Spectrophotometric Determination of Piroxicam and Tenoxicam in Pharmaceutical Preparations Using Uranyl Acetate as a Chromogenic Agent

New simple spectrophotometric methods for the determination of piroxicam, and tenoxicam in pharmaceutical preparations based on the reaction of piroxicam, and tenoxicam with uranyl acetate have been developed. The reagent forms yellow 1:2 complexes with piroxicam and tenoxicam in alcoholic medium. The complexes are stable for more than 24 hrs. The coloured species have absorption maxima at 395 and 435 nm, with molar absorptivities of 3.8 × 10 3 and 0.21 × 10 3 1mole −1 cm −1 , and the mean percentage recoveries for authentic samples were 99.11±0.79, 98.78 ± 0.62 for piroxicam and tenoxicam, respectively. The site of chelation is given, and discussed.