Transdermal delivery of biopharmaceuticals: dream or reality?

The skin being the largest organ of the body presents a potential route for administration of drugs. Passive transdermal products such as gels, creams and patches deliver drugs effectively across the skin. However, this approach is limited to lipophilic molecules with low molecular weights. Passive transdermal delivery of proteins and peptides which are hydrophilic with high molecular weights is negligible. This led to the development of various ways of surmounting the skin barrier so as to make this route feasible for peptide and protein delivery. The current article reviews various active transdermal technologies with special emphasis on microneedle mediated delivery. Microneedles, especially dissolvable microneedles present an excellent platform for protein and peptide delivery. Significant advances have been made in the past decade in this area. Published literature shows a broad spectrum of molecules being delivered successfully via microneedles. However, success in clinic will give a boost to all the efforts and advances made in this field so far.