Review on oxygen resistance detection technology o

Summary of oxygen resistance detection technology of high barrier drug packaging materials

the most basic requirement of consumers for medical packaging is absolute safety! High barrier materials are widely used in pharmaceutical packaging because they have excellent oxygen resistance, moisture resistance and sealing, can prevent dust, dirt, moisture and static electricity, and can effectively avoid the destruction of internal components by gas, light and other media. Therefore, they can prolong the shelf life

for high barrier drug packaging materials, how to judge its permeability resistance (that is, how its barrier ability to oxygen is, oxygen is the most important factor affecting the decay of substances due to its unique active chemical properties), professional testing and judgment need to be carried out with professional testing instruments

therefore, the detection of oxygen resistance of packaging materials is a core test item of pharmaceutical packaging

due to the difficulty of the detection technology, the precision of the precision test is required to be high, and the test range should be wide. It is necessary to simulate the natural storage environment of the packaging and check the results. Next, we will focus on the oxygen barrier detection technology of drug packaging materials

1 oxygen resistance detection of high barrier medical packaging materials -- comparison between differential pressure method and electric quantity analysis sensor method

at present, the test and research of oxygen permeability in the industry can be divided into differential pressure method and electric quantity analysis sensor method from the perspective of test principle

however, in the actual test process, due to the pressure difference between the two sides of the material, it will destroy the structure of some relatively fragile materials and produce small cracks, pinholes and other defects; It will also make the material deform, thin and increase the air permeability area, which will affect the experimental results

and most of the internal and external pressures of the packaging container are the same, which cannot simulate the actual use. A large number of facts have proved that the detection result of differential pressure method is larger than that of electric quantity analysis method, especially at low transmittance. At the same time, there is evidence that the magnitude of the pressure difference will significantly affect the test results when the oxygen transmittance is measured by the pressure difference method

the electricity analysis sensor should be able to control gases with different humidity, temperature and oxygen content, and can more effectively simulate the actual use conditions of the package. The pressure on both sides of the sample is the same during the test, which is conducive to reducing the leakage and damage to the sample during the test. The electricity analysis oxygen transmittance tester can accurately determine the composition of oxygen in the transmitted gas, so the test result is more accurate and reliable

in addition, standard proofreading can also be used (see Table 1)

through the above comparison, it is believed that we should choose the electric quantity analysis sensor method. This method has high testing accuracy and wide testing range (oxygen: 0.008, -432000cc/m2/d9y/0.0005-28000cc/looin2/day; water vapor: 002-1000g/m2/Dav/0.0002-64.5g/looin2/day). It can also simulate various natural environments where packaging materials are stored for testing, and can carry out result calibration, and the testing time is relatively short

2 oxygen resistance detection steps of electric quantity analysis sensor method (see slide explanation)

3 safe packaging of medical drugs

how to ensure the absolute safety of pharmaceutical packaging? In addition to requiring us to strictly control the production process and organize production in strict accordance with various process conditions, we should also carefully select packaging materials, and require packaging material suppliers to provide professional testing reports. In addition to the general items involved in health indicators, tensile properties, heat sealing properties, friction properties, transparency and so on, we should also do professional testing research especially for oxygen permeability and oxygen humidity. Moreover, we suggest that drug enterprises should personally test the materials in a simulated harsh environment and under various conditions, and make full preparations for the testing before doing good, so as to prevent the trouble before it happens, so as to effectively ensure the safety of drug packaging

４. Introduction to test methods

4 1 test method for gas transmission rate of vacuum aluminum products

nowadays, barrier packaging materials are widely used in food, medicine and other fields. In barrier packaging, aluminum foil conforming materials and vacuum aluminum crossing materials are often used. The replacement of aluminum foil with vacuum aluminum ferry material not only reduces the production cost, but also reduces the consumption of aluminum. Therefore, this low-cost and environmental friendly material has been unanimously recognized by manufacturers and users

