How To Calculate Allowable Limits For Stérilisation à l'oxyde d'éthylène
Ensuring patient safety is the highest priority in Ethylene Oxide sterilization. Medical devices must undergo rigorous EtO residual testing to verify they meet the strict limits defined by OIN 10993-7. These compounds—Ethylene Oxide (EO), Ethylene Chlorohydrin (ECH), and Ethylene Glycol (EG)—can be hazardous to health if not properly managed.
The Calculation of Allowable Limits (AL)
Le Allowable Limit (AL) is the maximum acceptable dose of a specific toxin (like EO) a patient can be exposed to. It is calculated based on tolerable intake and biological factors.
$$TE = TI \times BW \times UTF$$
$BW$: Body Weight (kg)
$UTF$: Utilization Factor
Current ISO 10993-7 Allowable Limits
| Exposure Category | Contact Duration | EO Limit (mg/d) | ECH Limit (mg/d) |
|---|---|---|---|
| Limited Exposure | First 24 Heures | 4.0 | 9.0 |
| Prolonged Exposure | 1 – 30 Days | 2.0 | 2.0 |
| Permanent Exposure | > 30 Days | 0.1 | 0.4 |
Methods of EtO Residual Analysis
To determine the residue levels, Ethylene Oxide sterilization technology relies on two primary extraction methods. Either method is sufficient for regulatory compliance:
This method replicates the actual patient exposure during normal product use. It extracts only the fraction of EtO residuals that the patient would likely interact with.
This method estimates the total majority of EtO residuals within the device through repeated extractions until negligible amounts remain.
Ensure Compliance with BOCON BCS Series
Achieving these strict Ethylene Oxide residual limits requires a high-performance sterilization cycle. BOCON’s Stérilisateurs ETO série BCS are engineered with advanced vacuum and heated aeration protocols to accelerate gas removal. Our equipment helps manufacturers streamline OIN 10993-7 compliance while maintaining rapid production turnarounds.
