Chitosan/Virgin Coconut Oil-Based Emulsions Doped with Photosensitive Curcumin Loaded Capsules: A Functional Carrier to Topical Treatment

In recent years, there has been a growing interest in developing smart drug delivery systems
based on natural resources combined with stimulus-sensitive elements. This trend aims to formulate
innovative and sustainable delivery platforms tailored for topical applications. This work proposed
the use of layer-by-layer (LbL) methodology to fabricate biocompatible photo-responsive multilayer
systems. These systems are composed of a polyoxometalate inorganic salt (POM) ([NaP5W30O110]14−)
and a natural origin polymer, chitosan (CHT). Curcumin (CUR), a natural bioactive compound, was
incorporated to enhance the functionality of these systems during the formation of hollow capsules.
The capsules produced, with sizes between 2–5μm (SEM), were further dispersed into CHT/VCO
(virgin coconut oil) emulsion solutions that were casted into molds and dried at 37 ◦C for 48 h.
The system presented a higher water uptake in PBS than in acidic conditions, still significantly
lower than that earlier reported to other CHT/VCO-based systems. The drug release profile is
not significantly influenced by the medium pH reaching a maximum of 37% ± 1% after 48 h. The
antioxidant performance of the designed structures was further studied, suggesting a synergistic
beneficial effect resulting from CUR, POM, and VCO individual bioactivities. The increased amount
of those excipients released to the media over time promoted an increase in the antioxidant activity
of the system, reaching a maximum of 38.1% ± 0.1% after 48 h. This work represents a promising
step towards developing advanced, sustainable drug delivery systems for topical applications.