Abstract: Aim The relative bioavailability of domestic ibudilast sustained release capsules in healthy volunteers was observed.Methods A single oral dose of 20 mg of imported and domestic ibudilast sustained release capsules and 10 mg of ibudilast raw material was separately given to 12 healthy volunteers in a randomized crossover study.Ibudilast concentration in plasma was determined by HPLC method.Results The C_max were (54.9±9.7), (60.7±9.1)and (62.2±11.5)μg·L^-1;the t_max were (3.8±0.8), (3.9±0.8)and (1.8±0.3)h; the t_1/2(ke) were (1.5±1.4), (12.1±1.0) and (3.5±0.5)h, and the A UC_(0~t) were (618.1±57.7), (588.1±66.6)and (233.0±46.4)μg·h ·L^-1 in imported capsule group, domestic capsule group and raw material group respectively.The relative bioavailability of domestic sustained release capsules of ibudilast is (95.6±11.0)%.Conclusion The results of statistical analysis demonstrate that the imported and domestic sustained capsules have significant character of significantly sustained release and are bioequivalent.

Key words: ibudilast, relative bioav ailabity, pharmacokinetics