Objective: To calculate pharmacokinetic parameters of brucine and strychnine in rats after oral administration of Rebiqing tablets and Strychni Semen Pulveratum

and compare their pharmacokinetic characteristics in plasma. Method: UPLC-MS/MS was employed to determine contents of brucine and strychnine in rat plasma with Agela Venusil ASB C18column (2.1 mm×50 mm

3 μm)

taking acetonitrile-0.15% formic acid (60: 40) as mobile phase at 0.1 mL·min-1.Column temperature was 35 ℃.Internal standard was clenbuterol hydrochloride

UPLC-MS/MS was performed with electrospray ionization (ESI) and operated in positive mode in multiple reaction monitoring (MRM).Reaction selected ions were m/z 395.22-243.97 for brucine

m/z 335.14-183.96 for strychnine and m/z 277.11-202.87 for internal standard.Samples were extracted from rat plasma by liquid-liquid extraction.Pharmacokinetic parameters were calculated by DAS 2.1 software. Result: Main pharmacokinetic parameters of brucine in Rebiqing tablets and Strychni Semen Pulveratum were as follows:tmax of (27±11)

(40±12) min

Cmax of (5.6±1.2)

(4.5±1.7) μg·L-1

AUC0-t of (922±96)

(710±126) μg·min·L-1

CL/F of (4 596±306)

(87±34) L·min-1·kg-1;parameters of strychnine in them were (30±9)

(42±14) min

(27.3±10.8)

(15.9±7.0) μg·L-1

(3 957±651)

(2 031±256) μg·min·L-1 and (880 ±84)

(49±10) L·min-1·kg-1

respectively. Conclusion: Pharmacokinetic behavior of brucine and strychnine are well fitted to two-compartment model in rats.Compared with Strychni Semen Pulveratum

Rebiqing tablets can significantly improve oral bioavailability

accelerate absorption and elimination rate of brucine and strychnine.