Microneedles: From Micromachining To Transdermal Drug Delivery Swarnlata Saraf*, Deepankar Gupta, Chanchal Deep Kaur, Shailendra Saraf A R T I C L E I N F O ABSTRACT Keywords: Review Article Microneedles Skin penetration Microfabrication Transdermal drug delivery 1. Introduction Electronic devices have reached a stage of dimension comparable to those of biological macromolecules. This raises exciting possibilities for implication of microelectronics technology in drug delivery by microfabrication and nanofabrication of the drug delivery devices. Microneedles are new transdermal drug delivery technique designed to create holes in the epidermis and penetrate the stratum corneum, thus avoiding the high resistance of this barrier. Microneedles are produced by employing micromachining or micro- electromechanical systems technology, which is used for manufacturing the integrated circuits. Microfabrication helps in fabricating the microneedles in various ranges of sizes and shapes with the desired strength for easy insertion into the skin. Microneedles combine the advantages of conventional injection needles and transdermal patches while minimizing their disadvantages. These are safer and painless alternative to hypodermic needle injections for various biomedical applications such as blood sampling and delivery of drugs especially for protein biotherapeutics and vaccines. Microneedles can pierce holes into the skin to increase transport by diffusion or act as drug carriers that release drug into the skin from a microneedle surface coating. Microneedles can be used for the delivery of genetic material for gene expression and gene therapy. They could also be used for targeting of the bioactive for treating skin cancers. The outcome of this review is that microneedles represent a promising microfabricated device to deliver therapeutic compounds into the skin for a range of possible applications. Since times immemorial, mankind has been suffering from various diseases, for which they discovered drugs and various delivery systems to restore normalcy of life. Treatment of a chronic disease or acute illness has been done by delivering drugs using different dosage forms such as tablets, capsules, pills, emulsions, suppositories and many more. These conventional dosage forms though provide an instant release of drugs but to maintain the plasma concentration they have to be delivered several times in a day [1, 2]. Like in case of oral route, convenient and conventional modes for administering drugs, which allows self administration, but not for drugs like proteins and peptides which are unstable in gastric environment and unable to cross the gut wall .These conditions pose a threat of significant fluctuations in drug levels and poor patient compliance [3, 4].A closely monitored continuous intra-venous infusion is advantageous in controlling the plasma drug levels with direct entry of drug in the blood. But this needs to be complemented with close medical supervision and hospitalization [5, 6]. The controlled drug delivery formulations cater to this by delivering the right amount of drug, at right time, a prerequisite for optimal therapeutic effects without rigorous monitoring [7, 8]. As an extension to these novel formulations, transdermal drug delivery via microneedles is a viable option [9- 11]. The main advantage of microneedles over the hypodermic needles is that they do not cause pain on insertion [12] and unlike other transdermal drug delivery systems they can deliver a large number Copyright 2011. CurrentSciDirect Publications. IJCBPR - All rights reserved. c Contents lists available at CurrentSciDirect Publications Journal homepage: www.currentscidirect.com International Journal of Current Biomedical and Pharmaceutical Research Int J Cur Biomed Phar Res. 2011; 1(2): 80 – 87. CurrentSciDirect Publication University Institute of Pharmacy, Pt. Ravishankar Shukla University, Raipur (C.G.) 492010. * Corresponding Author : Dr. Swarnlata Saraf, Reader University Institute of Pharmacy Pt. Ravishankar Shukla University Raipur (C.G.) 492010. Tele Fax. +91 771 2262832 Email : , swarnlata_saraf@rediffmail.com chanchaldeep@rediffmail.cm Copyright 2011. CurrentSciDirect Publications. - All rights reserved. IJCBPR c