API Heterogeneity in a Multilayered Transdermal Patch

Transdermal patches are a popular route for drug delivery because of the sustained drug levels, low side effects, reduced hepatitic first-pass effect and ease of use, including self– administration. The basic components of any transdermal delivery system include one or more active pharmaceutical ingredient s (APIs) dissolved or dispersed in a reservoir or inert polymer matrix; an outer backing film of paper, plastic, or foil; a pressure-sensitive adhesive that anchors the patch to the skin; and a release liner, protecting the adhesive before application.