Pharmacokinetic comparison of leukocyte and Escherichia coli-derived human interferon type alpha

Abstract

Human alpha interferons derived from leukocytes (HuIFN-α-Le) and from an Escherichia coli clone (HuIFN- α 1) were compared for their relative abilities to distribute systemically in mice following intramuscular or intraperitoneal injections, and for their rate of clearance from the blood. HuIFN- α 1, which is about 30–50 times more active on bovine cells than on human cells, was as efficient as HuIFN-α-Le at entering the bloodstream following injections by either route. However, HuIFN-α-Le was still present in the circulation at about 30% of peak serum IFN levels at 8 h post-inoculation and was present at about 3–5% at 24 h, whereas HuIFN- α 1 was present at only about 3% of peak IFN serum levels at 8 h and was undetectable (< 1%) at 24 h. These data indicate the importance of evaluating the pharmacokinetic properties of each of the molecular forms of interferons obtained from genetically engineered organisms, as each molecular species of interferon may have importantly distinct pharmacologic properties.