Requirements and methods for barrier testing of in

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Requirements and methods for barrier testing of infusion bags

Abstract: both differential pressure method and isobaric method are required in the barrier testing of infusion bags, but the two kinds of equipment need to be invested twice, which increases the burden on enterprises and institutions. For this reason, Languang has launched perme-dm2/330 double detection gas transmittance tester integrating two test methods, which provides a better choice for the detection equipment configuration of drug bag system and infusion bag manufacturers

key words: infusion bag, infusion film, oxygen permeability, nitrogen permeability, soft plastic

infusion packaging containers mainly include glass bottle, soft plastic infusion bottle (PP or PE), soft plastic infusion bag (PVC and non PVC). The original infusion packaging was a glass bottle. Although it had been improved several times, it could not get rid of the common defects of glass, such as fragile, poor sealing of bottle mouth, easy chip falling from puncture, and increased secondary air pollution during use. Therefore, plastic containers (plastic bottles and PVC infusion bags) appeared in the 1960s, and non PVC composite membrane infusion bags were developed in the early 1990s. Nowadays, in developed countries in Europe and America, soft plastic infusion containers account for about 96% of the total market. Although the competition between soft plastic infusion bottles and soft plastic infusion bags is fierce, the soft plasticization of injection packaging is the general trend. Although glass infusion bottles still occupy a large market in China, the future development direction is also soft plastic infusion packaging

1. Infusion bags must be tested for material barrier

compared with traditional glass packaging, the new soft plastic infusion packaging has significant advantages in environmental protection, cost, health, safety and convenience of use, but it shows deficiencies in barrier, sealing performance and transparency, of which barrier has the most prominent impact. Oxygen is the main factor that leads to the deterioration of the injection. If the oxygen barrier of the infusion packaging container is not qualified, the drug will fail and deteriorate in advance, and the consequences will be unimaginable. Therefore, in order to reduce the oxygen entering the package and delay and prevent the oxidative deterioration of drugs in the injection, antioxidant, metal chelating agent or inert gas are often used in the infusion packaging. Nitrogen is stable in nature. It is often used as an inert gas together with carbon dioxide (a small amount) to replace the air in the package. If the nitrogen barrier of the infusion packaging container is not high, the high concentration of nitrogen in the package will leak out of the package, which will not only weaken the protective effect of the inert gas on the injection, but also increase the oxygen content in the package and shorten the shelf life of the product. The penetration of water vapor will affect the concentration of drugs, especially for solution type injections, which will increase the difficulty of dispensing for medical personnel, and also bring hidden dangers to drug safety. As we all know, the barrier property of glass is excellent. It can be considered that various gases and water vapor cannot penetrate through the glass. However, the barrier property of flexible plastic packaging materials is not so excellent. Therefore, the barrier property of flexible plastic infusion packaging must be tested

2. Requirements for barrier testing in the standard for medicine bags

due to the excellent barrier property of glass, there is no requirement for barrier testing in the standards for glass infusion containers such as YBB sodium calcium glass infusion bottle and YBB neutral borosilicate glass infusion bottle, and the tightness between the rubber plug and the container is the focus of testing (in the rubber plug standard). However, once the material becomes soft plastic, the detection of barrier becomes very necessary. For example, since the first edition of the standard for soft plastic infusion bottles (YBB "low density polyethylene infusion bottles" and YBB "polypropylene infusion bottles") was able to meet the measurement requirements of the tested objects in 2002, the test methods and indicators for the water vapor permeability of infusion bottles have been described, and the test requirements for the water vapor permeability of packaging containers have also been listed in other standards for oral liquid pharmaceutical soft plastic bottles. The fact that the oxygen and nitrogen barrier properties were not included in the standard test indicators was related to the excessive thickness of the soft plastic infusion bottle wall (close to or even exceed the upper limit of the thickness of the detectable sample of the barrier test equipment, resulting in prominent test errors due to human factors). At that time, the detection technology of the overall oxygen gas transmission rate of the infusion bottle was still blank in China. The thickness problem does not exist for infusion bags. Therefore, in the standards for infusion films and bags issued in 2005 (YBB "three-layer coextrusion infusion films (I) and bags" and YBB "five layer coextrusion infusion films (I) and bags"), the requirements for barrier testing are not only limited to the water vapor permeability of the infusion bags, but also required to test the water vapor permeability, oxygen permeability and nitrogen permeability of the infusion films, Although the detection technology for the overall oxygen transmittance of infusion bags has been available, it is not involved in these standards for the time being because there is no support of national standards

