Addressing Challenges, Regulatory Shifts, and the Need for Cost-Effective Alternatives for Complex Topical Formulations.

Topical dosage forms are widely used to treat various skin disorders, but increase healthcare costs because of the limited number of generic competitors. The development of a generic version of complex topical products is facing several scientific and regulatory challenges related to demonstrating bioequivalence, advanced physicochemical characterization, and the requirement of clinical endpoint equivalence. This narrative review explores the contemporary scientific and regulatory approaches used for BE assessment of topical generics, with a greater focus on in vitro alternatives and Q3 microstructural characterization. The integration of quality by design principles can support the development of robust Q3-based BE strategies. Key in vitro tools such as IVRT, IVPT, and dermal PBPK modeling are emerging approaches for identifying scientific parameters for regulatory acceptability and overcoming these methodological challenges. Case studies involving bifonazole, acyclovir, clotrimazole, and innovative vehicles such as Recura illustrate the practical challenges of existing regulatory frameworks and the increasing use of in vitro and Q3-based approaches. This review highlights the critical gaps in harmonizing global regulatory requirements and underscores the need to foster early regulatory engagement and standardize methodological protocols. Together, these initiatives pave the way for a more predictable, scientifically sound, and cost-effective regulatory environment. This transformation is essential for improving access, reducing development timelines, and advancing the future of topical generic medicines.