Abstract: 16 healthy cats were randomly divided into two equal groups, a single dose of parallel test design was used. The pharmacokinetics of test substance and reference substance milbemycin oxime-praziquantel tablets were studied in cats by oral route (4 mg/kg·bw). The plasma concentrations of milbemycin oxime and praziquantel were determined by high-performance liquid chromatographic method, and pharmacokinetic parameters were calculated by kinetica program. The main parameters of reference substance were as follows, T_1/2β, T_max, C_max, AUC and MRT of milbemycin oxime were (20.08±7.57)h, 6.00 h, (764.43±251.40)ng/mL, (15.00±5.05)ng/(L·h) and (18.60±1.52)h, respectively; and T_1/2β, T_max, C_max, AUC and MRT of praziquantel were (6.27±5.26)h, (3.88±0.35)h, (1018.25±200.19)ng/mL, (8.69±2.07)ng/(L·h) and MRT (6.56±1.07)h, respectively. The main parameters of test substance were as follows, T_1/2β, T_max, C_max, AUC and MRT of milbemycin oxime were (15.07±4.05)h, (5.25±1.04)h, (806.65±299.01)ng/mL, (15.18±5.97)ng/(L·h) and (17.47±1.97)h, respectively, and the relative bioavailability was 101.20%; T_1/2β, T_max, C_max, AUC and MRT of praziquantel were (11.11±4.62)h, (5.25±1.04)h, (880.47±241.27)ng/mL, (9.64±2.76)ng/(L·h) and (10.52±1.52)h, respectively, and the relative bioavailability was 119.16%. Compared with reference substance, significant difference in T_1/2β was observed in milbemycin oxime (P<0.05), and significant difference in T_max was also observed in praziquantel (P<0.05), other parameters were no significant differences (P>0.05).The results showed that the test substance of milbemycin oxime-praziquantel tablets compared with the reference substance had similar pharmacokinetic characteristics in cats by oral route.

Key words: milbemycin oxime-praziquantel tablets; cats; oral administration; pharmacokinetic