Stability and in vivo evaluation of pullulan acetate as a drug nanocarrier

To develop pullulan acetate nanoparticles (PANs) as a drug nanocarrier, pullulan acetate (PA) was synthesized and characterized. Its acetylation degree determined by the proton nuclear magnetic resonance ((1)H NMR) was 2.6. PANs were prepared by the solvent diffusion method and characterized by transmission electron microscope (TEM), size distribution, and zeta potential techniques. PANs had nearly spherical shape with a size range of 200-450 nm and low zeta potentials both in distilled water and in 10% FBS. The storage stability of PANs was observed in distilled water. PANs were stored for at least 2 months with no significant size and zeta potential changes. The safety of PANs was studied through single dose toxicity test in mice, and the result showed that PANs were well tolerated at the dose of 200 mg/kg in mice. Epirubicin-loaded PANs (PA/EPI) were also prepared and characterized in this study. Moreover, the in vivo pharmacokinetics of PA/EPI was investigated. Compared with the free EPI group, the PA/EPI group exhibited higher plasma drug concentration, longer half-life time (t(1/2)) and the larger area under the curve (AUC). All results suggested that PANs were stable, safe, and showed a promising potential on improving the bioavailability of the loaded drug of the encapsulated drug.