AIM: To establish HPLC method for the determination of etodolac and to study
pharmacokinetics of etodolac in rats. METHODS:
Etodolac and internal standard (oxaprozin) were analyzed on C 18 column with an acetonitrile : water: triethylamine (16∶84∶0.002) mobile phase at 1.0 mL·min -1 flow rate. The UV detector was set at 280 nm. Rats' blood samples were collected before and at 5, 10, 20, 30 min and 1, 3, 6, 12, 24, 48, 72 h after treatment of once 20 mg·kg -1 dose of etodolac and
pharmacokinetic parameters were calculated. RESULTS: The retention time of etodolac and internal standard were 5.28 min and 6.80 min, respectively. The calibration curve was linear in the range of 1.0～100.0 mg·L -1 ( r = 0.9999, n = 7). The extraction recovery was between 73.4% and 80.5%, and the methodological recovery was between 97.3% and 106.0%. The intra day RSD and inter day RSD were less than 4% and 8%, respectively. The pharmacokinetic parameters of etodolac were 0.28 h± 0.13 h for T max ; 69 mg·L -1 ±5 mg·L -1 for C max ; 16.9 h±2.1 h for T 1/2; 2314 mg·h·L -1 ±328 mg·h·L -1 for AUC. CONCLUSION: This method is simple, sensitive, as well as rapid, and is suitable for application in pharmacokinetic study of etodolac.