MICRONEEDLES: AN EMERGING TECHNOLOGY FOR THE EFFECTIVE TRANSDERMAL DRUG DELIVERY

Topical drug delivery is the conventional route of drug administration to the surface of the skin. Barrier present in the various layers of skin hinders the permeability of drug molecules, specifically large size of drug substance into the systemic circulation. A small-sized needle in micron range is found to be a promising approach to penetrate the uppermost layer of the skin i.e., epidermis to the dermal tissue. These needles are used in the delivery of drugs such as insulin, proteins, RNA and gene therapy due to the efficiency, convenience, safety, and painless nature of the needle. Moreover, the combination of non-carriers with the microneedle delivery system further highlights the application of these needles. This review will discuss the various types of microneedles (MNs) such as coated, solid, dissolving hollow and hydrogels for the effective delivery of drugs and the materials used as fabrication of microneedles. All the microneedles act differently to show its action such as solid MNs produce mini pores in the skin, whereas special channels will be formed into the dermal layer by the hollow MNs and dissolving MNs have explored their role in the delivery of vaccines. It possesses varied characteristics and has applications according to the material used in their formation. This review also focuses on the background, recent trend and summarization of its type along with applications.