Preparation of homogeneous human fibroblast interferon

A process for producing human fibroblast interferon as a homogeneous protein which process comprises the following steps in combination:

• A. passing an aqueous solution of human fibroblast interferon in an impure state through an affinity chromatography column so as to absorb said interferon onto said column and thereafter eluting said interferon from said column and obtaining said interferon in selected fractions of said eluate in a state of enhanced purity;
• and
• B. passing the selected said interferon fractions obtained in Step A through one or more buffer equilibrated hydrocarbon bonded silica matrix column under high pressure liquid chromatography conditions wherein said hydrocarbon is selected from the group consisting of cyclohexyl, phenyl, diphenyl, octyl, octadecyl and cyanopropyl, to absorb said interferon onto said column and thereafter eluting said interferon from said column with a gradient of an acidic aqueous buffered mixture of water miscible solvents and obtaining interferon as a single distinct peak in selected fractions of said eluate in the state of a homogeneous protein.