Characterization and evaluation of metformin-loaded solid lipid nanoparticles for celluar and mitochondrial uptake

Considered a popular drug for diabetes in recent years, metformin was determined to have a moderate anti-tumor effect, particularly in breast cancer. In this study, the anticancer mechanism of metformin was verified by preparing solid lipid nanoparticles (SLNs) and chitosan-modified solid lipid nanoparticles (CSLNs) containing metformin and then estimating the potential of these SLNs for uptake in cells and mitochondria. Metformin-SLNs were prepared using an emulsification and low-temperature solidification method. The mean particle size, zeta potential, entrapment efficiency, and loading efficiency of metformin-SLNs and metformin chitosan-modified SLNs were 102.3 +/- 4.16 and 200.1 +/- 17.69 nm, -21.25 +/- 4.89 and 50.6 +/- 4.09 mv, 26.25 +/- 2.59% and 33.6 +/- 2.21%, and 1.74 +/- 0.16% and 1.46 +/- 0.10%, respectively. TEM images showed that both the nanoparticles had spherical morphologies with no aggregation. Results of cellular and mitochondrial uptake showed that the metformin-SLNs were easier to uptake in cells and mitochondria than the pure drug group (that was the control group without SLN structure modification). The findings of this research provide a basis for conducting further studies on the anticancer mechanism of metformin.