Paeonol nanoemulsion for enhanced oral bioavailability: optimization and mechanism

The aim of this work was to optimize a nanoemulsion formulation and explain its absorption mechanism in improving the oral bioavailability of paeonol. Method: The bioavailability of paeonol was compared between paeonol nanoemulsion group and paeonol suspension group. The in situ single-pass intestine perfusion method, in vitro everted gut sacs method, Western blot analysis and Caco-2 cell transport studies were used to investigate the absorption mechanism of nanoemulsion. Results: Nanoemulsion was proved to enhance the bioavailability of paeonol. P-glycoprotein (P-gp) mediated efflux might be the main reason affecting the oral absorption of paeonol. The prepared nanoemulsion prevented the P-gp-mediated efflux and enhanced the bioavailability of paeonol. Conclusion: The overall results revealed that nanoemulsion was an effective vehicle to improve the oral bioavailability of paeonol which resulted from the prevention of P-gp efflux probably.