A sequential injection method for the determination of piroxicam in pharmaceutical formulations using europium sensitized fluorescence.

A simple, selective and sensitive luminescence method for the assay of piroxicam (PX) in pharmaceutical formulation is developed. The method is based on the luminescence sensitization of europium (Eu(3+)) by complexation with PX. The signal for PX-EU is monitored at lambda(ex)=358nm and lambda(em)=615nm. Optimum conditions for the formation of the complex in methanol were 0.01M TRIS buffer and 0.2mM of Eu(3+) which allows the determination of 100-2000ppb of pX in batch method and 100-1000ppb with limit of detection (LOD) = 23.0ppb using sequential injection analysis (SIA). The relative standard deviations of the method range between 2 and 3% indicating excellent reproducibility of the method. The proposed method was successfully applied for he assay of PX in pharmaceutical formulations (Feldene capsules and tablets). Average recoveries of 101.0+/-0.3 and 98.8+/-2.7% were obtained for capsules in methanol using batch and sequential injection (SI) methods, respectively.