Transdermal Drug Delivery Devices Based on Microneedles: A Review

1) . Drug delivery systems (DDSs) use existing formulationsand op­ timize drug treatment in order to reduce adverse drug reactions, increase our body’s compliance, and maximize efficacy and ef­ fectiveness, via effective delivery of drug. DDSs are developed for purposes such as improved bioavailability and treatment efficacy, reduced adverse reactions, and increased patient compliance. DDSs are classified into oral administration, transdermal ad­ ministration, injection, pulmonary inhalation, and transmucosal administration, based on route of administration. Among these, transdermal administration is most commonly used because of its low level of patient discomfort and ease of use. The attempt to deliver drug through the skin has a long history, as the skin accounts for the largest area of the human body. However, early transdermal drug delivery (TDD) systems were attempted for localized action on a damaged area, because the skin had been perceived as alayer impenetrable to drugs, protecting the human body against the invasion of various harmful substance, microor­ ganisms, or chemical substance. However, development of TDD systems accelerated, as the Transderm­Scop patch, a painkiller, developed for administration of scopolamine, was approved by FDA in 1979