Potential of biocompatible polymeric ultra-thin films, nanosheets, as topical and transdermal drug delivery devices

The aim of the present study was to assess the potential of biocompatible polymeric nanosheets as topical and transdermal drug-delivery devices. Nanosheets are two-dimensional nanostructures with a thickness in the nanometer order, and their extremely large aspect ratios result in unique properties, including high transparency, flexibility, and adhesiveness. Nanosheet formulations containing betamethasone valerate (BV) as a model drug and consisting of poly (L-lactic acid) or poly (lactic-co-glycolic) acid were fabricated through a spin-coating-assisted layer-by-layer method using a water-soluble sacrificial membrane. The fabricated formulations could incorporate and release higher amounts of BV compared with a commercial ointment, and the amounts could be controlled by the polymers used, the amount of BV added, and the use of controlled-release membranes. The presence of BV had a minimal effect on thickness, transparency, adhesiveness, and moisture permeability of nanosheets, permitting their application to any area of skin for a long period of time. Therefore, this biocompatible polymeric nanosheet formulation represents a novel and promising topical and transdermal drug delivery device, which has potential to deliver drugs regardless of the area of skin.