Considerations in the use of microneedles: pain, convenience, anxiety and safety.

Transdermal delivery using microneedles is gaining increasing attention from pharmaceutical and cosmetic companies as one of the promising drug delivery methods. Microneedle products have recently become available on the market, and some of them are under evaluation for efficacy and safety. To be available in the market for cosmetic and therapeutic use, several factors should be considered, including pain, anxiety, convenience and safety. These factors are summarized and reviewed in this article according to type of microneedle. Various kinds of materials have been used for manufacturing microneedles and developing drug formulations for microneedles. Safety information about materials used for microneedles is summarized in terms of type of microneedles. In addition to their biocompatibility, mechanical safety is also discussed. This review can provide guidelines for designing microneedle products for proper use.