Objective To prepare trifolin-phospholipids complex/chitosan nanoparticles (Tri-PC/CS-NPs), and investigate its in vivo pharmacokinetic behavior and protective effect on acute liver injury. Methods Trifolin-phospholipids complex (Tri-PC) was prepared by solvent evaporation method. Single factor experiments combined Box-Behnken design-response surface methodology (BBD-RSM) were used to optimize the prescriptions of Tri-PC/CS-NPs. Transmission electron microscope (TEM) was employed to observe microscopic appearance of Tri-PC/CS-NPs, X-ray powder diffraction (XRPD) was used to analyze crystal form of Tri-PC/CS-NPs. Saturated solubility, oil/water partition coefficient and drug release behavior in simulated gastrointestinal fluids of trifolin, Tri-PC and Tri-PC/CS-NPs were compared. SD rats were administered intragastrically with trifolin, Tri-PC and Tri-PC/CS-NPs, respectively. Blood drug concentration was determined, and the main pharmacokinetic parameters were calculated. The model of acute liver injury was established, and the protective effect of trifolin, Tri-PC, Tri-PC/CS-NPs on acute liver injury were compared. Results Optimal formulations of Tri-PC/CS-NPs: the volume of water phase was 20.50 mL, the mass ratio of Tri-PC to chitosan was 4.15:1, and the mass fraction of Poloxamer 188 was 0.10%. Envelopment efficiency, drug loading, particle size and ζ potential were (84.80 ± 1.21)%, (15.56 ± 0.10)%, (197.74 ± 5.58) nm and (32.69 ± 1.14) mV, respectively. The appearance of Tri-PC/CS-NPs were spherical. The state of trifolin changed into amorphous form in Tri-PC and Tri-PC/CS-NPs. Tri-PC and Tri-PC/CS-NPs significantly enhanced the saturated solubility and oil/water partition coefficient of trifolin (P < 0.01). Cumulative release rate of Tri-PC and Tri-PC/CS-NPs were 56.68% and 88.45% in 18 h, respectively. The drug release process of Tri-PC/CS-NPs conformed to the Weibull model. Compared with trifolin, the relative bioavailability of Tri-PC and Tri-PC/CS-NPs was enhanced to 2.41-fold and 5.36-fold, respectively. Tri-PC and Tri-PC/CS-NPs effectively enhanced the protective effect of trifolin against acute liver injury, and the protective effect of Tri-PC/CS-NPs was superior to that of Tri-PC. Conclusion Tri-PC/CS-NPs changed the pharmacokinetic behavior of trifolin in vivo, effectively promoted the absorption of trifolin, and enhanced the protective effect of trifolin on acute liver injury.

trifolin  /  phospholipids complex  /  chitosan  /  nanoparticles  /  Box-Behnken design-response surface methodology  /  solubility  /  oil/water partition coefficient  /  bioavailability  /  acute liver injury