Enhanced skin penetration of 10-hydroxy-2-decenoic acid via anionic polymer formulations and skin hydration modulation

This study investigated strategies to improve the skin penetration of 10-hydroxy-2-decenoic acid (10H2DA), a bioactive unsaturated fatty acid derived from royal jelly with potential cosmetic and therapeutic value. Because the stratum corneum strongly limits the penetration of active compounds, the authors developed formulations containing anionic cross-linked polymers, including acrylates/C10–30 alkyl acrylate crosspolymer and carboxyvinyl polymers. Using Franz diffusion cells, Strat-M membranes, ex vivo human skin, LC-MS/MS analysis and DESI imaging mass spectrometry, they showed that these polymer-based formulations markedly enhanced 10H2DA permeation, achieving more than a tenfold increase compared with control royal jelly extracts. DESI-IMS further confirmed that 10H2DA penetrated beyond the stratum corneum into the epidermis. In a clinical tape-stripping study, higher skin hydration strongly correlated with greater 10H2DA penetration. Overall, the work demonstrates that both formulation design and skin hydration status are critical determinants of dermal delivery efficiency.