“…Experimental methods for measuring the extent of plasma protein binding or fraction unbound (f u ) rely on long-established techniques for separating bound and unbound drug (Rowland, 1980). Until further research validates novel methods for simulating protein binding behavior of NP constituents, determining f u experimentally is recommended based on data generated by the NaPDI Center (Nguyen et al, 2019). In brief, f u for multiple NP constituents (n = 14-17) in human liver microsomes (HLMs) and plasma was generated in silico using two modeling and simulation platforms (www.certara.com, v17; Simcyp and www.simulations-plus.com/software/gastroplus, v9.6; Gas-troPlus) and compared with experimentally determined values.…”