Ethylene oxide sterilization, known as EO or EtO sterilization, is one of the most common ways in which packaged medical devices are sterilized. In an EtO sterilization process, water is introduced as a vapor because moisture enhances the effectiveness of EtO as a sterilant. Unlike medical-grade paper that absorbs moisture, Tyvek® is hydrophobic and does not absorb moisture, enabling a high moisture vapor transmission rate (MVTR) to be achieved. A high MVTR across the material to the package contents is an important factor in the EtO sterilization process.
Tyvek® withstands the rigors of EtO sterilization better than medical-grade papers, maintaining its superior strength and microbial barrier properties.
Another advantage that Tyvek® offers is that EtO does not readily adsorb on Tyvek® and is released more rapidly than from cellulosic materials such as medical-grade papers—including synthetic fiber-reinforced paper. In fact, residual analysis testing conducted according to ISO 10993-7 shows that there is significantly less EtO residual concentration in Tyvek® than in medical-grade papers after sterilization and aeration for 6, 12, 24 and 48 hours.
Tests have also been conducted to compare the strength and microbial barrier properties of Tyvek® before and after EtO sterilization. The data shows that there is no significant difference in tensile strength or microbial barrier between unsterilized and EtO-sterilized Tyvek®.