Encapsulation and Release of Citral Using Nanostructured Lipid Carriers: A Study on the Impact of Different Preparation Methods

Abstract

The study compared the effects of three different preparation methods (dispersion, ultrasonication and microfluidization) on the encapsulation of citral in nanostructured lipid carrier (NLC). We studied the effects of surfactant, citral addition amount and solid-to-liquid lipid mass ratio over the NLC characteristics. The obtained citral loaded NLC had a particle size of 192.8 ± 3.61 nm, a PDI of 0.243 ± 0.01, a Zeta potential of -34.2 ± 0.34 mV, an entrapment efficiency (EE%) of 78.37 ± 3.76%, and a loading efficiency (LE%) of 26.19 ± 1.26%. All NLC showed an improvement in the physicochemical stability of citral through encapsulation. In addition, the release kinetics revealed that the release of citral after 35 days storage was significantly lower from ultrasonication-NLC (almost no release at 4°C, 61.09% at 25°C) than that from microfluidization-NLC (9.63% at 4°C, 72.56% at 25°C). It is possible that the energy input of ultrasonication makes the interaction force within particles stronger. While microfluidization-NLC has a defective lipid structure leading to easier release of citral. Therefore, ultrasonication is more suitable for the preparation of citral loaded NLC. This research provides an essential reference for the process of preparing citral loaded NLC.

Keywords: dispersion, ultrasonication, microfluidization, encapsulation, polycrystalline transformation, release kinetic.