Effective Transcutaneous Delivery of Hyaluronic Acid Using an Easy-to-Prepare Reverse Micelle Formulation

The skin loses its moisture with advancing age, causing cosmetic issues such as wrinkles. In addition, the loss of moisture leads to hypersensitivity to external stimuli such as UV light. Transcutaneous supplementation with hyaluronic acid (HA) is an effective and safe method of recovering the moisturizing function and elasticity of the skin. However, the transcutaneous delivery of HA remains challenging owing to the barrier function of the stratum corneum (SC) layer. To penetrate the SC barrier, we used a reverse micelle formulation that does not require high energy consumption processes for preparation. We aimed to enhance the skin permeability of HA by incorporating glyceryl monooleate—a skin permeation enhancer—into the formulation. A fluorescently-labeled HA-loaded reverse micelle formulation showed significantly enhanced permeation across Yucatan micro pig skin. Fourier transform infra-red spectroscopy of the surface of the skin treated with the reverse micelle formulation showed blue shifts of the CH2 symmetric/asymmetric stretching peaks, indicating a reduction in the barrier function of the SC. Further study revealed that HA was released from the reverse micelles at the hydrophobic/hydrophilic interface between the SC and the living epidermis. The results demonstrated that our reverse micellar system is an easy-to-prepare formulation for the effective transcutaneous delivery of HA.