This article explores the challenges and solutions in the development of orally inhaled drug products (OIDPs). It discusses the need for alternative bioequivalence pathways and the importance of in vitro studies that measure the local rate and extent of absorption of a representative lung dose. The article also introduces Nanopharm’s next-generation, patented, aerosol dose collection apparatus that can harmonize both in vitro dissolution and in vitro release testing of OIDPs. This innovative approach removes the guesswork and provides pharmaceutical partners with an unprecedented level of confidence in their data. The article further discusses the concept of microstructural Q3 equivalence testing for locally acting products, essentially increasing the evaluation of pharmaceutical equivalence through physicochemical and functional product characteristics.