Determination of some non –steroidal anti-inflammatory drugs through quenching the fluorescence of lanthanide Tris complex

Abstract

A new, simple and sensitive spectrofluorimetric method is developed for the determination of
Piroxicam (PX), Tenoxicam (TX) and Lornoxicam (LX) .The proposed method involves the formation
of complex with terbium (Tb3+) in the presence of Tris buffer. The quenching of terbium fluorescence
due to complex formation is monitored at λ em 540 nm after using λ ex 237 nm. A linear relationship is
found between the concentration of the studied drugs and the quenching of the fluorescence of
terbium-Tris complex. The optimum reaction conditions are studied and optimized .The proposed
method is applicable over the concentration range 1.509×10-6 – 1.509 × 10-5 M (0.5-5 μg mL -1), 2.96 ×
10-6 – 1.48 × 10-5 M (1-5 μg mL -1) and 1.34 × 10-6 – 1.34 ×10-5 M (0.5-5 μg mL -1) with mean
percentage recovery 99.66 ± 3.3, 100.79 ± 4.9 and 99.7±1.1 for PX, TX and LX respectively.The
Correlation Coefficient is 0.9983 (n=8), 0.9989 (n=5) and 0.9999 (n=6) with limit
of detection 0.2, 0.25 and 0.2 μg mL-1 for PX , TX and LX respectively. The proposed method is
applied successfully for the determination of the three drugs in their pharmaceutical formulations.The
results are compared favorably with those of official or reference methods.