Determination of theophylline in serum by HPLC assay and study its pharmacoki- netics in Beagle's

AIM To develop a HPLC method for the determination of theophylline in serum and to investigate its pharmacokinetic characteristics in Beagle's.METHODS Serum samples (using caffeine as internal standard) were sed- imented by 15% perchloric acid and then detected by UV detector at (275±2)nm with Shim-pack VP-ODS C_(18)(150 mm×4.6 mm,5μm) and CH_3OH:CH_3COOH(1%):trolamine solution (24:76:0.15) as mobile phase at a flow rate of 1 mL·min~(-1);the serum concentration was detected by HPLC with the column temperature of 25℃.RESULTS The linear range was 0.1-25 mg·L~(-1).The detectable concentration was 25μg·L~(-1).The method recovery was more than 95%.Both the inter-and intra-day precision (RSD) was less than 5.0%.CONCLUSION The method provides a sta- ble and reliable method for pharmacokinetic studies after inhaling aminophylline as well as determining concentration of theophylline in serum.