RT Journal Article
SR Electronic
T1 Microneedle coating methods: a review with a perspective
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP jpet.119.258707
DO 10.1124/jpet.119.258707
A1 Rohan Ingrole
A1 Harvinder Gill
YR 2019
UL http://jpet.aspetjournals.org/content/early/2019/06/07/jpet.119.258707.abstract
AB A coated microneedle array comprises of sharp micron-sized needle shafts that are coated with a drug on their surface and are attached to a base substrate. Coated microneedles have been used for drug delivery in to the skin and other tissues. A broad assortment of active materials including small molecules, peptides, proteins, deoxyribonucleic acids, and viruses have been coated onto microneedles. To achieve these coating on microneedles, different coating methods have been developed. Some of these methods can selectively coat just the microneedle shafts, while the other methods coat not only microneedle shafts but also the base substrate of the microneedle array. Methods that selectively coat just the microneedle shafts are most desirable since they provide control over drug dosage, prevent drug wastage, and offer high delivery efficiencies. The importance of measuring and reporting drug delivery efficiencies from coated microneedle systems is highlighted in this review. Different excipients are added to the coating liquid to modulate its viscosity and surface tension so that uniform coatings can be obtained on microneedles. Coated microneedles have been used in a broad range of biomedical applications. To highlight these different applications, a table summarizing the different active materials and their amounts coated on microneedles is provided. We also discuss factors that should be considered when deciding suitability of coated microneedles for new drug delivery applications. In recent years, many coated microneedles have been investigated in human clinical trials and there is now a strong effort to bring the first coated microneedle-based product to market.SIGNIFICANCE STATEMENT Different methods have been developed to coat microneedles with drugs. Some methods are better able to control where on the microneedle array the drug-coating gets deposited. Methods that selectively coat just the microneedle shafts are most desirable since they provide control over drug dosage, prevent drug wastage, and offer high delivery efficiencies. Although coated microneedles have primarily been used for vaccination, nonetheless, they have also been investigated for the treatment of other indications such as allergy, anemia, type 2 diabetes and cancer. Coated microneedles are increasingly being evaluated in humans, suggesting that an FDA approved treatment based on coated microneedles may soon be commercially available.