Pharmacokinetics of an indium-labeled IgG monoclonal antibody over a prolonged period.
This study was directed toward determining the pharmacokinetic fate of an IgG2a monoclonal antibody (MoAb). The 96.5 anti-melanoma MoAb was labeled with indium-111 and indium-114m and administered to BALB/c mice. The mice receiving 111In MoAb were sacrificed at 4 and 72 h, while those receiving 114mIn 96.5 MoAb (50-day physical half-life) were sacrificed at 4 h and 3, 15, and 30 days. Multiple tissues were counted against a standard of the injectate and the data expressed as percent injected dose per organ and percent total dose excreted in the urine and feces. The 111In- and 114mIn-labeled MoAbs had nearly identical distribution through 72 h. Over the 30-day period 25% of the 114mIn label was excreted in the urine and 50% eliminated in the feces. All of the tissues studied showed a decrease in 114mIn in the 30-day period. We conclude that the metabolic products of indium-labeled MoAbs, the indium itself, or a combination of both are eliminated from the tissues over a period of several weeks and do not accumulate to a significant extent in any single site.
Halpern
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SE
Veterans Administration Hospital, San Diego, California, USA.
Bartholomew
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D000818:Animals; D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics*; D000951:Antigens, Neoplasm / Q000276:immunology; D018796:Immunoconjugates / Q000493:pharmacokinetics*; D007074:Immunoglobulin G; D007205:Indium Radioisotopes / Q000493:pharmacokinetics*; D058950:Melanoma-Specific Antigens; D051379:Mice; D008807:Mice, Inbred BALB C; D009363:Neoplasm Proteins / Q000276:immunology; D013997:Time Factors; D014018:Tissue Distribution
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D018796:Immunoconjugates; D007074:Immunoglobulin G; D007205:Indium Radioisotopes; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins