Pharmacokinetic Parameters of Oral Pegylated IFN-λ1

We studied the pharmacokinetics of a pegylated IFN-λ1 (PEG IFN-λ1) after its oral administration to rats in different therapeutic doses. The hypothesis on linear pharmacokinetics of PEG IFN-λ1 within the dose range of 2.6-7.8 μg/kg was confirmed, high for protein molecules bioavailability from 17.5 to 21%, the absence of intravascular deposition, and effective elimination with feces and urine (85 and 15% of the administered dose, respectively) were demonstrated. At the same time, the mean retention time for PEG IFN-λ1 in the circulation is 6.46-6.65 h and half-life is 3 h. These findings give ground for continuing experimental studies of PEG IFN-λ1 pharmacokinetics, in particular, tissue distribution of the drug.