Back to: Navigating Controlled Correspondences to Support Generic Drug Development
Presenter
Ying Jiang, PhD
Chemist
Division of Therapeutic Performance I (DTP I)
Office of Research and Standards (ORS)
Office of Generic Drugs (OGD)
Center for Drug Evaluation and Research (CDER)
US Food and Drug Administration (FDA)
Abstract
This presentation, given by Ying Jiang during the 2025 Navigating Controlled Correspondences Webinar, provides general considerations and best practices for seeking feedback on inactive ingredients and formulations for generic drug products not required to be Q1/Q2 identical to the Reference Listed Drug (RLD). Using topical products as an example, it explains that differences in inactive ingredients are acceptable provided they are identified, characterized, and justified. The talk emphasizes the need to ensure the proposed level of inactive ingredients is acceptable, requiring Maximum Daily Exposure (MDE) assessment, and strongly encourages submitting early inquiries regarding MDE. A core focus is the No Significant Difference (NSD) formulation standard, frequently used in the characterization-based bioequivalence (BE) approach. It clarifies that the NSD standard permits certain differences based on scientific evidence while not accepting just any formulation. Key guidance is offered on submitting controlled correspondences (CCs), advising sponsors to ask about a formulation’s eligibility for a specific BE approach rather than its Q1/Q2 sameness. Detailed information is provided on essential Q1 and Q2 information to include in CC submissions, covering identity, quantity, details for mixtures, and compounding kits, to facilitate efficient assessment and avoid delays. Engaging early and providing comprehensive information through the CC program is highlighted as beneficial for generic drug product development.