Safety of Microneedles for Transdermal Drug Delivery

Abstract

Volume 6 • Issue 2 • 1000e172 J Pharmacovigil, an open access journal ISSN: 2329-6887 Transdermal delivery is an attractive route of administration, allowing the therapeutic agents to bypass first pass-hepatic metabolism to minimize the drug toxicity and enhance the treatment efficacy, especially for drugs that are unstable in the acidic environment in the stomach or those cause irritation in the gastrointestinal tract [13]. Despite these advantages, a drawback is observed in skin delivery: numerous drugs have extremely low skin permeability due to the outermost lipophilic stratum corneum layer of skin. Passive diffusion is generally limited to small molecules (molecular weight less than 500 Da) with a low dose (highly potent), and moderate lipophilicity (log P 1-3) [2-5]. The drug delivery can be enhanced by optimizing the drug formulations or disrupting the skin barrier function using either chemical penetration enhancers or physical enhancement technologies including microneedles, laser, sonophoresis, iontophoresis, and thermal energy [6,7]. Microneedles application is a minimally invasive, cost-effective, and patient-compliant technique to significantly enhance the drug delivery into and across skin [8-10]. Upon being inserted into the skin, microneedles disrupt the stratum corneum and penetrate the epidermis layer to create interstitial fluid-filled and micronsized channels in skin. These microchannels allow the penetration of therapeutic agents of any size (monoclonal antibody, vaccines, proteins and peptides, microparticles, and cosmeceuticals) [8,11-13] without causing irreversible damage to skin, irritation, or infection [14-16]. The safety of microneedles could be evaluated on various factors including pore closure, potential infection, risk of bleeding, local reactions, needle breakage, biocompatibility of needle materials, concerns related to microneedles reuse, and safe disposal.