Simple and Sensitive High-Performance Liquid Chromatographic Method for Determination of Transdermally Applied Flurbiprofen in Rat Plasma and Excised Skin Samples

A simple reversed-phase HPLC method has been developed for determination of flurbiprofen in rat plasma, excised skin extract, and transdermal patch formulations. The mobile phase was methanol–1% (v/v) phosphoric acid in water, 80:20 (v/v), at a flow rate of 0.5 mL min^-1; ibuprofen was used as internal standard. Flurbiprofen and ibuprofen was detected by UV absorption at 254 nm and 220 nm, respectively. The limit of quantitation was 0.1 µg mL^-1. The response was linearly dependent on concentration in the range 0.1–10 µg mL^-1, and accuracy and reproducibility were good. At these concentrations intraday and interday assay variability were below 8%. Recovery of flurbiprofen was greater than 94% over the linear range of calibration plot.