Microneedles and their applications

Microneedle mediated microporation has proved its potential to enhance the delivery of therapeutic drug molecules through skin over the last one decade. Several patents have been granted and cutting edge research is going on particularly for the delivery of biopharmaceuticals (macromolecules like protein or peptides). The technology involves use of micron sized needles made of diverse materials to form microchannels into the stratum corneum (or deeper), outermost barrier layer of the skin. These microchannels are deep enough to facilitate efficient drug delivery through disrupted stratum corneum but short enough to avoid bleeding or pain. So far, the microneedle technology has been explored for drug and vaccine delivery through transcutaneous route. However, the miniaturized nature of these microneedles and anticipated minimal invasiveness has led the scientists to explore and patent its possible use for several other applications.The use of this technology in combination with other enhancement techniques has also gained recent attention. This review article focuses on the latest developments in the field of microneedles as described in patent and research literature. Comprehensive review of several topics including device design/fabrication, formulation development, safety/regulatory issues, therapeutic applications and major challenges in the commercialization of microneedles as medical devices has been presented here.