Toxicokinetic Differences and Toxicities of Silver Nanoparticles and Silver Ions in Rats After Single Oral Administration

Abstract

Blood levels, tissue distributions, and excretion of silver (Ag) were measured in male Sprague-Dawley rats (n = 5) up to 24 h after a single oral administration of silver nanoparticles (AgNP) and silver ions (Ag⁺), respectively. The AUC_24hr of Ag⁺ was 3.81 ± 0.57 μg/d/ml when rats were treated with a single dose of 20 mg/kg, whereas that of AgNP was 1.58 ± 0.25 μg/d/ml. Tissue distribution of Ag in liver, kidneys, and lungs was higher when Ag⁺ was administered compared to AgNP. Orally administered AgNP were predominantly excreted through feces, suggesting low bioavailability. Death or body weight changes were not observed in the Ag⁺- or AgNP-treated groups. However, decreased red blood cell counts, hematocrit, and hemoglobin were found in the Ag⁺-treated groups, while increased platelet counts and mean platelet volume were noted in the AgNP-treated rats. A serum biochemical analysis showed that aspartate aminotransferase (AST) and alanine aminotransferase (ALT) rose significantly following Ag⁺ treatment (20 mg/kg). AgNP treatment (2 or 20 mg/kg) also elevated AST, whereas infiltration of mononuclear cells with liver necrosis was found only in the 20 mg/kg Ag⁺-treated animals.

Acknowledgments

Technical assistance in animal care by Chemon, Inc., and silver analysis by KBSI are acknowledged.