It is generally accepted that a film used for the containment of medical fluids needs to present highly transparent in order to allow visual inspection of their content. The transparency requirement is very important as medical fluids for intravenous application need to be absolutely clear and particle free and visual inspection will allow to determine whether or not contamination or undesired precipitation has taken place. It also allows to check for the turbidity of the solution.
The flexibility of the film is important for the drainage of IV bags, so that patients receive exact solution quantities as intended. It is clear that ideally the transparency and flexibility of the film are not affected by steam sterilization at the commonly used temperature of 121°C, nor by humidity or pressure. Other important requirements for a film used for manufacturing bags are heat sealability, puncture resistance, the ability to withstand sterilization (by autoclave or other method) and barrier properties.
Currently medical bags are typically made from films based on PVC. However, such PVC films are not free of low molecular weight additives, such as plasticizers, which can migrate from the IV bag into the medical fluid contained therein. Also PVC does not have high barrier properties and limits the use for high pH solution bags (at pH > 6.8 precipitation may occur). Therefore it is recommended for several applications to replace PVC by inert materials such as polyolefin materials.