In vitro solubility and in vivo toxicity of indium phosphide

This study was designed to clarify the in vitro solubility and the in vivo basic toxicity of indium phosphide (InP). InP powder was clearly soluble in synthetic gastric fluid and quite insoluble in saline or synthetic lung fluid. Male ICR mice (SPF grade) were given InP at the doses of 0, 1,000, 3,000, and 5,000 mg/kg, intraperitoneally (i. p.) or orally (p. o.). During a 2-week observation, no mice died. In i. p. treated mice, the serum indium concentration showed a dose-dependent increase, and indium mainly accumulated in the lungs and liver. Dose-dependent increases in lung and spleen weight were observed. Black granules of InP were deposited in the lymph nodes, spleen, lungs, and liver. Extramedullary granulopoiesis was observed. And eosinophilic exudates and mononuclear cells were seen in the pulmonary alveoli. Considering these findings, InP particles were presumably transferred to the spleen, liver, and lungs by way of lymphokinetics, causing reticuloendothelial responses. Hematological examination showed increased proportions of stab cells and monocytes in 5000 mg/kg i. p. dosed mice. The p. o. administered mice showed no clear relationship between the dose and biological effects.