Whitepaper: Study on The Stability of Ethylene Oxide Residues Solution During Transportation
ISO 11135-7 provides guidelines for the Ethylene Oxide (EO) sterilization process and highlights the need to monitor residual Ethylene Oxide (EO), Ethylene Chlorohydrin (ECH), and Ethylene Glycol (EG) levels. Accurate measurement ensures these residues stay within safe limits, reducing health risks associated with EO-sterilized devices. Residual testing involves extracting EO, ECH, and EG residues from devices followed by analysis using Gas Chromatography (GC) with a Flame Ionization Detector (FID), which precisely measures these volatile compounds.
ISO 10993-7:2008/AMD 1:2019 (Biological evaluation of medical devices- Part 7: Ethylene oxide sterilization residuals) emphasizes the importance of stability studies for EO solutions. Clause 4.4.3.1 Product Sampling, states that when shipping EO solution to testing lab, the shipment shall be done such that the fluid is kept at ice-cold temperatures (<10˚C) until arrival. Our laboratory frequently receives EO, ECH and EG residue solutions from customers. These solutions are sent in vials inside an icebox, packed with ice packs to keep them cold during transport. Ideally, the temperature inside the ice box should be maintained at <10˚C. Shipments usually arrive within 24 hours. However, certain circumstances may occur when the shipment will be held at customs This study will investigate how long the solutions stay viable in icebox. By determining their stability, we aim to provide better guidelines for handling and storing these residues, improving the accuracy of our tests and ensuring safety standards are met.
This study found that after 6 days in the icebox with temperatures of roughly 20˚C, the EO recovery is still within an acceptable range. However, this does not extend to ECH and EG residues, which have a recovery rate of less than 80% after Day 1, possibly due to the increase in temperature above 10˚C. Therefore, this study found that EO residue solutions must reach the testing laboratory within 24 hours for EO, ECH, and EG residue analysis to give reliable results.
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