Aim: To study the pharmacokinetic (PK) properties in rabbits treated with N-Ile1-Thr2-63-desulfato-r-hirudin (rH) newly developed in China by means of bioassay in order to provide preclinical experiment basis for its development as a novel anticoagulant agent. Methods: rH plasma concentration was determined using bioassay based on ex vivo antithrombin activity of rH. Normal rabbits received iv rH 4.0, 2.0 and 1.0 mg/kg or sc rH 2.0 mg/kg, respectively. The rabbits with acute severe renal failure were given iv rH 2.0 mg/kg. Results: The bioassay described in this paper met requirements for study of PK in rabbits. The major PK parameters after iv dosing were as follows: t1/2β 58.4~59 min. Vd 0.09~0.12 L/kg, CL 0.0035~0.0040 L/(kgmin); AUC were proportional to the doses, t1/2 and CL did not change significantly with the doses. The sc bioavailability reached 94%. The rabbits suffering from acute severe renal failure presented 11-fold longer t1/2β and 13-fold greater AUC than normal healthy rabbits. Conclusion: rH exhibited rapid elimination, distribution was only limited to extracellular space and good absorption from sc site. The excretion of rH by kidneys played a very important role in the elimination of rH. The PK of rH could be described by the two- and one-compartment model after iv and sc dosing, respectively, and followed linear kinetics. Aim: To study the pharmacokinetic (PK) properties in rabbits treated with N-Ile1-Thr2-63-desulfato-r-hirudin (rH) newly developed in China by means of bioassay in order to provide preclinical experiment basis for its development as a novel rabbits with acute severe (eg, novel anticoagulant agent. Methods: rH plasma concentration was determined using bioassay based on ex vivo antithrombin activity of rH. Results: The bioassay described in this paper met requirements for study of PK in rabbits. The major PK parameters after iv dosing were as follows: t1 / 2β 58.4-59 min. Vd 0.09 ~ AUC were proportional to the doses, t1 / 2 and CL did not change significantly with the doses. The sc bioavailability reached 94%. The rabbits suffering from acute severe renal failure (0.12 L / kg, CL 0.0035-0.0040 L / (kg min) presented 11-fold longer t1 / 2β and 13-fold greater AUC than normal healt The rabbits rapid elimination, distribution was only limited to extracellular space and good absorption from sc site. The excretion of rH by kidneys played a very important role in the elimination of rH. The PK of rH could be described by the two- and one-compartment model after iv and sc dosing, respectively, and followed linear kinetics.