Pharmacokinetic Profiles of Two Branded Formulations of Piroxicam 20mg in Healthy Korean Volunteers by a Rapid Isocratic HPLC Method

The aim of this study was to develop and validate for determination of piroxicam in human plasma by new rapid HPLC method and to compare the relative bioavailability of two branded formulations of piroxicam in healthy Korean volunteers. The analysis running time of piroxicam was just 2 minutes using C 18 column (100 x 4.6 mm, 5 μm) with variable wavelength detector (at 355 nm). This HPLC method was validated by examining the precision and accuracy for interand intra-day analysis. A randomized, open-label, single dose, 2-period crossover method was performed in 28 subjects. For analysis of pharmacokinetic properties, the blood samples were drawn at 0, 1, 2, 3, 4, 5, 6, 12, 24, 48, 96 and 168 hours after dosing. The standard curve was linear (R = 0.9999) over the concentration range of 0.1 6 μg/mL. The relative standard deviation (R.S.D.) and accuracy were 0.2 6.1 % and 95.4 104.0 %. After single dose of piroxicam 20 mg, the plasma pharmacokinetic parameters, C max , T max , t 1/2 and AUC t were 2.15 ± 0.25 μg/mL, 2.44 ± 1.15 h, 46.84 ± 8.73 h and 107.42 ± 27.25 μg·h/mL in the test drug. No significant differences were found based on analysis of variance, with mean values and 90% CIs of test/reference ratio for these parameters as follows: C max was 0.9351-1.0377; AUC 0-168 was 0.9510-1.0752. The developed method was successfully applied to bioequivalence study of two branded piroxicam capsules in 28 healthy Korean. The results of pharmacokinetics showed two branded piroxicam 20 mg formulations were bioequivalent, based on the regulatory definition.