Polyethylene glycol–polyvinyl alcohol grafted copolymer: Study of the bioavailability after oral administration to rats

The absorption, urinary excretion, and the biliary excretion of a single oral dose of 10 or 1000 mg/kg bw of 14C-polyethylene glycol–polyvinyl alcohol (PEG–PVA) grafted copolymer were studied in adult male and female rats. In a balance/excretion experiment, the total excretion of ingested radioactivity was determined over a period of 168 h and residual radioactivity was detected in selected tissues and the carcass. In a biliary excretion experiment, excretion of radioactivity via the bile duct was determined over a period of 48 h after administration of the substance to cannulated rats. Most, if not all, of the radioactivity (>100%) was excreted within 48 h via the feces regardless of sex or dose. Urinary excretion was very limited: 0.45–0.50% of dose at the low dose and 0.22–0.27% of dose at the high dose. At both dose levels, residual radioactivity in the carcass and all organs and tissues after 168 h was ⩽0.02% of dose. Biliary excretion was 0.01–0.02% of dose. Based on these findings, the bioavailability of PEG–PVA grafted copolymer was determined to be <1% demonstrating that absorption was virtually negligible following a single oral administration to male and female rats.