Preparation and characterization of nanostructured lipid carriers as drug delivery system: Influence of liquid lipid types on loading and cytotoxicity

•Curcumin loaded NLCs composed of different lipids were prepared and characterized.•The release kinetic of all NLC's were fitted by the Higuchi’s kinetic model.•Antioxidant activity of NLC containing black seed oil showed the highest activity.•The highest cytotoxic was obtained for curcumin-loaded NLC prepared from linseed oil.•The NLC's showed an excellent cellular uptake on MCF-7 cell line. In this study, we aimed to investigate the influence of liquid lipid types on different features of NLC. Four variations of liquid lipids such as coconut oil, fish oil, black seed oil and linseed oil were used, while for all variations, cetyl palmitate was used as the solid lipid. Different NLC were characterized and compared in terms of particle size, zeta potential, polydispersity index (PDI), drug entrapment percentage and drug loading capacity. The results indicated that NLC containing black seed oil has the smallest size. Other features like PDI, zeta potential and entrapment efficiency were the same for all the liquid lipids. By close margins, the NLC containing black seed oil had the highest percent of drug release and antioxidant activity compared to the rest. Diffusion was the major mechanism of the drug release according to the drug release kinetic fitted by Higuchi’s model. Differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FT-IR) confirmed no strong interaction between NLC constituents. The particles showed spherical shape morphology under atomic force microscopy (AFM). According to the cell viability assay on MCF-7 cell line, the curcumin loaded NLC composed of linseed oil showed better cytotoxic activity compared to the free curcumin.