Due to the fact that some proteins have a tendency to bind to glass surfaces, plastic CZ-resin vials were evaluated as an alternative material to glass vials for packaging protein-based parenteral formulations. Physico-chemical tests including protein binding, extractable evaluation, oxygen permeation, light transmission and moisture loss were performed. Data show that two proteins (A and B) were found to bind to USP type I glass but not to CZ-resin. The CZ-resin vials passed all USP test specifications for extractables (organic extractable, non-volatile residue and residue on ignition). The oxygen permeation rate (79.06 cm(3)mm/m(2)24 h atm) was consistent with that reported by the vendor (67 cm(3)mm/m(2)24 h atm). The value obtained for light transmission, which was also found to be consistent with that reported by the vendor, shows that these vials offer no protection from light. The average moisture loss from 2 cm(3) vials filled with water was gravimetrically determined to be 0.04 mg/day/vial when the vials were stored at 40 degrees C/75% relative humidity (RH). Assuming a 1cm(3) product fill, this corresponds to approximately a 3% loss over a 2-year period. However, moisture loss was found to be negligible at the typical storage condition of 5 degrees C for protein formulations. The physico-chemical tests indicate that CZ-resin vial is a suitable candidate for packaging parenteral formulations since it shows low moisture loss at typical storage condition of 5 degrees C, and does not leach out extractables. However, it should not be used for light-sensitive and oxygen-sensitive parenteral formulations. For proteins A and B, the CZ-resin vial is a viable alternate to the use of glass vials since it offered significantly less protein binding. Protein binding in general, should be evaluated on a case by case basis, since it may vary for different proteins and under different formulation conditions.