Synthesis and characterization of the metal coated PVP microneedle patch for drug delivery system using thermal or electrical stimulation

Abstract

A conventional microneedle patch has the disadvantages of weak mechanical properties and low drug-release efficiency when using polymers such as hyaluronic acid, chitosan, cellulose, and polycaprolactone. In this study, we prepared a novel microneedle patch using metal bioelectrodes that provide excellent mechanical properties, drug-delivery efficiency, and biocompatibility at the same time. This biocompatible polyvinylpyrrolidone (PVP) based hydrogel-type microneedle patch was prepared using gamma rays to compensate for its weak mechanical properties. The back side of the PVP based microneedle patch were coated with gold or silver (which provides excellent thermal and electrical conductivity) as bioelectrodes using the thermal evaporation method to maximize or control the efficiency of drug release. The metal (Au or Ag)-coated microneedle patch has enough mechanical properties to successfully penetrate the skin. Even after being fixed to the skin, the shape of a needle tip was hardly deformed, and exhibited resistance to breakage even when bent due to its flexibility. In addition, it was confirmed using a Franz cell that the amount of drug released from a drug-loaded microneedle patch was maximized by thermal or electrical stimulus. The drug-release efficiency increased more than 7.9 times (790%) compared to a flat PVP patch (without applying electricity) when 3 V was applied. In addition, when ~ 40 ℃ heat were applied, the drug-release efficiency of the Au- and Ag-coated PVP based microneedle patches improved about 5.3 times (530%) compared to a flat PVP patch at room temperature. These excellent properties of our metal-coated PVP based microneedle patches can be used not only in whitening or anti-wrinkling cosmetics, but also as medical drug-delivery systems to treat such as hypertension, diabetes, and arthritis.