Changes in pharmacokinetics of single dose of fentanyl in simulated high altitude in rats

Objective To explore the pharmacokinetic changes of single dose of fentanyl in rats in a simulated high-altitude and contributing factors. Methods Thirty-six healthy female SD rats (6~8 weeks old, 250±20 g) were randomly divided into high-altitude-acute-exposure group (group A), high-altitude-chronic-exposure group (group S) and control group (group C) through random number table, with 12 rats in each group.The group A and S were housed in a low-pressure chamber simulating the high altitude of 5 000 m above sea level for 3 and 30 d respectively, and the group C was housed out of the chamber (at an altitude of 300 m).A single dose of fentanyl was administered through the femoral vein to 6 rats randomly selected from each group.Liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to detect blood concentrations of fentanyl and WinNonlin 8.2 software was used to calculate the pharmacokinetic parameters, while blood samples were taken through the femoral artery before and in 1, 2, 4, 8, 15, 30, 60, 1