internal standard observed at similar to 5.2 and 6.5 min, respectively. The developed method was applied successfully for studying the pharmacokinetics of theophylline in rabbits.