Extrapulmonary distribution of65Zn post-IT instillation of65ZnO and SiO
-coated65ZnO NPs. Data are % of instilled dose recovered in all secondary tissues examined. It included blood, thoracic lymph nodes, bone, bone marrow, skin, brain, skeletal muscle, testes, kidneys, heart, liver, and the gastrointestinal tract. There was a rapid absorption and accumulation of 65Zn in secondary tissues. At day 2, 59-72% of the dose was detected in extrapulmonary organs. Then, 65Zn levels decreased over time to 25-37% by day 28. Significantly more 65Zn was detected in secondary organs at all time points in rats instilled with uncoated 65ZnO NPs.