Performance testing of mucosal drug products presents the user with a multitude of challenges. Not only are there many different dosage forms to be distinguished, but also a wide variety of administration routes. The target action effect (local or systemic) is another factor to be considered. Thus, it quickly becomes apparent that there will never be a universal performance test, but the question arises just as quickly whether the method to be used should rather depend on the dosage form or the place of application, or even whether decisions must be made on an individual basis. This Stimuli article is one of a series of Stimuli articles on product performance testing, which focuses on methodological approaches and challenges in the field of performance testing of mucosal drug products. The article should be viewed as a supplement to, but also a critical discussion of the methods listed in USP general chapter Mucosal Drug Products—Performance Tests 〈1004〉. With consideration of major physiologic aspects at the site of administration and the types of dosage forms to be studied, limitations of the methods described here and the need for methodologic updates or innovations are identified. Furthermore, suggestions are made for future activities, all aimed at developing robust, discriminatory, and meaningful test methods for the wide variety of mucosal drug products.
