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Source： Link Testing Instruments co.,ltd

Medical packaging comes in various forms, such as bags, bottles, tubes, gas-filled packages, aseptic packages, strip packages and child-resistant packages, etc., even so, most of them are made of flexible materials and contain a certain amount of gases inside. For instance, gas-filled packages are usually used for liquid and powder-formed drugs and medicines to guarantee the efficacy. In sterilization or transportation process, the gases will be internally pressurized the package and its sealed edges because of heat or compression. If the package doesn’t have sufficient internal pressurization resistance, it may be deformed or even broken. Therefore, it is necessary to monitor the internal pressurization resistance of the medical packaging to reduce the breakage ratio.

Figure 1. Common Forms of Medical Packaging

Test method mentioned in this article is based on ASTM F1140: Standard Test Methods of Internal Pressurization Failure Resistance of Unrestrained Packages and ISO 11607 Packaging for Terminally Sterilized Medical Devices

Specimens 

Infusion bags provided by one manufacturer of medical apparatus

Testing Instrument

Link Testing LTMFY-06S Leak and Seal Strength Detector

Figure 2. LTMFY-06S Leak and Seal Strength Detector

Summary of Test Methods

1. Test Method A (Burst Test) -- Packages are tested in an apparatus that Internally pressurizes the package until the package fails. The pneumatic supply and pressurization equipment need the capability to maintain an increasing pressure until the package bursts. The test measure is the maximum pressure detected before the package fails.

• Test Method B (Creep Test) – Packages are tested in apparatus that internally pressurized the package to specified pressure and maintains that international package pressure for a specific time. The measure is pass/fail.

• Test Method C (Creep to Failure Test) – Package are creep-tested and held until the package fails. Test setup is similar to that of Creep Test except the pressure setting will need to higher to ensure the package fails in a reasonable amount of time. The test measure is the time until failure.

Test Procedures

Condition the samples at 23℃, 50%RH for at least 48 hours.

1. Burst Test

(1) Paste a sealing gasket on the center of the sample surface. Insert the probe into the sample through the sealing gasket. Make sure the other parts of the sample not damaged by the probe.

(2) Select burst test mode. Press Test button to start the test. Then the sample will be inflated by injection of gas until the sample ruptures. Record the pressure value and mark the position where the sample ruptures.

2. Creep Test

Insert the probe into the sample with procedures in 1.(1). Select creep test mode and set test pressure and pressure maintaining time and other parameters. Press Test button. Then the sample will be injected with gas until specified pressure is achieved. Then the system will start timing. When timing is finished, observe whether the sample ruptures and record the position where it ruptures.

3. Creep to Failure Test

Insert the probe into the sample with procedures in 1.(1). Select creep-to-failure test mode and set test pressure. Press Test button. The sample will be inflated by injection of gas with specified pressure. The system will start timing. Record the time used from start to the rupture occurs.

Test Results

1. Burst Test – The burst pressure is 80.4kPa and failure occurred at the lower sealing edge.
2. Creep Test – The Internal Pressure is held at 65kPa and hold time is 30 seconds. The package is still unbroken.
3. Creep to Failure Test – The Internal Pressure is held at 75kPa. Package hold 12 seconds until failed

Conclusion

The medical packaging should have sufficient internal pressurization resistance; otherwise, the packaging may be liable to be broken during sterilization and transportation process. The heat seal of sealing edges and flexibility are the factors that may influence the internal pressurization resistance of medical packaging. Link Testing LTMFY-06S Leak and Seal Strength Detector is an intelligent and multiple functioned equipment. It can be used for Bubble Emission Leak Test (ASTM F2096) as well as the tests mentioned in this article based on standards ASTM F1140, ASTM 2054. Test pressure of this equipment can be widely customized from 600kPa to 1.6MPa (87psi ~232psi). It is also equipped with professional software for uniform and systematic management of test results and test reports.

For more details please visit www.linktesting.org