Challenging Traditional ADME Assumptions for Physiologically Based Pharmacokinetic Models for Intravenous...

Intravenous iron-carbohydrate complexes are a class of nanomedicines that are widely used globally to treat iron deficiency and iron deficiency anemia associated with a wide spectrum of disease states. Despite being widely used in clinical practice for more than seven decades, the understanding of their in vivo disposition including tissue biodistribution and kinetics of the nanoparticle degradation at the cellular level is not well-understood. Moreover, the critical quality attributes that influence in vivo pharmacokinetics have not been fully defined. In particular, the carbohydrate moiety plays an influential role in how the nanoparticulate iron-carbohydrate complex interacts with the biological system. Developing a physiologically based pharmacokinetic (PBPK) model would facilitate a deeper understating of the key nanomedicine attributes that predict in vivo performance. Because endogenous iron metabolism complicates pharmacokinetic modeling for this complex class of drugs, models of gold nanoparticles may provide a substantive roadmap to begin to build a viable PBPK model for iron-carbohydrate nanomedicines. In the future, PBPK models that integrate recent mechanistic data regarding tissue biodistribution and intracellular iron kinetics for parameterization have the potential to improve manufacturing quality and clinical use of these complex drugs.