Relative bioavailability of ethambutol hydrochloride tablets in human subjects

Objective To study the pharmacokinetics and bioavailability of test andreference of ethambutol in human subjects. Methods A single oral adminstration of1 000 mg test and reference tablets were given to 20 healthy male volunteersaccording to a randomized crossover design. The concentrations of ethambutol inplasma were determined by a LC/MS (high-pressure liquid chromatographic-mass)method. The pharmacokinetic parameters and bioavailability of test tablets werecompared with those of reference tablets. Results After a single oral adminstrationof 1 000 mg test and reference tablets, the pharmacokinetic parameters were asfollows: Cmax were (4.0±1.4) and (4.0±1.2) mg.L-1; tmax were (2.8±1.2) and (2.6±0.9) h; t1/2 were (10.4±1.3) and (10.8±1.3) h; AUC0-36 were (22.4±4.4) and(21.9±3.5) mg.h.L-1; AUC0-∞ were (23.7±4.5) and (23.3±3.8) mg.h.L-1 for testand reference tablets, respectively. The relative bioavailability of test tablets was(102.2±11.7) %. Conclusion The two preparations were bioequivalent.