A convenient, rapid and sensitive method for determination of ester derivative of 7-theophyllineacetic acid with propylene glycol in rabbit serum was developed. The procedure involved liquid-liquid extraction of the compound from matrix with chloroform:isopropanol (1:1), followed by RP-HPLC using LiChrosorb RP-8, 250 mm x 4.6 mm, 5 μm column and UV detection at 274 nm. The elution was achieved isocratically with a mobile phase consisted of methanol:water:tetrahydrofuran:o-phosphoric acid (42:55:2.5:0.5 v/v/v/v). 8-Bromotheophylline was applied as suitable internal standard. The assay was validated and found to be accurate, precise and specific. The calibration curve was linear over the concentration range of 5 to 50 mg/ml with r2 values greater than 0.99. The reported method was successfully employed for a preliminary pharmacokinetic study of the ester in rabbits. The twocompartmental pharmacokinetic model was used to fit the ester serum concentration-time curve. 7- Theophyllinylacetyloxyglycol was rapidly absorbed after oral administration. Maximum serum concentration was 35.60 ± 3.01 μg/ml that occurred at 2 h post-dosing.