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Seal Performance Test Method of Plastic Vial for Eye Drops Packaging

Apr 15,2020

Source: Link Testing Instruments Co., Ltd

With the popularization of computer, mobile phone and other electronic products, there are more and more patients with eye disease due to the excessive use of eyes. In recent years, eye health care has become one major subject in people’s daily life. In this context mentioned above, ophthalmic products have been developed rapidly. The eye drop is the most common ophthalmic product, which can be used to relieve the eye fatigue, as well as prevention and treatment of eye diseases.

Usually the eye drop is packed in plastic vial, which is easy to squeeze in use. Seal performance is the main property that shall be considered when selecting plastic vials for eye drop. On one hand, if the seal performance of the plastic vial is insufficient, the eye drop may leak. On the other hand, the eye drop may be oxidized and become ineffective or even do harm to the eyes in contact with too much air, especially when the seal performance of the plastic vial is poor. Therefore, it is critical to have the plastic vial with good seal performance to ensure the quality of the eye drop within its shelf life.

This article provides a simplified seal performance test method of plastic vial for eye drop for your reference. The test specimens are PP vials for eye drop and the testing instrument is Link Testing’s LTY-01 Leak Tester. During the tests, the specimen is submerged in fluid contained in the vessel within the vacuum chamber. Then the vacuum chamber is evacuated to form differential pressure between the inside and outside of specimen. The leakage property could be obtained by observing the steady progression of bubbles from the specimen and how the specimen expands and restores to its original shape after vacuum release.

Figure 1. Plastic Vials for Eye Drops

The tests can be performed according to the following detailed procedures.

  • Screw the caps of the 3 specimens tight with Link Testing’s LTTT-20 Torque Tester. The torque should be 40 N·cm.
  • Submerge one of the specimens with cap into the water within the vacuum chamber. Apply a layer of water on the sealing ring and set the cover on the vacuum chamber.
  • Set vacuum degree -20 KPa and pressure maintaining time 2 min. Press Test button to start the test.
  • Observe the specimen and press Stop button when there is a steady progression of air bubbles from the specimen surface. Stop evacuation of the vacuum chamber. Record the time when the air bubbles come out and the leak position.
  • Hold the vacuum for a specified time period (pressure maintaining time). Release the vacuum, remove the lid, and examine the specimen for the presence of test fluid inside the specimen.
  • Test other 2 specimens in the same way as mentioned in step 2 to 5.

If there are no air bubbles coming out during the evacuation and no test fluid is found inside the specimen after test, it proves that this specimen has sufficient seal performance.

Leak Tester LTY-01
Torque Tester LTTT-20

For more details about Link Testing’s LTY-01 Leak Tester and LTTT-20 Torque Tester, please visit

About Link Testing Instruments Co., Ltd:

Link Testing Instruments Co., Ltd is one leading supplier of packaging testing instruments, which is headquartered in Jinan.

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