On November 22, FDA released the new draft guidance for “Transdermal and Topical Delivery Systems (TDS) – Product Development and Quality Considerations”. This is a useful guide to help the industry to deal with the complexity of the transdermal delivery system or patch and the associated challenges related to product development.

https://www.fda.gov/regulatory-information/search-fda-guidance-documents/transdermal-and-topical-delivery-systems-product-development-and-quality-considerations