Development of highly stable colloidal dispersions of gelled-oil nanoparticles loaded with cuminaldehyde

Abstract

The main objective of this work was to develop an aqueous dispersion of gelled-oil nanoparticles as a novel carrier for cuminaldehyde. A hot emulsification process followed by cooling to room temperature was used to prepare gelled-oil nanoparticles in the presence of monoglyceride as organogelator. The effects of monoglyceride (10% and 15% w/w of the total lipid phase) and cuminaldehyde (0, 500 and 1000 mg/L) concentrations on different characteristics (e.g. droplet size, zeta potential, physical stability, rheology, encapsulation efficiency, release behavior and morphology) of the colloidal dispersions were studied during 28-d storage. The average droplet size of freshly prepared samples was within the range of 117–138 nm with a relatively narrow distribution. Large negative ζ-potential values (−38 to −55 mV) were a proof for the kinetic stability of the colloidal dispersions. Samples which were prepared with 10% monoglyceride showed a higher physical stability over a period of 90 d. Non-Newtonian (shear-thinning) and solid-like viscoelastic properties were observed due to particle-particle interactions. The results of the temperature ramp test confirmed that the droplets were in the gelled state. An increase in the organogelator concentration decreased the interfacial tension and contact angle. Transmission electron microscopy micrographs confirmed the formation of spherical nanoparticles. The encapsulation efficiency of cuminaldehyde in gelled-oil nanoparticles was 73–87%. In-vitro release profiles exhibited that the release of cuminaldehyde from gelled-oil nanoparticles in the simulated gastric fluid was lower than its release in the simulated intestinal fluid. Moreover, the release was increased by decreasing the concentration of organogelator. The obtained colloidal dispersions have the potential to be utilized as effective encapsulation systems for poorly water-soluble nutraceuticals.