Nanostructured lipid carriers incorporating prickly pear seed oil for the encapsulation of vitamin A.

BACKGROUND: Solid lipid nanoparticles (SLNs) are dispersions synthesized by replacing liquid lipid in an o/w emulsion with solid lipids. Nanostructured lipid carriers (NLCs) improve on some of the major limitations of the SLNs as NLCs use liquid lipids along with crystalline solid fatty acids to build the core.

AIMS: This work aims to investigate the potential advantage of using Prickly Pear (PP) seed oil to develop NLCs for topical delivery of vitamin A.

METHODS: Four PP-based NLC formulations with varying composition have been developed using the hot homogenization method and compared with a SLN formulation that is free of PP oil. The effect of this variation on entrapment efficiency, in vitro release behavior, and ex vivo permeation, was investigated. Additionally, particle size and polydispersity index (PDI) upon storage, zeta potential, and thermal behavior were characterized.

RESULTS: PP-based NLCs exhibited smaller particle size in the range of 215-244 nm, and PDI <0.3. In contrast, SLN having no PP oil had a larger diameter of 365 nm, with heterogeneous distribution (0.92 PDI). In assessing the in vitro release, an inverse relationship was observed between the diffusion flux and the entrapment efficiency. The changes in the constituting matrix of the NLCs lead to a significant potential variation in their properties, and hence allowing it to be tailored for specific usages.

CONCLUSIONS: In all cases, NLCs formulations have shown superior attributes to the SLN carriers. This was linked in most cases to the presence of PP oil, supporting the value of utilizing PP oil in cosmeceutical applications.