Biodistribution, cellular localization, and in vivo tolerability of 35S-labeled antiinflammatory dendritic polyglycerol sulfate amine

Antiinflammatory dendritic polyglycerol sulfate (dPGS) holds great potential in the treatment and imaging of inflammatory processes. Here, we studied its biokinetic behavior, biodistribution, target cells, and in vivo toxicology. Following intravenous or subcutaneous application of 35sulfur-labeled dPGS amine with a molecular weight of 10.05 kDa and a hydrodynamic diameter of 5.7 ± 1.5 nm to mice, tissues were collected at specific time points (2, 15 min; 1, 24 h; 5, 21 days) and analyzed by liquid scintillation counting, autoradiography, radioluminography, and light microscopic autoradiography. The blood half-life of dPGS amine was 12 days. The major route of elimination was via the bile and feces. Elimination via the kidney and urine was only initially observed after i.v., but not after s.c. injection. Regardless of the administration mode, liver and spleen were late target organs where dPGS amine accumulated in phagocytic cells. Despite bioaccumulation, toxicological histopathology failed to identify any adverse effects at any time and in any tissues examined suggesting a high in vivo biocompatibility and encouraging future investigation for biomedical applications.