> ## Content Index
> Fetch the complete content index at: https://www.fdaweb.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# Assessing Adhesion with Transdermal Systems
- URL: https://www.fdaweb.com/assessing-adhesion-with-transdermal-systems/
- Published: 2023-04-12T12:00:00.000Z
- Updated: 2026-09-14T18:25:17.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5154196

FDA has published a draft guidance, *Assessing Adhesion with Transdermal and Topical Delivery Systems for ANDAs*, with recommendations for the design and conduct of studies evaluating the adhesion performance of a transdermal or topical drug delivery system (TDS). The [document](https://www.fda.gov/regulatory-information/search-fda-guidance-documents/assessing-adhesion-transdermal-and-topical-delivery-systems-andas-draft-guidance-industry?ref=fdaweb.com) says its recommendations relate to studies submitted in support of an ANDA. Depending on the objectives of a generic TDS product development program, applicants may choose to evaluate TDS adhesion in studies performed to evaluate TDS adhesion only, or in studies performed with a combined purpose.

This guidance revises a 10/2018 draft guidance with the same title by clarifying the appropriate methods for measuring the estimated percentage of the entire TDS surface area adhered to the skin and the statistical analysis of that data. The revision also clarifies that the use of photographic evidence is not intended for automated or photometric analysis at this time, but can be used to support the visual observation of percent adhesion reported at each time point.