A Novel Strategy for Topical Administration by Combining Chitosan Hydrogel Beads with Nanostructured Lipid Carriers: Preparation, Characterization, and Evaluation

The objective of the present study was to develop and evaluate NLC–chitosan hydrogel beads for topical administration. The feasibility of the preparation technology was verified by investigating various formulation factors and the impact of chitosan hydrogel beads on the NLC. The encapsulation efficiency of NLC–chitosan hydrogel beads was above 95% in optimized process conditions. The physical characterization of the NLC–chitosan hydrogel beads showed that the NLC was distributed within the network of the chitosan hydrogel beads. Furthermore, the incorporation of NLC into the chitosan hydrogel beads was related to the electrostatic interaction between the surface of the NLC and chitosan, which influenced the lipid ordering degree of the NLC and contributed to the stability. The stability studies showed that the retention rate of quercetin in the NLC–chitosan hydrogel beads was 88.63 ± 2.57% after 10 months of storage under natural daylight. An in vitro permeation study showed that NLC–chitosan hydrogel beads exhibited superior ability in enhancing skin permeation by hydrophobic active ingredients compared to the NLC and significantly increased skin accumulation. These studies demonstrated that the use of NLC–chitosan hydrogel beads might be a promising strategy for the delivery of hydrophobic active ingredients in topical administration.