Disposition of Radiolabeled FAVOR PAC in Rats

FAVOR is the name for a family of superabsorbent cross-linked sodium polyacrylate polymers developed by Stockhausen GmbH & Co KG (Krefeld, Germany) that are known for their ability to absorb and retain large volumes of fluid. The absorption, distribution, rates and routes of excretion of radiolabeled FAVOR PAC (CAS Registry No. 9003-04-7; [14C]FAVOR PAC), one member of the FAVOR family, were evaluated following a single oral administration of the compound. Male Sprague–Dawley rats were administered single doses of 26 to 39 mg/kg [14C]FAVOR PAC by gavage. Approximately 98.8% (normalized mean) of the total administered dose was excreted in the feces within 5 days, and the majority (∼88%) was excreted within the first 24 h. Urinary excretion accounted for 0.69% (normalized mean) of the total administered dose. Recovery of radioactivity in the organs, tissues, and carcass was generally less than 0.5% of the dose administered. Levels of total radioactivity in whole blood ranged from 0.75 to 1.20 μg equiv/g. Biliary elimination of total radioactivity accounted for less than 0.1% of the dose administered. The results indicate that FAVOR PAC is poorly absorbed and rapidly eliminated in feces following oral administration.