This research protocol "Comparative pharmacokinetics and pharmacodynamics of peginterferon Bacterial Intravenous Protein 48 kilodaltons (BIP48) and 40 kilodaltons (40kDa) in healthy volunteers." This is a Phase I clinical trial which will compare pharmacokinetic and pharmacodynamic parameters, and safety of two products: peginterferon alfa-2a (PEGASYS ®) and BIP48. It will be a double-blind, randomized crossover with a rest period (wash-out) of 4 weeks. The study population will be 32 healthy male volunteers to whom will be administered a single dose of 180 microgram of each product, subcutaneously. The study will have a total duration of 14 days in each treatment step. The serum concentration of PEG-interferon for both products, measured by enzyme immunoassay (EIA) and by antiviral activity of PEG-interferon, is the main variable.For this purpose 15 samples of each volunteers will be needed. Clinical and laboratory variables, useful as pharmacodynamics parameters Beta-2 microglobulin (β2M) - 2'5'oligoadenylate synthetase - oligoadenylate synthetase (OAS)- and neopterin) and safety evaluation, will be measured.