Ethylene oxide sterilization is what?
A commonly used gas for chemical sterilizing medical equipment and products is ethylene oxide, sometimes known as EO or EtO. Ethylene oxide is a strong and quite penetrating alkylating agent. These qualities make it a successful sterilizing tool. At some doses, though, ethylene oxide can potentially induce cancer. Under vacuum and humidity, ethylene oxide kills microorganisms by means of exposure. EtO is either consumed entirely as 100% EtO or in concert with carbon dioxide.
Residuals for ethylene oxide (EtO)?
The main problems with ethylene oxide sterilization are its absorption into some materials and its reactivity with water or another material component to generate harmful leftover chemicals.
Respected ethylene oxide residuals are:
Ethylene oxide, sometimes known as EtO
Ethylene chlorohydrin (ECH)
Ethylene glycol (EG)
People as well as the surroundings suffer from these leftover chemicals. While ethylene chlorohydrin results from the interaction of ethylene oxide and chloride molecules, ethylene glycol is generated from ethylene oxide and water interactions.
Why and what is ethylene oxide residual testing?
At certain concentrations, ethylene oxide residuals are carcinogens and poisons to humans. Products sterilized with ethylene oxide must thus satisfy rigorous ethylene oxide residual limitations to ensure patient safety during the use of medical equipment and devices. Here one can find current ISO 10993-7 EtO residual limitations. Limits apply for ECH and EtO. Products in the EtO and ECH limits also fit EG limits. Based on the length of contact medical device makes with a patient, devices undergoing ethylene oxide (EO) sterilization can fit more than one EtO limit exposure category.
Which items call for ethylene oxide residuals testing?
Any object sterilized with ethylene oxide that comes into physical touch with a patient calls for EtO residuals testing. EtO residual testing is not necessary if your equipment or device does not come into direct touch with the patient.
If not clear-cut, so first you should find out whether your product calls for ethylene oxide residuals testing. Find out how to get your samples ready for testing and choose which ethylene oxide extraction technique is ideal for your device if it does call for ethylene oxide residuals testing.
USP 1115, USP 1116, and USP 1211 differ in what ways?
Unlike the aseptic production circumstances in USP 1116, USP 1115 covers non-sterile monitoring and manufacturing conditions free of the same constraints and quality requirements. USP 1211 addresses terminal sterilization, the third kind of sterilizing technique. Most terminally sterilized products satisfy the same sterility criteria as aseptically treated products by means of a last sterilization procedure ensuring a measurable safety level instead of aseptic processing. One can get terminal sterilization far less expensive than aseptic processes. Therefore, most items will satisfy FDA sterility criteria by means of non-sterile manufacture followed by a terminal sterilization processing instead of aseptic processing.
Method of ethylene oxide residual testing?
Two alternative approaches are applied for EtO residual analysis when deciding the kind and degree of EtO residuals in your medical equipment. The EtO residuals testing procedures are exhaustive extraction and simulated-use extraction. One does not need to evaluate a gadget using both testing approaches. Either simulated-use or complete extraction will suffice to satisfy ISO 10993-7 requirements for EtO residual testing.
Residual Ethylene Oxide Simulated-Use Extraction
Simulated-use extraction measures “residue levels available to the patient or user from devices during the routine use of a device with water extraction to simulate product use,” according to ISO 10993-7. This extraction technique is employed when only half, not the whole EtO sterilized equipment, will contact a patient. The simulated-use extraction will thus replicate the exposure of a patient to the proportion of the EtO sterilized device that the patient would come into contact with during regular product use. Using a transfer reduction factor technique helps one to estimate the EtO residual transferred to the patient for big, surface-contacting devices (such as gowns or drapes). Based on either a weight or a surface-area-proportional basis, the transfer reduction factor approach could be based on Annex E of ISO 10993-7.
