Transdermal delivery of cosmetic ingredients using dissolving polymer microneedle arrays

The efficiency of transdermal delivery of cosmetic ingredients is often limited by the outer layer of the skin, known as the stratum corneum, which can prevent diffusion of the cosmetic ingredients through the skin. A polymer microneedle array that dissolves in the skin can enhance the permeability of the skin to cosmetics. In this study, we prepared a polydimethylsiloxane (PDMS) mold to fabricate a microneedle array using laser-writing process which is a very simple and efficient method compared to conventional methods for preparing molds. Polyvinylpyrrolidone (PVP) and adenosine were used as a base material for the dissolving microneedles and a model cosmetic compound, respectively. Poly(ethylene glycol) dimethacrylate (PEGDMA) was copolymerized with PVP to control the properties of microneedles such as mechanical strength and solubility. PVP microneedle array was sufficiently sharp and with enough mechanical strength to create a transdermal pathway through the skin. The dissolution rate of the needle decreased with increasing PEGDMA content in the microneedle of PVP-PEGDMA copolymer. When adenosine was applied to the skin with the microneedle array, skin permeability to adenosine was improved by 150% compared to the control (without a microneedle array). These results indicate that the PVP microneedle array developed in this study has a potential to be used in cosmetics by combining with conventional cosmetic patches.