PEGylated niosomes-mediated drug delivery systems for Paeonol: preparation, pharmacokinetics studies and synergistic anti-tumor effects with 5-FU.

This work describes the preparation of a PEGylated niosomes-mediated drug delivery systems for Paeonol, thereby improving the bioavailability and chemical stability of Paeonol, prolonging its cellular uptake and enhancing its synergistic anti-cancer effects with 5-Fu. PEGylated niosomes, which are prepared from biocompatible nonionic surfactant of Spans 60 and cholesterol, and modified with PEG-SA. Pae-PEG-NISVs were evaluated in vitro and in vivo. The cytotoxicity of Pae-PEG-NISVs was investigated against HepG2 cells. Fluorescence microscope was used to detect the apoptotic morphological changes. Growth inhibition assays were carried out to investigate whether Pae-PEG-NISVs could enhance the antiproliferative effects of Pae co-treated with 5-FU on HepG2 cells. The optimized Pae-PEG-NISVs had mean diameters of approximately 166 nm and entrapment efficiency (EE) of 61.8%. Furthermore, the in vitro release study of Paeonol from PEGylated niosomes exhibited a relatively prolonged release profile for 12 h. Pharmacokinetic studies in rats after i.v. injection showed that Pae-PEG-NISVs had increased elimination half-lives (t1/2, 87.5 versus 17.0 min) and increased area under the concentration-time curve (AUC0-t, 38.0 versus 19.48 µg/ml*min) compared to Paeonol solution. Formulated Paeonol had superior cytotoxicity versus the free drug with IC50 values of 22.47 and 85.16 µg/mL at 24 h on HepG2 cells, respectively, and we found that low concentration of Pae-PEG-NISVs and 5-Fu in conjunction had obviously synergistic effect. Our results indicate that the PEG-NISVs system has the potential to serve as an efficient carrier for Paeonol by effectively solubilizing, stabilizing and delivering the drug to the cancer cells.