Comparative pharmacokinetic study of two kinds of altrenogest oral solutions for sows

This study was to compare the pharmacokinetic characteristics of domestic altrenogest oral solution (DAOS) or imported altrenogest oral solution (IAOS) in healthy sows. A single administration (1 mg/kg body weight) of DAOS or IAOS was performed in sixteen healthy sows according to a two-period crossover design. Plasma concentrations of altrenogest (AT) were measured by high performance liquid chromatography coupled to a tandem mass spectrometer (HPLC-MS/MS) and the concentration-time data of AT was analyzed by WINNONLIN 5.2. It was suggested that the main pharmacokinetic parameters of DAOS and IAOS were as follows: C was 227.59 ± 83.35 ng/mL and 152.83 ± 80.34 ng/mL, T was 1.16 ± 0.52 h and 1.58 ± 0.85 h, t_1/2 was 3.63 ± 0.72 h and 3.45 ± 0.63 h, MRT was 5.02 ± 0.79 h and 5.21 ± 0.87 h, AUC_0- was 1050.23 ± 409.80 h·ng/mL and 778.22 ± 397.84 h·ng/mL, and AUC_0-∞ was 1060 h·ng/mL and 786 h·ng/mL, respectively. The relative bioavailability of DAOS was 134.9%. Above results indicated that oral DAOS was better absorbed than IAOS, C of DAOS was higher than that of IAOS (p < 0.05). However, there was no significant difference in the main pharmacokinetic parameters between oral DAOS and IAOS (p > 0.05). Our data confirmed that the absorption, fast elimination and bioavailability of DAOS in sows were better than those of IAOS.