Influence of packaging material on the liquid stability of interferon-alpha2b.

PURPOSE

In this article we studied the effect of the packaging material on the liquid stability of interferon alpha 2b (rhIFN-alpha2b).

METHODS

The compatibility of this cytokine with type I borosilicate glass ampoules was evaluated by ELISA and RP-HPLC, at 4 degrees C and after heat sealing. Additionally, the influence of protein concentration (3 and 10 MIU/ml), buffer species (sodium phosphate, sodium citrate and sodium citrate-phosphate) and additives (polysorbate 80 and EDTA Na(2) x 2H(2)O) were studied in samples with and without contact with chlorobutyl stoppers by RP-HPLC.

RESULTS

The compatibility of this cytokine in sodium phosphate buffer, with type I borosilicate glass ampoules showed a significant adsorption at the lowest concentration. This influence was eliminated with a polysorbate 80/benzyl alcohol-based vehicle. The effect of the heat sealing of ampoules on the stability of rhIFN-alpha2b showed two degradation peaks when a volume of 1 ml was dispensed. However, with a lower (0.5 ml) volume, the degradation was not detected. On the other hand, samples in contact with chlorobutyl stoppers increased the apparent degradation rate constant in the range of 6.74 +/- 0.38 to 46.34 +/- 3.11 x 10(3) day-(1). This effect significantly decreased in about 1.2- and 1.1-fold when sodium citrate or sodium citrate-phosphate buffers, respectively, were evaluated. Results from the evaluation of EDTA Na(2) x 2H(2)O or polysorbate 80 showed a similar behavior. These additives reduced the apparent degradation rate constant in the range of 2.01 +/- 0.14 to 25.51 +/- 3.57 x 10(3) day-(1).

CONCLUSIONS

The adsorption of the cytokine to type I borosilicate glass ampoules was eliminated with a polysorbate 80/benzyl alcohol-based vehicle, and the deleterious effect of the heat sealing decreased with a lower (0.5 ml) volume. Experimental data indicated that the contact with chlorobutyl stoppers accelerates the degradation of rhIFN-alpha2b. However, protein concentration, buffer species and pharmaceutical excipients can modulate this effect.