# Freeze-Dried Pickering Emulsions with Curcumin: The Role of Stabilizers and Cryoprotectants

## TL;DR

This study explores freeze-dried emulsions with curcumin, showing how stabilizers and cryoprotectants affect their properties and potential for skin healing.

## Contribution

The novel contribution is the investigation of CNC/CAS addition order and cryoprotectant effects on curcumin emulsions and their transdermal properties.

## Key findings

- Curcumin emulsions with CNC and CAS showed controlled release and antioxidant activity.
- Emulsions stabilized with CNC first and d-glucose had best-preserved droplets after freeze-drying.
- Curcumin mainly remained on skin surface with limited deeper penetration but showed healing potential.

## Abstract

This study investigated
freeze-dried Pickering emulsions stabilized
by a combination of cellulose nanocrystals (CNCs) and sodium caseinate
(CAS), with encapsulated curcumin. Our approach focused on the order
of CNC/CAS addition and its influence on emulsion properties, along
with the effect of three different cryoprotectants (sucrose, d-mannitol, and d-glucose) on the preservation of emulsion
droplets. In the study, controlled release of curcumin from freeze-dried
emulsions was achieved, attributed to the composition of the stabilizing
layer and the cryoprotectant used. The emulsions were partially able
to withstand freeze-drying and could be redispersed to samples with
droplets bigger than those observed before freeze-drying. The best-preserved
droplets came from emulsions stabilized first by CNC particles and
then by CAS addition and protected with d-glucose. Transdermal
penetration studies revealed that curcumin was mainly present on the
skin’s surface and at the stratum corneum,
with limited penetration into deeper skin layers. Nevertheless, the
samples showed outstanding antioxidant activity and no cytotoxicity
effects, demonstrating their promising potential to positively influence
the healing of the skin.