Green solid lipid nanoparticles by coacervation of fatty acids: An innovative cosmetic ingredient for the delivery of anti-age compounds through the skin.

Summary

Using a solvent-free, low-energy fatty-acid coacervation route, the authors created “green” SLNs from natural soaps, loaded them with a UV filter and two anti-age actives, and demonstrated physicochemical stability (up to 1 year in finished serum/hydrogel). Ex vivo Franz cell studies showed enhanced skin permeation, and human testing indicated safety plus improvements in hydration and elasticity.

Key Findings

• Solvent-free fatty-acid coacervation yielded “green” SLNs from natural soaps (Mango and Shea) loaded with a UV filter and anti-age actives.
• Finished serum/hydrogel showed physicochemical and organoleptic stability up to 1 year (best performance with Mango SLN–based serum).
• Franz cell (pig-ear skin) experiments demonstrated enhanced permeation of actives when encapsulated in SLNs.
• Human testing (patch/challenge) indicated safety; an efficacy study in volunteers showed improvements in skin hydration and elasticity.

Clinical Implications

Cosmetic formulators and clinicians can leverage solvent-free SLNs to improve delivery of actives while meeting sustainability goals; early human data suggest benefits for hydration and elasticity that justify controlled clinical trials.

Limitations

• Human efficacy study lacks randomization/control and does not report sample size in the abstract
• Ex vivo pig skin models may not fully replicate human skin barrier variability

Future Directions

Conduct randomized controlled trials with larger cohorts, expand to diverse actives and skin types, and assess long-term real-world effectiveness and environmental footprint.