Effects of preparation parameters on the characteristics of chitosan–alginate nanoparticles containing curcumin diethyl disuccinate

Chitosan–alginate nanoparticles for encapsulation of curcumin diethyl disuccinate (CDD) were prepared by o/w emulsification and ionotropic gelation. The influence of parameters, including type and concentration of non-ionic surfactants, chitosan/alginate mass ratio, and concentration and rate of CDD addition into the formulation, on the characteristics of the nanoparticles were investigated. The results indicate that chitosan and alginate can be used as polymer matrices for encapsulation of CDD and that the characteristics of the nanoparticles depend on the preparative method. To obtain CDD-nanoparticles with a high encapsulation efficiency, loading capacity and yield, the nanoparticles should be prepared using 1% (w/v) Pluronic F127, a chitosan/alginate mass ratio of 0.15:1, and dropwise addition of 1 mg/ml CDD at a rate of 20 ml/h under vigorous stirring. Data from FT-IR and DSC analysis showed that there was no chemical reaction between CDD and the polymers; only physical mixing occurred and the drug was loaded in the amorphous phase inside the nanoparticle matrix. The CDD-nanoparticles prepared under optimal conditions were stable in storage at 4 °C for 3 months. In vitro cellular internalization study demonstrated CDD-nanoparticles had significantly higher cellular uptake in Caco-2 cells compared to free CDD. Thus, the chitosan–alginate nanoparticles improved cellular uptake.