Abstract: Twelve healthy Chinese volunteers (6 men and 6 women) were administered intravenously with ceftriaxone sodium-tazobactam sodium (4∶1,1.0 g) for injection or ceftriaxone sodium (0.8 g) for injection by a cross-over study design to study the pharmacokinetics of ceftriaxone and tazobactam and to evaluate whether there were pharmacokinetic drug-drug interactions in the compound preparation.The plasma concentrations of ceftriaxone and tazobactam were measured by fully validated HPLC methods,separately.The pharmacokinetic parameters were calculated by DAS 2.0 software.The major pharmacokinetic parameters of ceftriaxone for the compound and single preparations for injection were as follows:c_max (145.3±14.0) and (123.8±17.1) μg/mL,t_max(0.52±0.04) and (0.51±0.09) h,t_1/2(9.02±1.04) and (8.93±0.72) h,MRT_0-τ(9.34±0.50) and (9.58±0.42) h,AUC_0-τ(979±90) and (984±83) μg·h/mL.Those for tazobactam in the compound preparation for injection were (10.4±1.8) μg/mL,(0.53±0.04) h,(1.20±1.66) h,(0.94±0.20) h and (8.33±2.23) mg μg·h/mL,respectively.No significant drug-drug interactions found between ceftriaxone and tazobactam by ANOVA of the pharmacokinetic parameters.