vacuum aluminized materials can be divided into two categories: vacuum aluminized paper and vacuum aluminized film. Vacuum aluminized films mainly include: VMPET polyester aluminized film, VMCPP cast polypropylene aluminized film, vmbopp biaxially stretched polypropylene aluminized film, vmcpe polyethylene aluminized film and vmpvc PVC aluminized film. These materials are formed by aluminizing the surface of polymer film as the substrate. The common characteristics of vacuum aluminized materials are: the aluminized layer has poor wear resistance, so it is easy to produce scratches, and the dense surface is damaged

as a barrier material, vacuum aluminized paper and film have a fertilizer implementation area of more than 35 million mu. Their barrier performance is usually evaluated by two indicators: oxygen transmission rate and water vapor transmission rate. Two different test methods can be used for experiments

4.2 test method of water vapor transmission: cup method and Mooon moisture permeability tester

according to GB/T 1037-1988 standard, the water vapor transmission of vacuum aluminized film is tested by using the weighing principle of cup method. In the process of preparing the sample, cup sealing is an important step. In this step, the part of the sample in contact with the metal seal ring will inevitably be subject to certain friction and scratches. At the same time, high-temperature liquid wax will also affect the barrier layer, and the water vapor transmission of the sample will be affected to a certain extent. In addition, the direction of water vapor transmission should be considered during the experiment. Because the vacuum aluminizing layer is always exposed on one side of the vacuum aluminizing film, when water vapor passes through the aluminizing layer towards the substrate layer, the aluminizing layer is exposed in a high humidity environment, and the aluminizing layer formed by adsorption will produce pinholes, thereby increasing the transmission of water vapor and affecting the use value of materials

according to ASTM F 1-249-200l standard, MOCON moisture permeability tester is used for water vapor transmission test. The sample is clamped and fixed by the upper and lower cavities, and the fixing device will not produce too much friction on the sample. The lower chamber of the experimental chamber is filled with distilled water or salt solution, forming various humidity environments, so this method also needs to pay attention to the direction of water vapor transmission

summarize according to the experiment: when testing the water vapor transmission rate of the vacuum aluminized composite film with the aluminized layer exposed on the surface, the aluminized layer should face the side of the low humidity environment as far as possible, especially in the environment with 100% relative humidity, so as to reduce the impact of water vapor on the compactness of the aluminized layer; In terms of experimental methods, according to ASTM f1249-2001 standard, MOCON moisture permeability tester can better avoid the influence of experimental operation on experimental data and obtain the test results of the sample in its original state

4.3 detection method of oxygen transmission rate: differential pressure method, isobaric method

according to GB/T 1038-2000 standard, the principle of differential pressure method is used to test the oxygen transmission rate of vacuum aluminized film or paper. The experimental steps are as follows: seal and fix the sample, vacuumize a pair of experimental chambers, fill the upper chamber with oxygen, continue vacuumizing a pair of lower chambers, stop vacuumizing and start the test. The wear resistance of vacuum aluminized materials is poor, and when this method is used to fix the sample, the upper and lower cavities of the experimental cavity are locked by the pressure applied by the fixture, and the sealing ring will produce great friction on the sample, so that the wear resistance of the material becomes poor. In addition, the aluminized layer of vacuum aluminized film, another 14.2% of the bridges are too old-fashioned in function, and usually rely on electrostatic adsorption on the substrate. When the aluminized layer faces the lower cavity during the experiment, the aluminized layer will be affected to a certain extent during the vacuum pumping step, reducing the oxygen resistance performance. The vacuum aluminized paper is hard and brittle, which is relatively rigid compared with the film material. There are some defects in the experiment of differential pressure method, such as poor sealing, and easy to damage the aluminized layer when sealing and fixing

therefore, when testing the oxygen transmission rate of vacuum aluminized materials, it is recommended to use the isobaric method. MOCON oxygen permeability tester is used according to ASTM D 3985-2002 standard. On the one hand, in the steps of sealing and fixing the sample, MOCON oxygen permeability tester has good sealing measures, and the fixing device can avoid repeated friction; On the other hand, there is no vacuum pumping step in this method, so there is no need to worry about the quality of the aluminum coating being affected, and the oxygen transmittance can be measured from both sides of the material

source: China gas separation equipment business