2.4. Measurement of Size, Shape, and Zeta Potential

The size and surface charge (zeta potential) of the SLNs were measured using a Malvern Nano-ZS Zetasizer (Worcestershire, UK). Samples were analyzed for particle size using a disposable cuvette (DTS0012, Malvern Instruments Inc., Westborough, MA, USA). The zeta potential measurement was conducted using a folded capillary cell (DTS1070, Malvern Instruments Inc., Westborough, MA, USA). Measurements were made following dilution in Nanopure^® water, KRB, or KRB + inhibitor solutions. The solid lipid nanoparticles were negatively stained with 2% phosphotungstic acid and particle morphology was examined using a JEOL EM–1230 transmission electron microscope (JEOL, Peabody, MA, USA).