Marine polymeric microneedles for transdermal drug delivery

Transdermal drug delivery is considered one of the most attractive routes for administration of pharmaceutic and cosmetic active ingredients due to the numerous advantages, especially over oral and intravenous methodologies. However, some limitations still exist mainly regarding the need to improve the drugs permeation across the skin. For this, several strategies have been described, considering the application of chemical permeation enhancers, drugs' nanoformulations and physical methods. Of these, microneedles have been proposed in the last years as promising strategies to enhance transdermal drug delivery. In this review, different types of microneedles are described, and the most commonly used methods of fabrication systematized, as well as the materials typically used and their main therapeutical applications. A special attention is paid to polymeric microneedles, particularly those made from sustainable marine polysaccharides like chitosan, alginate and hyaluronic acid. The applications of marine based polymeric microneedle devices for transdermal drug delivery are examined in detail and the perspectives of translation from the clinical trials to the market demonstrated.