Oral Toxicity of Indium in Rats: Single and 28‐Day Repeated Administration Studies

Abstract

Oral Toxicity of Indium in Rats: Single and 28-Day Repeated Administration Studies: Keiko ASAKURA, et al. Department of Preventive Medicine and Public Health, Keio University School of Medicine-Indium is widely used in the electronics industry to make semiconductors, liquid-crystal panels, and plasma display panels, and its production is increasing. However, it is necessary to handle it more cautiously than before, because the pulmonary toxicity of inhaled indium has been identified. The present study aimed to characterize the potential toxic effects of indium through oral administration and observation for fourteen days following a single dose of 0 or 2,000 mg/kg (acute oral toxicity study), and repeated oral administration for 28 days at dose levels of 0, 40, 200, or 1,000 mg/kg daily (28-day repeated oral dose toxicity study) to male and female Crj:CD (SD) IGS rats (SPF). No deaths and no abnormalities in clinical signs, body weights, and necropsy findings were observed for any of the animals in the acute oral toxicity study. Furthermore, no changes related to indium were also observed in the dose groups up to 1,000 mg/kg of the 28-day repeated oral dose toxicity study. From the results described above, the lethal dose 50% (LD 50 ) of indium is greater than 2,000 mg/kg under these study conditions, and the no-observed-adverse-effect-level (NOAEL) is considered to be 1,000 mg/kg for males and females under these conditions. (J Occup Health 2008; 50: 471-479)

Studies on the Toxicity and Distribution of Indium Compounds According to Particle Size in Sprague-Dawley Rats

“…Even with the widely accepted assumption that smaller particles (i.e., nanomaterials) are more toxic, appropriate remains questionable (19). Lastly, most of toxicological data from hazard assessments to date were generated using larger particles, although indium compounds (especially indium-tin oxide) are produced at the nano-scale (2,20-24). Therefore, this study was performed to investigate the toxicity and distribution of indium compounds according to their particle size and chemical composition to fill the knowledge gap concerning the hazards of indium compounds.…”

ICRP Publication 151: Occupational Intakes of Radionuclides: Part 5

“…In vivo, gastrointestinal absorption in rats was <1%. Asakura et al. (2008) observed no toxicity of indium metal administered orally to rats with a single dosage of 2 g kg −1 or a repeated oral dose of 1 g kg −1 daily for 28 d. Andersen et al.…”

“…In vivo, gastrointestinal absorption in rats was <1%. Asakura et al (2008) observed no toxicity of indium metal administered orally to rats with a single dosage of 2 g kg À1 or a repeated oral dose of 1 g kg À1 daily for 28 d. Andersen et al (2017) studied the invitro dissolution of indium-tin oxide (ITO) powder in a simulated gastric environment, and observed the release of <0.1% indium from the ITO powder over 4 h. After 60 d of mouse gavage with metal salts of bismuth, indium, and ruthenium, Laval et al (2018) observed similar ratios of In 3þ and Bi 3þ concentration in serum to the orally given amount. Ingested materials § All forms 0.005 * It is assumed that the bound state can be neglected for indium (i.e.…”

Use of Bioelution as a Screening Tool for Characterisation of Substances

“…The result of the study with rat on In metal powder [46] was considered conclusive. For the other indium compounds under consideration in the consortium, no experimental data were available, and no further animal testing was conducted.…”