How to solve the problem of air residue in prefilled syringes

Update:28 Mar 2020

Pre-filled syringes have become very popular in the Wes […]

Pre-filled syringes have become very popular in the West, but they are still a new type of packaging in China. Pre-filled syringes have very good stability, so the market potential is huge and won the favor of customers.

It is not possible to produce pre-filled syringes without air bubbles, and some air molecules will remain in the syringe even at the lowest vacuum. If the best process conditions are used, the bubbles may be so small that they are not visible to the naked eye. The size of the remaining air bubbles mainly depends on the vacuum and filling level in the syringe during operation. The amount of dissolved gas is negligible. For example, the traditional vacuum plugging method is used: filling a 0.75ml water-based product in a 1ml (long) syringe and pressing the plug at a pressure of 100mbar. 2mm bubbles (based on 1000mbar pressure).

Because the gas is dissolved in the product, the volume of the bubbles can be reduced by about 10%. Generally, the pressure in the syringe must be significantly higher than the vapor pressure of the product. Low vacuum, small friction, high filling level, high gas solubility, and the use of a push rod all reduce the residual gas space in the syringe.

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