Source: Link Testing Instruments Co.,Ltd.
For most drugs, moisture-proofing during storage and shelf life is one of the key measures to prevent drugs from becoming ineffective or even producing toxic and harmful substances. Testing the water vapor permeability of packaging is an important part of moisture-proofing of drugs. Common pharmaceutical packaging materials include plastic composite films, aluminum-plated composite films, blister packaging, ampoules, plastic tubes, vials, etc., and their moisture barrier properties are not the same. Different drugs also have different requirements for the moisture barrier properties of packaging materials. For example, granules, effervescent tablets, capsules, powder injections and other types of drugs have higher requirements for the water vapor permeability of packaging materials, while liquid drugs, such as injections and eye drops, have lower requirements for the water vapor permeability of packaging materials. Therefore, by testing the water vapor permeability of packaging materials, choosing packaging suitable for drugs is a basic requirement to ensure that the quality of drugs is good and they will not absorb moisture and deteriorate during the shelf life.
Test methods and test instruments
The pharmaceutical packaging standard related to the water vapor permeability test of pharmaceutical packaging is YBB00092003-2015 "Water Vapor Permeability Determination Method". This standard stipulates four water vapor permeability test methods, namely cup method, electrolytic analysis method, weight method, and infrared detector method. The infrared detector method is an arbitration method. This article tests the samples based on the infrared detector method.
This test uses the LTWTC-303H water vapor transmission rate test system developed and produced by Link Testing as the test equipment to test the water vapor transmission rate of the samples.
Test principle: The infrared detector method uses the principle that infrared light can quantitatively absorb water molecules. The water vapor permeability of the sample is obtained by testing the attenuation of infrared light after passing through a carrier gas containing water vapor. The specific implementation process is that after the sample is clamped in the test chamber of the equipment, the test chamber is divided into two test chambers, the upper chamber and the lower chamber. During the test, the upper chamber is filled with high-purity nitrogen with a certain humidity, and the lower chamber is filled with low-humidity nitrogen. Under the action of concentration difference, water vapor penetrates the sample from the upper chamber into the lower chamber, and carries the nitrogen to the infrared detector for analysis, thereby obtaining the water vapor permeability of the sample.
Test sample and test process
Test sample: This test uses a certain aluminum-plated composite film material for pharmaceutical packaging as the test sample.
Test process:
(1) Use a special sampler to cut 3 samples from the surface of the sample and adjust the state for 4 hours in an environment of 23±2℃ and 50±10%.
(2) Apply a layer of vacuum grease around the test cavity of the equipment, clamp the sample on the surface of the test cavity, and clamp it with a sample clamp.
(3) Set the test temperature (38℃), test humidity (90%), sample name and other parameter information, click the test option, and the test starts.
(4) Turn on the gas source and adjust the carrier gas flow rate to make the humidity in the test cavity reach the set value. After the test, the equipment automatically calculates the water vapor permeability of the sample based on the test value.
Test results and analysis
The water vapor transmission rates of the three samples tested this time were 0.73 g/(m2·24h), 0.77g/(m2·24h), and 0.71 g/(m2·24h), respectively. The water vapor transmission rate of the sample was the average of the test results of the three samples, which was 0.74g/(m2·24h).
The water vapor permeability of pharmaceutical packaging is an important factor affecting whether the packaged drugs are prone to moisture absorption and deterioration during storage. This paper introduces the method of using infrared detectors to test the water vapor permeability of soft plastic packaging materials by testing the water vapor permeability of aluminum composite films used for pharmaceutical packaging. The entire test process has little interference from human factors, the equipment is highly intelligent, the operation is simple, the test results are repeatable, and the water vapor permeability of the samples is relatively uniform.
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