To determine the pharmacokinetic properties of advanced oxidation protein products (AOPP), we prepared oxidized human serum albumin (oxi-HSA) using chloramine-T (a hypochlorite analogue) in vitro. The AOPP and dityrosine content of oxi-HSA (AOPP content, 244.3+/-12.3 microM; dityrosine content, 0.7+/-0.11 nmol of dityrosine/mg protein) were similar to those of uremic patients. In structural analysis, the increases in AOPP and dityrosine content of HSA induced slight decreases in its alpha-helical content. In pharmacokinetic analysis, oxi-HSA left the circulation rapidly, and organ distribution of oxi-HSA 30 min after intravenous injection was 51% for the liver, 23% for the spleen, and 9% for the kidney, suggesting that the liver and spleen were the main routes of plasma clearance of oxi-HSA. The liver and spleen uptake clearance of oxi-HSA were significantly greater than those of normal HSA (CLliver, 5058+/-341.6 vs 24+/-4.2 microL/hr [p<0.01]; CLspleen, 2118+/-322.1 vs 32+/-2.7 microL/hr [p<0.01]). However, uptake by other organs was not significantly affected by oxidation. These results suggest that the liver and spleen play important roles in elimination of AOPP.