We excel at nanoparticle modeling. These new categories of drugs are a unique beast. They are not classical small molecules nor have protein kinetics. They can vary among them, depending on their overall size, charge, or payload. To sum up, nanomedicines are each time a new species of drug. This sparks peculiar and unpredictable plasma and tissue kinetics that must be evaluated each time. Modeling is perhaps even more necessary to understand the mechanism of absorption, disposition, and elimination of particles. Some of them have flip-flop kinetics (like implants), other nanoparticle drugs circulate with their own specific fate. Regulators are very wary about the safety of these products and modeling should always be there to reassure them. Modeling is a real money saver.