3. The influence of nitrogen permeability measurement

the measurement of nitrogen permeability of membrane for infusion has always been concerned. But how to test the nitrogen permeability of the infusion membrane? At present, only the differential pressure method test equipment can detect the barrier performance of materials to a variety of gases (he, N2, air, O2, CO2, etc.). If the user can ensure the safety of gas source and tail gas treatment (especially for flammable, explosive and toxic gases), the test equipment can also be used to detect the permeability of some special gases (special attention must be paid to the operation safety!), And the test process is consistent with the ordinary oxygen test. The inability of isobaric method equipment to become a universal gas barrier test method is determined by its detection principle. Although this method can be used to detect the carbon dioxide transmittance of thin films, it is completely impossible to detect the nitrogen transmittance of thin films by isobaric method with current technology (nitrogen has been used as carrier gas). Therefore, considering the detection of nitrogen permeability, many inspection institutions and infusion bag manufacturers will choose the differential pressure method test equipment when purchasing gas barrier detection equipment

however, some people believe that nitrogen and oxygen are both conventional inorganic gases, and there will be some internal correlation between the transmittance of the same infusion membrane. Therefore, the permeability of nitrogen can be calculated by using a simple proportional relationship through the permeability of oxygen. This is not a formal method, so the proportion relationship used for estimation is often calculated by the calculation personnel themselves through some literature data. The correctness can be imagined, let alone the accuracy. A large number of test data also prove that the accuracy of the estimated data is very low. In fact, there are many factors that affect the gas transmittance of the film, and there are complex interactions between the material properties and the gas properties, plus environmental factors, etc. Therefore, this method of estimating through the proportional relationship is inherently wrong. The use of estimation methods will bring hidden dangers to the correct selection of materials. It is even more regrettable if the material selection errors are caused to meet this challenge

4. Prospects for infusion bag standards

the development of standards is often aimed at solving the outstanding problems existing in current products or methods. The outstanding problem of infusion bags is that the overall gas transmission rate of infusion bags due to thickness uniformity and sealing is larger than the overall gas transmission rate calculated from film detection data, and sometimes even more than twice as high. The author believes that the main reasons for this problem are as follows: first, for infusion bags (infusion bottles also have the same situation), uneven material thickness is a common situation. On the one hand, it may be affected by the processing technology, on the other hand, it is due to the needs of design. Therefore, there will be a large deviation between the calculation based on the average thickness and the measured data. Secondly, the sealing performance is a key factor. The fixation and sealing between the infusion bag and the infusion hose has always been a focus of attention. If the sealing performance is not high, the overall barrier performance of the infusion bag will be very low no matter how high the membrane barrier performance is. Third, the film area of the infusion bag is much larger than that of the film detection. After the test area is expanded, the probability of defects in the sample will increase, but this can better reflect the actual situation of the infusion bag. Therefore, the detection of the overall gas transmittance of infusion bags has become the leading development direction in the field of international barrier detection, but it can only be detected by isobaric method. However, it was mentioned earlier that the gas permeability test of infusion bags was not included in the relevant product standards, mainly because China's barrier testing technology was still at the level of film testing during the formulation of the standards, and there was no corresponding national standard support for container testing. At present, the formulation of the standard has been accelerated, and it has gradually reached the international advanced level. In addition, the domestic packaging container oxygen transmittance detection technology has been very mature. It is expected that the infusion bag gas transmittance will be included in the standard if there is no accident when the standard is revised. In view of this, some inspection institutions and infusion bag manufacturers have purchased or are preparing to purchase isobaric equipment

5. To sum up, the differential pressure method equipment must be used to meet the current detection needs of membrane gas barrier for infusion, but the isobaric method equipment is required to detect the oxygen permeability of infusion bags. The two kinds of equipment need two inputs, which not only increases the equipment configuration, but also the vibrating density of H3PO4 iron Li material is 1 (1) The cost of 4g/cm3 maintenance may also reduce the utilization of each equipment. Perme-dm2/330 double detection gas transmittance tester integrating two test methods has been successfully developed by Jinan Languang. The equipment can detect the two methods of differential pressure method and isobaric method, and can also test the oxygen transmittance of infusion bottles and bags. Its introduction provides a better choice for the detection equipment configuration of drug bag system and infusion bag manufacturers, and can optimize the equipment cost, data accuracy and equipment utilization

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