Q3 considerations for in situ forming implants: an in vivo evaluation of particle size effects

Diane Burgess – DISTINGUISHED PROFESSOR, The University of Connecticut; Qi Li – Contracting Officer’s Representative, FDA U.S Food and Drug Administration; Bin Qin – Senior Staff Fellow, FDA U.S Food and Drug Administration; Yan Wang – Deputy Division DIrector, FDA U.S Food and Drug Administration

Introduction: In situ forming implants (ISFIs) are complex long acting injectables with performance governed by complex physical, chemical, and biopharmaceutical attributes. In generic drug development, Q1 refers to qualitative sameness of components and Q2 to quantitative sameness of their amounts of inactive ingredients, while Q3 refers to physicochemical and structural similarity of the final product. This study focuses on API particle size as a Q3 consideration evaluating impact on depot formation, degradation, and in vivo pharmacokinetics of risperidone in situ forming implants with the aim of supporting generic drug development.