Complete Extraction for Residual Ethylene Oxide
Extensive extraction, according to ISO 10993-7, entails the extraction of EtO “until the amount of EtO or ECH in a subsequent extraction is less than 10 % of that detected in the first extraction, or until there is no analytically significant increase in the cumulative residue levels detected.” When the entire device will come into touch with a patient and estimates the majority of EtO residue that a patient would be exposed to during device operation, this extraction technique is most suited. Usually every 24 hours, extractions are carried out until the requirements for restricted, extended, and permanent exposure—that is, for complete extraction—are satisfied. Complete extraction may not be feasible for big or complicated devices. In these cases, the EtO residuals can be extrapolated for the whole device by means of representative components of the device. Continue extraction until the increase in the cumulative yield of the analyte extracted is minimal relative to the analytical uncertainties, if the yield of the first extraction is small (as is the case with devices with little residue or devices that release analyte at a slow rate).
Calculating Tolerable Exposure Limits
EtO residuals are computed in several different ways. The computed average daily dose tolerated free from negative effects is known as tolerable exposure (TE). TE is stated daily in milligrams (mg/d). Tolerable intake (TI), body mass (BW), and use factor (UTF) all determine TE.
Tolerable Limit Equation:
TE = TI x BW x UTF
Where:
TI = tolerable intake (mg/kg/d)
BW = body weight (kilograms (kg))
UTF = utilization factor
And:
UTF = CEF x PEF
Where:
CEF = concomitant exposure factor
PEF = proportional exposure factor
BW is taken to be 70 kg when it is unknown. As said above, the UTF is the result of a concurrent exposure factor (which accounts for exposure to EtO from numerous devices) and a proportional exposure factor (which accounts for circumstances when a device is not used for the whole expected lifetime). Assumed to be 0.2 and 1 respectively are the concurrent exposure factor (CEF) and proportionate exposure factor (PEF).
Tolerable intake (TI) units are mg/kg/d. Scientific literature helps one to derive TI values. Thanks to the satisfactory clinical history since adopting the 1995 EtO residual limits, the TI device limitations from the 1995 edition of ISO 10993 have been kept for both the protracted and permanent exposure categories. Annex G of ISO 10993 has more details regarding TI value derivation.
For brief exposure—first 24 hours—current tolerable exposure limits are 4 mg/d of EO and 9 mg/d of ECH.
For prologued exposure—one day- thirty days of exposure—2.0 mg/d of EO and 2 mg/d of ECH.
For prologued exposure—more than thirty days—0.1 mg/d of EO and 0.4 mg/d of ECH
In Brief
Ethylene oxide sterilization is, all things considered, a substitute for conventional thermal sterilizing techniques (like steam). At some quantities, nevertheless, ethylene oxide residuals (EtO, ECH, and EG) are carcinogens and poisons to humans. Products sterilized with ethylene oxide that come into physical touch with patients must thus undergo ethylene oxide residual testing and satisfy tight ethylene oxide residual limits to maintain patient safety throughout product usage. Either simulated use or comprehensive extraction will be enough to satisfy ISO 10993-7 criteria for EtO residual testing when deciding the quantity and kind of EtO residuals in your medical device. When only a portion, not the whole EtO sterilized instrument will encounter a patient, the simulated-use extraction technique is applied. The simulated-use extraction will thus replicate the exposure of a patient to the proportion of the EtO sterilized device that the patient would deal with during regular product use. When the whole device will come into touch with a patient and estimates the majority of EtO residue that a patient would be exposed to during device operation, the exhaustive extraction approach is most suited. Tolerable exposure (TE) is the computed average daily dose (EtO and ECH) accepted free from negative effects. For limited exposure (first 24 hours of exposure), current tolerable exposure limits for EtO and ECH are 4 mg/d of EO and 9 mg/d of ECH; for prologued exposure (1 day-30 days of exposure), they are 0.1 mg/d of EO and 0.4 mg/d of ECH. All things considered, make sure you select a contract testing company that can offer suitable sterilizing validations and ethylene oxide residual testing for a particular medical device and product requirements.
