In this study, a functional nanostructured lipid carriers (NLCs)-based hydrogel was developed to repair the damaged epidermal skin barrier. NLCs were prepared via a high-energy approach, using argan oil and beeswax as liquid and solid lipids, respectively, and were loaded with ceramides and cholesterol at a physiologically relevant ratio, acting as structural and functional compounds. Employing a series of surfactants and optimizing the preparation conditions, NLCs of 215.5 ± 0.9 nm in size and a negative zeta potential of −42.7 ± 0.9 were obtained, showing acceptable physical and microbial stability. Solid state characterization by differential scanning calorimetry and X-ray powder diffraction revealed the formation of imperfect crystal NLC-type. The optimized NLC dispersion was loaded into the gel based on sodium hyaluronate and xanthan gum. The gels obtained presented a shear thinning and thixotropic behavior, which is suitable for dermal application. Incorporating NLCs enhanced the rheological, viscoelastic, and textural properties of the gel formed while retaining the suitable spreadability required for comfortable application and patient compliance. The NLC-loaded gel presented a noticeable occlusion effect in vitro. It provided 2.8-fold higher skin hydration levels on the ex vivo porcine ear model than the NLC-free gel, showing a potential to repair the damaged epidermal barrier and nourish the skin actively.
Laurus nobilis hydrosol (HyLN), a water-soluble byproduct of essential oil extraction, containing beneficial antioxidants and antimicrobial compounds, was used as a sustainable ingredient in the development of a natural antioxidant-rich hydrogel formulation. Hydrogels were formulated using sodium hyaluronate and xanthan gum, natural ingredients with beneficial effects on the skin, while β-cyclodextrin (βCD) was added to enhance the stability of antioxidants in HyLN. Extensive rheological and textural analyses were employed to optimize the hydrogel formulation for dermal administration, while stability studies assessed the chemical and physical stability of developed formulations. A combination of sodium hyaluronate and xanthan gum provided several HyLN hydrogel formulations with tunable rheological and textural properties, presenting adequate physical and microbiological stability over 6 months of storage. The use of βCD failed to stabilize inherently unstable antioxidants in HyLN hydrogels, yet their residual antioxidant activity remained notable. An in vitro scratch test using a human keratinocyte cell line showed that the developed HyLN gel does not interfere with wound healing. HyLN hydrogels showed a pronounced occlusive effect in vitro, reaching up to 80% of that measured for Vaseline, which helps maintain skin hydration and appearance.