Disposition of indium in male Fisher-344 rats following intratracheal or oral administration of the III-V intermetallic semiconductor material, indium phosphide

Abstract

A sensitive method measuring indium levels >1 ppb (ng/ml) in biological tissues was developed using graphite furnace atomic absorption spectrophotometry. Single oral and pulmonary exposure of uniformly sized indium phosphide particles (mean count diameter = 1.73 ± 0.85 μm) to rats at three dose levels. Indium was deposited throughout tissues after 4 days. Bone, hair, skin, liver and kidney contained the largest indium concentrations (ng Indium/gram tissue) in both studies. Total percent dose found in tissues by either route resulted in an estimated absorption of <0.5% (not including lung for pulmonary study) except in the oral low dose group. Here the percent dose found in tissues was about 5.0% of the administered dose. The lung retained >50% of the administered dose four days following intratracheal instillation. The major route of indium elimination for both oral and pulmonary studies was in the feces; >78% of the administered dose by two days following oral gavage and >26% of the administered dose following intratracheal instillation.