FDA-2018-D-3546 for “Assessing the Irritation and Sensitization Potential of Transdermal and Topical Delivery Systems for ANDAs.” The Food and Drug Administration (FDA or Agency) is announcing the availability of a revised draft guidance for industry titled “Assessing the Irritation and Sensitization Potential of Transdermal and Topical Delivery Systems for ANDAs.” This draft guidance replaces the draft guidance “Assessing the Irritation and Sensitization Potential of Transdermal and Topical Delivery Systems for ANDAs” (April 2023). BackgroundFDA is announcing the availability of a revised draft guidance for industry titled “Assessing the Irritation and Sensitization Potential of Transdermal and Topical Delivery Systems for ANDAs.” The draft guidance, when finalized, will represent the current thinking of FDA on “Assessing the Irritation and Sensitization Potential of Transdermal and Topical Delivery Systems for ANDAs.”