Sensitive liquid chromatographic assay for the simultaneous determination of ibuprofen and its prodrug, ibuprofen eugenol ester, in rat plasma.

A rapid, sensitive, and specific reverse-phase high-performance liquid chromatography (HPLC) method was developed to quantitate ibuprofen (IBU) and its prodrug, ibuprofen eugenol ester (IEE), simultaneously in rat plasma. IBU, IEE, and the internal standard glycryrrhetic acid (GA) were detected by UV absorption at 230 nm. Extraction recoveries for all compounds ranged between 82.6% and 96.2%. Retention times of IBU, IEE, and GA were 5.62, 15.98, and 18.05 min, respectively. Calibration plots were linear over the range of 0.64 to 64 microg/ml for IBU, and 0.16 to 80 microg/ml for IEE. The limit of quantitation was 0.64 microg/ml for IBU and 0.16 microg/ml for IEE. The intra- and interday variations were less than 10% and accuracy was greater than 90%. The results showed that the established method is reproducible and sensitive and applicable to plasma samples collected from rats administered IBU and IEE intravenously.