Transdermal peptide delivery using solvent-free thermosponge nanoparticles to improve the anti-aging efficacy of peptides in clinical trials

With the worldwide increase in life expectancy, the human desire to maintain youth and beauty has intensified, leading to rapid advances in the cosmetic industry. However, recently proposed peptide-based formulations with anti-aging properties exhibit low skin-penetration ability. To overcome this limitation, an anti-wrinkle peptide (Regentide®-AWP013; RG) with time- and dose-dependent cell proliferation, wound-healing activity, and no cytotoxicity was developed in this study. The stability and efficacy of RG were improved using solvent-free thermosponge nanoparticles (TNPs) comprising FDA-approved biocompatible materials, which were developed using a simple nanoprecipitation method. The temperature-responsive TNPs efficiently encapsulated RG in aqueous solutions (without any organic solvents), thus improving the cellular uptake and skin-penetration ability of RG. The loading content of RG in TNPs was optimized by monitoring the changes in the physicochemical properties of the RG-loaded TNPs (RG@TNP). The optimally loaded RG@TNP showed long-term stability under physiological conditions, with better skin-penetration ability than free RG. In clinical trials, the RG@TNP showed excellent anti-aging effects on eye wrinkles; it improved skin elasticity and reduced skin pigmentation and sagging, indicating a massive potential in the cosmetic industry. The results obtained in this study confirm the ability of TNPs to efficiently encapsulate peptides with anti-wrinkle properties that improve their stability and skin-penetration ability.