Fluid containers include glass bottles, soft plastic injection bottle (PP or PE), soft plastic injection bags (PVC and non-PVC). The initial injection liquid was packaged by bottles. Although improvement has been made several times but it could not get rid of the common defects of glasses such as fragileness, poor sealing, crumb and secondary air pollution.
1 Injection Liquid Bag Needs Material Barrier Tests
Oxygen is the main factor which causes the deterioration of injection liquid. If the oxygen barrier property of injection liquid package cannot perform well, it might cause the medicine to deteriorate before the guarantee date and the outcome is unimaginable. As a result, antioxidant, metal-chelator and inert gases are often employed in order to reduce the oxygen in the packages, postpone and prevent the liquid from oxygenation. Nitrogen is stable and often used with little carbon-dioxide as 'inert gases' to replace the air inside bags. If the barrier property against nitrogen is not strong enough, the nitrogen would permeate through bags. It might reduce the protection effect of inert gases and increase the oxygen in the package. Vapor permeation affects the concentration of medicines especially solute liquid for injection. Such situation will increase the difficulty of medicine concentration and vital risks. As the good barrier property of glass is well known, it can be considered that gases and vapor cannot permeate through glasses.
2 Requirements for Barrier Property Test in Medical Packaging Standards
he sealing performance of rubber plug and container became a focus (in plug standard). However, once the material is soft plastic the barrier property test is very necessary. For example, from 2002 the first version of soft plastic injection fluid bottle standard (YBB 00012002 'Low-density Polyethylene Injection Fluid Bottle' and YBB 00022002 'Polypropylene Injection Fluid Bottle'), it is required to test the vapor permeation rate and standards are given. In the meantime, other oral liquid soft plastic bottle standards also required vapor permeation rate test. Oxygen and nitrogen barrier properties were not listed in standard tests because the soft plastic injection fluid bottle is too thick (approaching or exceeding the barrier property test instrument's available test thickness up limit, which causes significant error).
3 The Influence of Nitrogen Permeation Rate Test
How to test the membrane? Currently only differential-pressure testing instrument can test the permeation property of many gases (He, N2, Air, O2, CO2 and so on). If the user can put the gas source under control and deal with the end gas (sometimes flammable, explosive or toxic), the instrument could be used to test the permeation property of some special gases (pay special attention to safety issue). The test process is the same with the test to ordinary oxygen. But equal pressure instrument cannot be used for the common-use gases permeation test
4 Perspectives on Infusion Liquid Bag Standards
The absence of gas permeation test of infusion bags is mainly because the technology at that moment only allow membrane barrier property test. There was no national standard for container test. Now the standards are getting close to international level and the container oxygen permeation rate test technology is very mature in China. The infusion bag permeation rate is expected to be included in the next standard revision. Consequently some test institutes and infusion bag manufacturers are ready to buy or buying equal pressure instruments.
5 the Development of Test Technology
Generally speaking, the current infusion membrane gas permeation test needs differential pressure instrument. But if it is the oxygen permeation rate test of infusion bags, it needs equal pressure instruments. Two investments to two instruments, it raised the maintenance fee and investment of equipments as well as lower the utilization of all equipments. PERME-DM2/330, double method gas permeation rate test instrument has been introduced by Labthink cooperation, Jinan. It is able to conduct differential pressure and equal pressure tests. Furthermore it can test the oxygen permeation rate of infusion bags and bottles. It is a better test equipment choice to medical packaging industry and infusion bag manufacturers. It can optimize the equipment cost, data accuracy and equipment utilization.