TABLE 1

Summary of PEG metabolism and excretion data (for more, detail see text)

PEG mol. wt.
Clearance Route
Urinary
Hepatic
Metabolism
<1000 PEG1000: 86% excreted in the urine in humansa PEG400: not eliminated in the bile in dogsa PEG400: up to 25% metabolized in humansa
In rat, urinary recovery of PEG1000 essentially completej PEG900: Evidence that PEG is excreted in the bile in ratsb PEG900: 24% of biliary excreted material are PEG metabolites in catb
Urinary clearance predominates (>90% of the total clearance) in mousef PEG900: concentrations in human bile 31 times higher than those in plasma; similar findings in pigs and catsg PEG1000: up to 15% metabolized in humansa
Hepatic clearance a minor (<10%) route in mousef
>1000 PEG4000: 61% of the dose eliminated in the urine of ratsh PEG4000: 20% of the dose eliminated in the feces of ratsh PEG6000: up to 4% metabolized in humansa
PEG6000: 96% excreted in urine in humansa Hepatic clearance a minor (<10%) route in mousef
Urinary clearance predominates (>90% of the total clearance) in mousef
>6000 Urinary clearance predominates (>90% of the total clearance) in mousef Hepatic clearance a minor (<10%) route in mousef
Comments and Conclusion In dog PEG400-4000 cleared at a rate equivalent to GFRi Conclusion: PEG900 has the highest biliary clearance in the cat (PEGs investigated = 450, 900, 2500 and 4000)c Acid and hydroxyl acid metabolites seen in plasma and urine of animals and humansc
Conclusion: Urinary clearance predominates for PEGs up to 190,000 molecular weight. High molecular weight PEGs can be excreted into the urine. The bile represents a minor route of PEG clearance of unchanged PEG Sulfation observed in animalsd
Alcohol dehydrogenase and P450 have been reported to be responsible for the metabolism of PEGe
Metabolism represents a minor route of elimination for PEG