Pharmacokinetics and bioequivalence testing of generic fluconazole preparations in healthy Thai volunteers

AIM: To determine the bioequivalence of two oral formulations of generic fluconazole in twelve healthy Thai volunteers. SUBJECTS, MATERIALS AND METHODS: The test preparation was Flucozole (Siam Bheasach, Thailand) and the reference was Diflucan (Pfizer Inc.). The two products were administered as 200 mg single oral doses in a two-period crossover design with a two-week washout period. After drug administration, serial blood samples were collected over a period of 72 hours. Serum fluconazole concentrations were determined by HPLC, and the pharmacokinetic parameters were analyzed by non-compartmental analysis. RESULTS: The time to reach the maximal concentration (Tmax, hour) of Flucozole (1.18 +/- 0.56) was statistically faster than that of Diflulan (1.59 +/- 0.54). The 90% confidence intervals of the AUC(0 - infinity) ratio and the Cmax, ratio muT/muR for Flucozole/Diflucan were 0.97 - 1.20 and 1.01 - 1.26, respectively. These values were within the acceptable bioequivalence intervals of 0.80 - 1.25 and 0.7 - 1.43 for the ratio of the average AUC(0 - infinity) and Cmax, respectively. CONCLUSION: Thus, our study demonstrated the bioequivalence of Flucozole and Diflucan with respect to the rate (Cmax) and extent of absorption (AUC(0 - infinity).