Adsorptive stripping voltammetric determination of the anti-inflammatory drug celecoxib in pharmaceutical formulation and human serum.

Celecoxib is a cyclooxygenase inhibitor, that has been recently and intensively prescribed as an anti-inflammatory drug in rheumatic osteoarthritis. A robust, highly reliable and reproducible square-wave (SW) adsorptive cathodic stripping voltammetric procedure was developed for the determination of celecoxib in pharmaceutical formulation and human serum. The analytical procedure was based on the reduction of the CN of the pyrazole ring of the drug molecule at the mercury electrode surface in Britton-Robinson buffer of pH 7.0. The SW adsorptive cathodic stripping voltammogram of celecoxib showed a single well-defined peak at -1.54 V (vs. Ag/AgCl/KCl(s)) using an accumulation potential of -0.70 V, frequency of 120 Hz, scan increment of 10 mV and pulse amplitude of 25 mV. Repeatability was examined for 1 x 10(-8) M CXB drug solution after 30 s pre-concentration and a mean recovery of 99.4+/-0.4% (n=5) was achieved. For 90 s preconcentration, a linear concentration range of 1 x 10(-9)-2 x 10(-8) M CXB and a detection limit of 1.86 x 10(-10) M were achieved. The proposed procedure was successfully applied for the determination of the drug in capsules and human serum with mean recoveries of 101.5+/-0.6 and 98.8+/-1.1%, respectively. A detection and quantitation limits of 1.0 x 10(-9) M (0.4 ng ml(-1)) and 4.7 x 10(-9) M (1.3 ng ml(-1)) were achieved for the determination of the drug in human serum. Moreover, the procedure was useful for study of the pharmacokinetic profile of celecoxib in a healthy volunteer after administration of a single oral dose (celebrex, 200 mg).