The tissue partition, maternal-fetal transfer and physiologically based pharmacokinetic modelling for silver nanoparticles exposure in pregnant rats.

To date, only a few studies have investigated the biodistribution and kinetics of silver nanoparticles (AgNPs) throughout pregnancy. In this study, pregnant rats were repeatedly exposed to 20 nm and 30 nm polyvinylpyrrolidone-coated AgNPs via intravenous (IV) or oral gavage for 20 days. Results indicated that AgNPs primarily accumulated in the spleen, kidneys, and liver, with silver concentrations ranging from 0.58 to 75.07 μg/g dry weight (dw) across all treated groups. IV exposure resulted in 1.43- to 80.87-fold greater tissue accumulation compared to oral exposure. The liver and kidneys accounted for 11.9-37.2 % and 4.7-21.9 % of the total body burden of silver, respectively. The average size of silver-containing particles in the maternal liver, spleen, and kidneys ranged from 55.15 to 268.55 nm. Silver concentrations in the placenta and fetuses were 1.92-34.94 μg/g dw and 0.95-5.16 μg/g dw, respectively. The placenta effectively limited the transfer of AgNPs to the fetus. Furthermore, physiologically based pharmacokinetic models were successfully developed for both exposure routes, with R2 values of 0.81-0.99 and the root mean squared error (RMSE) value of 0.24-4.41. These findings provide valuable insights into the biodistribution and maternal-fetal transfer of AgNPs during gestation.