# Polymeric Nanocapsules Containing Kojic Acid Dipalmitate and Rosehip Oil: Development and Evaluation of Preliminary Efficacy and Safety for Skin Whitening

## TL;DR

This paper describes the development of nanocapsules containing kojic acid dipalmitate and rosehip oil for safe and effective skin whitening.

## Contribution

The study introduces a novel nanocapsule formulation with high encapsulation efficiency and improved tyrosinase inhibition for skin whitening.

## Key findings

- PLGA nanocapsules showed no KDP degradation after 180 days of refrigerated storage.
- KDP in nanocapsules inhibited tyrosinase by 17% in vitro and reduced melanin by 25%.
- The formulation demonstrated higher antioxidant activity than free kojic acid.

## Abstract

Polymeric nanocapsules associated with kojic acid dipalmitate
(KDP)
and rosehip oil can be a strategy to obtain high-performance skin
whitening/lightning formulations. Nanocapsules containing 0.1% of
KDP and 5% of rosehip oil were developed with different polymers (Eudragit
RS100, Eudragit S100, poly­(ε-caprolactone) (PCL) and poly­(d,l-lactide-co-glycolide) (PLGA))
to limit the contact of KDP with the external media and avoid its
degradation. The nanocapsules had a diameter of less than 200 nm,
with suitable size distribution, a pH range between 2.5 and 5.0, a
KDP content of 0.9 mg/mL and an encapsulation efficiency above 99%.
The zeta potential was positive for the Eudragit RS100 nanocapsules
and negative for the other nanocapsules. The PLGA nanocapsules were
selected due to better stability results, since there was no decay
in KDP content after 180 days (refrigerated storage). The in vitro
skin permeation assay showed that KDP reaches the epidermis. This
formulation showed in vitro antioxidant activity through both the
DPPH assay and the β-carotene/linoleic acid assay when used
at 25 μg/mL of KDP, with higher activity than a kojic acid solution
(KDP correspondent concentration) and, at 13.75 μg/mL, inhibited
tyrosinase in vitro to 17%, significantly greater than the kojic acid
solution. A 25% melanin reduction was obtained after normal human
epidermal melanocytes (NHEM) were treated with 3.1 μg/mL of
KDP. Cytocompatibility was observed after 24 h treatment with up to
6.25 μg/mL of the formulation in fibroblast-like cells (3T3-L1)
and up to 3.1 μg/mL in NHEM. Therefore, PLGA nanocapsules containing
KDP and rosehip oil have potential for use in skin whitening/lightning
formulations.