Bioequivalence of two oral formulations of nizatidine capsules in healthy male volunteers.

Purpose: The purpose of this randomized, crossover study was to compare the bioavailability of a generic and an innovator formulation of nizatidine 300 mg capsules under fasting conditions.

Methods: Twenty blood samples per period were collected from 20 healthy, Arab male volunteers over 16 h, plasma nizatidine concentrations were determined by HPLC assay, and pharmacokinetic parameters were determined by the non-compartmental method.

Results: Mean+/-SD C(max), T(max), AUC(0-->t), AUC(0-->infinity), and t1/2 were 2.96+/-0.54 and 3.28+/-0.68 microg/ml, 1.31+/-0.70 and 0.93+/-0.38 h, 9.04+/-1.66 and 9.03+/-1.94 microg x h/ml, 9.17+/-1.64 and 9.12+/-1.94 microg x h/ml, and 1.64+/-0.21 and 1.58+/-0.22 h for the generic and innovator formulation, respectively. The parametric 90% confidence intervals on the mean of the difference between log-transformed values were 98.06% to 103.21%, 98.74% to 103.71%, and 83.37% to 101.34%, for AUC(0-->t), AUC(0-->infinity), and C(max), respectively.

Conclusion: The results indicate that these two formulations are equivalent in the rate and extent of absorption.