The U.S. Food and Drug Administration (FDA) has announced a funding opportunity aimed at developing physiologically based pharmacokinetic (PBPK) model-based mechanistic in vitro-in vivo correlations (IVIVCs) for long-acting injectables (LAIs), specifically crystalline suspensions and polymer-based implants. The objective is to create a PBPK model that incorporates critical formulation attributes to better predict in vivo drug release mechanisms, thereby enhancing the understanding of pharmacokinetics and variability in transitioning from animal models to human predictions. This initiative is crucial for addressing gaps in the pharmacokinetic profiles of LAIs and supporting the development of generic products. Interested applicants, including higher education institutions and nonprofits, can apply for up to $600,000 in funding for two awards, with applications due by April 8, 2024. For further details, contact Terrin Brown at terrin.brown@fda.hhs.gov or visit the funding announcement at https://grants.nih.gov/grants/guide/rfa-files/RFA-FD-24-006.html.