Abstract: OBJECTIVE To study the pharmacokinetics and bioequivalence of two tiopromin preparations in healthy volunteers. METHODS Tiopromin concentrations of the test and the reference tablets in plasma were determined by LC-MS/MS, the pharmacokinetic parameters were calculated by DAS software, and then their bioequivalene in healthy volunteers was studied. RESULTS The main pharmacokinetic parameters of the test and reference tablets were as follows: t_1/2 were (12.8±5.3) and (10.8±4.6)min; C_max were (7.02±1.35) and (7.16±0.81)g·mL^-1; AUC_0-t were (44.0±8.3) and (45.5±6.5)g·h·mL^-1, AUC_0-∞ were (50.1±10.7) and (50.7±9.5)g·h·mL^-1, respectively. The relative bioavailability of tiopronin test and reference tablets was (96.8±11.5)%. CONCLUSION The main pharmacokinetics parameters of two preparations have no significant difference. The results demonstrated that the two preparations were bioequivalent.