Out-of-plane cup shaped stainless steel microneedle array for drug delivery

To improve the transdermal delivery of drug, there are many techniques have been reported (Chemical, Iontophoresis, Sonophoresis and Microneedle). Among these techniques, the microneedle technology gained the more attention in recent years. Mainly, there are two types (Solid and Hollow) of microneedles have been reported for the successful drug delivery application. In this paper, we report on the fabrication of out-of-plane solid Stainless Steel (SS) microneedles and formation of microcup structure within them suitable for drug delivery application. Array of out-of-plane solid SS microneedles were fabricated using Electric Discharge Machining (EDM) method. Subsequently, the microcup structures on the solid SS microneedles were formed using Focused Ion Beam (FIB) technique. The microcup structure on the microneedles acts as a dedicated region to fill the drug, so that the possible drug leakage while inserting the microneedles into the skin can be avoided. The drug filling into the microcup structures was performed using drop coating method. This coating method in combination with cup shaped microneedle array enables to deliver multiple drugs simultaneously in desired proportion.