Abstract: Objective To study the pharmacokinetics of prostaglandin(PGE₁) freeze-dried lipid microspheres in beagle dogs and provide reference for its clinical usage. Methods Twenty-four beagle dogs were divided randomly into the control group, low-dose group, medium-dose group and high-dose group, six in each group. Dogs were injected intravenously with reference preparation "Kaishi" and PGE₁ freeze-dried lipid microspheres with 20, 32 and 64μg/dog, respectively. The blood samples were collected at different time points. LC-MS/MS method was used to detect the plasma concentration of PGE₁ in beagle dogs. Results After intravenous injection at a dose of 32μg/dog, t_1/2 of PGE₁ in plasma was (7.5±3.7) min, t_max was (7.6±2.9) min, C_max was (105.0±40.4)ng/L, and AUC_{(0-18 min)} was (933.1±359.0) ng·min/L, which had no difference from those of the reference formulation (P>0.05). AUC_{(0~18 min)} and C_max were positively correlated with different dose levels. Besides, the pharmacokinetic result showed there were no significant statistical difference between the sexes (P>0.05). Conclusion PGE₁ freeze-dried lipid microspheres have similar pharmacokinetic characteristics in comparison with the reference formulation, and different doses do not affect PGE₁ pharmacokinetic profile in beagle dogs.

Key words: Prostaglandin E₁, Lipid microspheres, Pharmacokinetics, LC-MS/MS