A New RP-HPLC Method for Simultaneous Estimation of Etophylline and Theophylline in Tablets

A simple, accurate, economical and reproducible RP-HPLC method for simultaneous estimation of two component drug mixture of Etophylline (ETO) and Theophylline (THEO) in combined tablet dosage form have been developed. The reversed phase chromatography system was used with C18 column and the detection was made at 241 nm in the UV region. Mobile phase consisted of methanol: phosphate buffer (75:25) at a flow rate of 1 ml/min. The calibration curve was linear in the concentration range of 50–250 μg/ml for ETO and 15–75 μg/ml for THEO. The retention time of ETO and THEO was 2.78 and 5.08 min respectively. The developed method was validated for accuracy, precision, linearity, limit of detection and limit of quantification.