Surfactant effect on the physicochemical characteristics of γ-oryanol-containing solid lipid nanoparticles

Surfactants employed in production of solid lipid nanoparticles (SLNs) play a major role on physical stability of nanoparticles, and the extent of drug dissolution and permeability into cells. In this study, cationic (cetyl pyridinium chloride), anionic (sodium dodecyl sulfate) and non-ionic (Tween 80) surfactants, as well as its combinations, were employed to formulate compritol based SLNs using γ-oryzanol as a model drug. The physicochemical properties of drug-loaded SLNs are influenced by the surfactant composition systems. Surfactant blend systems gave SLNs with superior stability compared with single surfactant systems due to enhanced incorporation of the drug within the solid lipid matrix. This may be due to synergic effects arising from electrostatic repulsion of the surfactant charges (ionic), the steric hindrance of surfactant structure (non-ionic), and ion-pairing effects between cationic and anionic ones. The cytotoxicity results demonstrated that positively charged SLNs can be uptaken into cells to a high extent. Nevertheless, the mixed surfactant systems (cationic/non-ionic and cationic/anionic/non-ionic), have remarkable advantages providing SLNs with high cell internalization capability, however, low cytotoxicity. This systematic investigation may give an insight into the practical integration of multi-surfactant systems to achieve non-toxic and highly effective drug delivery systems.