The effects of withdrawal and duration of storage on the sterility of multiple dose vials.

The effects of the number of withdrawals and the duration of storage after withdrawals on the sterility of multiple dose vials were studied. Separate vials containing sterile fluid thioglycolate medium and soybean-casein digest were subjected to 1 or 5 withdrawals either inside a laminar flow hood or outside of it but in a clean room. Immediately after the completion of withdrawals, the vials were stored at 5° C for 5,10, or 15 days, and then incubated. The sterility of each vial was determined by visual inspection for turbidity of the vial contents and by subculturing the vial contents on human blood-agar plates. The results of this study indicate that the sterility of the multiple dose vials can be maintained for at least 15 days after being subjected to 5 withdrawals, provided the withdrawals are performed with aseptic technique.