Hesperidin-Loaded Solid Lipid Nanoparticles: Development and Physicochemical Properties Evaluation

Although nanocarrier systems have been investigated to function as therapeutic delivery agents to specific sites of the body, the drug encapsulation method is not always well elucidated. In this work, solid lipid nanoparticles (SLN) composed by stearic acid or cetostearyl alcohol were prepared by a hot homogenization method using polyvinyl alcohol) or polysorbate as surfactant and loaded with hesperidin, a bioflavonoid that possesses many pharmacological properties. The obtained SLN were characterized by several physicochemical techniques to identify interactions between the constituents and to evaluate the drug incorporation into the nanoparticles. According to scanning electron microscopy and dynamic light scattering the hesperidin-loaded and unloaded SLN have spherical shapes, sizes ranging from 300 to 600 nm, zeta potentials varying from -35 to -20 mV, polydispersity indexes between 0.240 and 0.445, and entrapment efficiencies higher than 88%. X-ray diffraction showed the hesperidin amorphization due to its encapsulation in SLN, and also showed crystallization degree and polymorphic modification of the lipids after the SLN preparation. FTIR, Raman and Photoacoustic spectroscopy revealed no chemical reactions between drug and lipids, however, these results indicated that the drug was incorporated differently into nanoparticles based on the SLN composition. The analysis showed that stearic acid-based SLN prepared with polysorbate were more efficient to enclosure the hesperidin while the glycosydic part of the hesperidin was not entrapped in the cetostearyl alcohol-based SLN; instead, the hesperidin remained on the SLN surface due to lipid crystallization. The physicochemical characterization allowed identifying different types of hesperidin incorporation into the SLN, which can interact in a varied manner as targeted drug delivery systems.