A new HPLC method for the determination of etodolac in plasma and its application in bioavailability and pharmacokinetic studies

A simple, rapid, specific and sensitive reversed-phase high performance liquid chromatographic method for the determination of etodolac in plasma has been developed. Each analysis took no more than 4.5 min and the detection limit was 0.5 μg mL -1 . The developed method was applied for determination of the bioavailability and pharmacokinetic parameters of etodolac in human plasma after its administration by two different routes. The obtained pharmacokinetic parameters include AUC, t max, c max and t 1/2. Peak plasma concentrations were 6.2 and 20.6 μg mL -1 following rectal and oral administration of the drug, respectively. The bioavailability of suppositories, compared to capsules, was found to be 66.0%. The developed method possessed enough specificity and sensitivity required to monitor etodolac in human plasma. In addition to etodolac, the method could be used for the detection of five other NSAIDs, namely, diclofenac, sulindac, piroxicam, indomethacin and ketoprofen.