Endocytosis mechanism in physiologically-based pharmacokinetic modeling of nanoparticles.

Abstract

BACKGROUND\nThe physiologically based pharmacokinetic (PBPK) model is a useful tool to predict the pharmacokinetics of various types of nanoparticles (NPs). The endocytosis mechanism plays a key role in pharmacokinetics of NPs. However, the effect of endocytosis mechanism both in the blood and tissue are seldom considered in PBPK model.\n\n\nOBJECTIVES\nTo investigate the biodistribution of intravenously injected pegylated AuNPs in mice and human using PBPK model considering the endocytosis mechanism both in the blood and tissue.\n\n\nMETHODS\nTaking polyethylene glycol-coated gold nanoparticles (AuNPs) as an example, we developed a PBPK model to explore biodistribution of different size AuNPs. In the model, we considered the role of endocytosis mechanism both in the blood and tissue. In addition, the size-dependent permeability coefficient, excretion rate constant, phagocytic capacity, uptake rate, and release rate were derived from literatures. The mice PBPK model was extrapolated to the human by changing physiology parameters and the number of phagocytic cell (PCs).\n\n\nRESULTS\nAuNPs were primarily distributed in the blood, liver, and spleen regardless of particle size, and almost all captured by the PCs in the liver and spleen, while few was captured in the blood. There are more organ distribution and longer circulation for smaller NPs. The 24-h accumulation of AuNPs decreased with increasing size in the most organ, while the accumulation of AuNPs showed an inverted U-shaped curve in the liver and slight U-shaped curve in the blood. The human results of model-predicted displayed a similar tendency with those in mice. Size, partition coefficients, and body weight were the key factors influencing the organ distribution of AuNPs.\n\n\nCONCLUSIONS\nThe size played an important role on the distribution and accumulation of AuNPs in various tissues. Our PBPK model was well predicted the NPs distribution in mice and human. A better understanding of these mechanisms could provide effective guides for nanomedine delivery.