Assay of naproxen in rat serum by high-performance thin-layer chromatography/densitometry

A simple, sensitive, and reproducible high-performance thin-layer chromatog raphic method using densitometry is presented for the determination of napr oxen in rat serum, Only 0.1 mi, serum was used for extraction. Separations were performed on 10 x 10 cm plates coated with silica gel, with toluene-et hyl acetate-acetic acid (82 + 15 + 3) as the mobile phase. Benzophenone was used as the internal standard, Quantification was performed by densitometr y at 260 nm, The response for naproxen was linear (r = 0.992) over the rang e 2-100 mg/L, Method validation demonstrated good recoveries (92-96%), sens itivity (limit of quantitation, 1 mg/L), repeatability of sample applicatio n (4%), repeatability of the method (8%), and intermediate precision (5%), The procedure was applied to the quantitation of naproxen in rat serum.