Stability of Ala 125 recombinant human interleukin-2 in solution

Herein, we describe the preformulation study of Ala 125- recombinant human interleukin-2 (rhIL-2A(125)) in solution. This modified form of the natural human IL-2 is obtained by the replacement of cysteine with alanine at position 125. The compatibility of this rhIL-2A(125) with type I borosilicate glass vials showed no significant adsorption at liquid-vial interface. The effect of single excipients on the stability of this lymphokine was evaluated through RP-HPLC, SDS-PAGE and biological activity assay. Polysorbate 80 at high concentrations decreased the stability of rhIL-2A(125) in solution. On the other hand, the use of antioxidants (methionine and EDTA Na(2)) diminished the oxidation rate of the active ingredient. Additionally, a group of amino acids (glutamine, alanine, glycine and histidine) stabilized rhIL-2A(125) in different grades, and glycine at 5 mg mL(-1) allowed for the best stability behaviour. Taken together, these preformulation results can be used to design an adequate liquid vehicle for rhIL-2A(125) to be manufactured for human use.