Physicochemical and Structural (Q3) Characterization of Topical Drug Products Submitted in ANDAs March 2026

https://www.fda.gov/regulatory-information/search-fda-guidance-documents/physicochemical-and-structural-q3-characterization-topical-drug-products-submitted-andas?utm_medium=email&utm_source=govdelivery New Final Guidance for Industry: Physicochemical and Structural (Q3) Characterization of Topical Drug Products Submitted in ANDAs The Food and Drug Administration (FDA) published the final guidance for industry entitled “Physicochemical and Structural (Q3) Characterization of Topical Drug Products Submitted in ANDAs.” This guidance finalizes the draft guidance for industry of the same title issued on October 21, 2022. This final guidance is intended to assist applicants who submit abbreviated new drug applications (ANDAs) for liquid-based and/or other semisolid products applied to the skin, including integumentary and mucosal membranes, referred to as “topical products.” This final guidance provides recommendations for physicochemical and structural (collectively, “Q3”) characterizations that can be used to identify the dosage form of a proposed generic (test) topical product, and to describe properties of the drug product that may be critical to its performance (to support a demonstration of bioequivalence (BE)). This final guidance provides recommendations on the types of characterizations that constitute a basic and comprehensive Q3 characterization. This final guidance also describes the concepts of “sameness,” “similarity,” and “difference” in comparing Q3 characterizations of two topical products, and how showing “Q3 sameness,” “Q3 similarity,” or “Q3 difference” between a test topical product and the reference standard may impact what additional evidence may be recommended to demonstrate BE, as part of a comparative product characterization-based approach. This guidance does not address Q3 characterization of topical products for purposes of product quality control. As part of the Drug Competition Action Plan, FDA is publishing this guidance to increase competition in the marketplace for prescription drugs, facilitate the entry of high-quality and affordable generic drugs, and improve public health.