Characterisation of polymer films for intravenous solvent bags packaging

Introduction
Pharmaceutical products use high-quality polymers, often combined in multilayer films to create packaging with the desired properties. However, despite their many advantages, these films have non-renewable sources, a short duration of use, are non-biodegradable, and lack recyclability. The current lack of waste management practices contribute to the high carbon footprint of the healthcare sector and thus to global warming.
The aim of this study is to understand how the impact of pharmaceutical products, from creation to end of life management, can be reduced using intravenous (IV) solvent bags as an example. To this end, the technical properties of the primary and secondary packaging films of IV solvent bags were characterised and compared with those of several alternative films. This enabled to identify polymer films with similar technical specifications that would consume less energy in production or are potentially recyclable.

Methods
Seven polymer films were studied: the standard film currently used for primary packaging of the solvent bags used in our university hospital, four alternative primary packaging films mainly composed of polypropylene (PP), the secondary packaging film of the solvent bags containing polyamide, and an alternative secondary packaging film made of PP. For each polymer film, the following characteristics were measured and compared: film thickness and the thickness of individual polymer layers using a digital thickness gauge and a digital microscope, film composition determined by Fourier Transform Infrared Spectroscopy (FTIR), thermal properties assessed by Differential Scanning Calorimetry (DSC), mechanical properties evaluated through tensile tests, water vapour permeation using Water Vapor Transmission Rate (WVTR) and optical transparency by haze measurement.

Results
The four alternative primary films exhibited physical, mechanical, and optical properties similar to those of the standard film. However, they showed lower water vapor permeability. One film contained a component with a melting point below 121°C, which could potentially lead to degradation during sterilization.
The secondary PP film met the performance characteristics of the standard secondary film though it was slightly less transparent.

Discussion/Conclusion
This analysis enabled the evaluation of the physical, chemical, thermal, mechanical, and optical properties of standard films used in the manufacture of IV solvent bags, as well as alternative primary and secondary films containing PP. The findings suggest that PP films comply with the target characteristics of standard films and offer an additional benefit of being a recyclable homopolymer. The carbon footprint of these polymers was evaluated in a separate study.

Keywords: polymers, polypropylenes, pharmaceutical preparations

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