Abstract
Microneedle (MN) technology has recently attracted considerable attention as an effective means of transdermal delivery with a high degree of safety. Clinical research is focusing especially on MN containing influenza vaccine or insulin. Generally, MN can be divided into two types, a solid type consisting of silicon or stainless material, and a self-dissolving type made mainly from biodegradable materials, such as hyaluronic acid (HA) or saccharides. All of them have multiple micro-projections to deliver agents into cutaneous tissue, with a pinholder pattern on the patch. We evaluated the efficacy of self-dissolving MNs made of HA for cosmetic use, focusing on their solubility in stratum corneum (SC). We found that continuous administration of MN at the eye corner resulted in significant increases of the water content of the SC and of skin elasticity. These findings suggested that this might be an effective approach for cosmetic improvement of wrinkles. MN was launched as‘NAVISION HA fill-patch’ on March 2011 as an anti-wrinkle cosmetic. Here, we review the efficacy of self-dissolving MN, the effect of HA on cutaneous cells, and the mechanism of wrinkle formation.
