A Study on the Moisture Barrier Performance of a Multilayer Polymeric Medical Packaging System

Abstract

Abstract Moisture barrier performance of the packaging systems can be a critical design constraint when it comes to the protection of moisture-sensitive products. There are some techniques to control the moisture level of medical devices enclosed by the packaging system such as desiccants, moisture barrier layers, moisture sensors, etc. In order to design robust moisture-resistant polymeric packaging systems, it is imperative to understand the response of polymers to moisture. The moisture transportation in polymers can follow two different mechanisms namely, Fickian and non-Fickian behaviors. In Fickian dominant diffusion mode, water molecules can pass through the micropores in a polymer with very few hydrogen bonds formed between water molecules and polymeric molecular chains requiring less activation energy for the diffusion of water. On the other hand, in non-Fickian diffusion mode, there is a significant amount of hydrogen bonds formed between water molecules and molecular chains of polymers in which diffusion of water molecules is much slower due to the required higher activation energy to break the formed hydrogen bonds. In this study, a packaging system consisting of multilayers of Polychlorotrifluoroethylene (PCTFE) and modified Polyethylene terephthalate glycol (m-PETG) was primarily chosen because of its well-accepted moisture barrier performance in the pharmaceutical field. An experimental set-up was built to monitor the water vapor transmission through the packaging system in the designated extreme environmental conditions. The capacitance-based humidity sensors and thermocouples were employed to monitor the water vapor transmission through the packaging system in the environmental chamber. Additionally, the water vapor transmission rates (WVTR) for the complete packaging system were determined at certain relative humidity and temperature conditions by the ASTM F1249 standard test. A 2D computational model was built to simulate the moisture diffusion activity through the packaging system while assuming that Fickian diffusion is the dominant process. The computational model used the experimental data to determine the diffusion coefficients of the components of the packaging system model. Comparing the results, it appears that computational and analytical results are in good agreement. The results show that the 2D model can predict the moisture barrier performance of the packaging system under different environmental conditions. The computational model allows for gaining more insight into the effect of temperature and concentration gradient on the performance of the packaging system. Moreover, the effectiveness of each component of the packaging system on moisture performance can be well understood by the computational modeling approach. With this predictive engineering technique, the number of tests required to assess the moisture barrier performance of the packaging system significantly reduces and provides design flexibility during the packaging system development.