Preparation of paeonol nanoemulsion and investigation of vascular endothelial cells uptake

In order to improve the poor solubility and low bioavailability of paeonol (Pae), paeonol-nanoemulsion (Pae-NE) was prepared, and its effect on uptake of human umbilical vein endothelial cells (HUVECs) was investigated.Pae-NE was prepared by phase inversion composition (PIC), the formulation of Pae-NE was optimized by single factor method and central composite design-response surface method (CCD), and the pharmaceutical properties were further characterized.Moreover, MTT was applied to evaluate the toxicity of Pae-NE on HUVECs, and the cellular uptake efficiency of Pae-NE was detected by fluorescence microscopy and flow cytometry.The results showed that the optimal formulation of Pae-NE was 20 mg of Pae, 55.1 mg of LCT, 144.9 mg of MCT, 600 mg of HS15, and 200 mg of 1,2 propylene glycol.The Pae-NE appearance was a light blue emulsion, and the average particle size is (25.69 ± 0.03) nm, with PDI of 0.182 ± 0.09, Zeta potential of -(4.01 ± 0.30) mV and good stability.The drug loading of Pae-NE was (1.967 ± 0.28) mg/mL and encapsulation rate of (99.36 ± 0.1)%.Pae-NE performed no significant effect on HUVECs growth in the Pae concentration range of 10^-1-10^-3 μg/mL.Moreover, NE as a drug delivery carrier significantly enhanced the uptake efficiency of Pae on HUVECs.In conclusion, Pae-NE preparation method was simple and stable, and promotes HUVECs uptake efficiency of Pae, suggesting that NE was a better dosage form reference for the lipid-soluble drug of Pae.