Ethylene oxide exposure monitoring

Process Conditions for Ethylene Oxide. Exposure to ethylene oxide lasted 4, 6.5, and 15 hr. To keep the relative humidity at the necessary percent (1, 2, 3), water vapor was added to the chamber of the VDF. Exposure of the books to ethylene oxide occurred at either room temperature or at an elevated temperature. When the maximum temperature in the chamber in the latter case was set for approximately 40 °C, it took about 60 min to get to 33 °C and 3 hr to reach the maxium value. The temperature changes of the gas throughout the chamber after closing the chamber door were determined by placing a series of thermocouples both inside and outside of the books at different positions on the cart. A maximum difference of 11 °C was recorded upon entry of the gas into the chamber between a pair of these thermocouples positioned on the bottom shelf. The difference was reduced to 1°C after 8 min of exposure. Temperatures at the various positions were monitored throughout the entire experiment. 

In the case of ethylene oxide sterilization, rather more detail is included on the information expected in an MAA description of the sterilizer and associated facilities, the gas concentration used, bioburden monitoring and limits prior to exposure to gas, gas exposure time, temperature and humidity prior to exposure and during the exposure cycle, and the conditions under which ethylene oxide desorption is undertaken. 

Lawrence, R.M., Sweetman, G.M.A., Tavares, R. Farmer, P.B. (1996) Synthesis and characterization of peptide adducts for use in monitoring human exposure to acrylonitrile and ethylene oxide. Teratog. Carcinog. Mu tag.. 16, 139-148... 

If contact with the liquid or its solutions occurs, affected areas should be flushed thoroughly with water for at least 15 min. The areas should be observed for burns or resulting irritation. In case of inhalation of ethylene oxide, the victim should be moved to fresh air, an airway should be established, and respiration should be maintained as necessary. The victim should be monitored for irritation, bronchitis, and pneumonitis. If excessive exposure occurs, hospitalization and monitoring for delayed pulmonary edema is recommended. 

Fourier-transform infrared spectroscopy (FTIR) and pH measurements are the techniques most often adapted for in-line IPC. pH measurements are used for reactions that are run in water or have an aqueous component, e.g., an aqueous extraction. FTIR is especially good for monitoring continuous reactions [12] and reactions that would be dramatically changed by exposure to the atmosphere and temperature of the laboratory. Suitable reactions include low-temperature reactions, reactions run under pressure, reactions with gaseous or toxic materials (e.g., ethylene oxide), and reactions run under inert atmosphere. Further advantages of in-line assays are that no samples need to be prepared, and assay results can be generated within minutes. 

Sterilization by exposure to ethylene oxide is bounded by at least four variables gas concemratton, time of exposure, temperature, and humidity. It is also affected by product design, packaging design, and the composition of packaging materials. The shape, size, and materials of construction of individual sterilizers, the location of gas entry ports, and the presence or absence of forced circulation may all influence sterility assurance. There is no theory to describe these interactions. Validation and routine control of ethylene oxide sterilization processes boils down finally to the integration of all of these variables by reference to biological monitors. 

Chamber temperature should be controllable and monitored throughout all cycles. The temperature obtained in a load is a function of the initial product temperature and Its specific heat, the amount of steam injected, and the effectiveness of the insulation or the jacket at preventing heat loss. Temperature during the exposure phase of ethylene oxide sterilization cycles is not controlled by steam injection into the chamber as occurs in thermal sterilization. Loss of temperature may be compensated for by steam Injection into the jacket. The control probe is usually located within the chamber rather than within the jacket, and control of temperature is a good deal less fine than ini steam sterilizers because of the slower response through the jacket. Ethylene oxide sterilizers should be equipped with both jacket and chamber temperature indicators, and with chamber temperature recorders. Sterilizers should be specified with access... 

Although they have only been used in a limited number of cases, they have proved to give excellent results in special applications. For example, they are used in many plants and operations of the chemical industry for personal exposure monitoring of phosgene. Other examples include the determination of personal exposure doses of formaldehyde or ethylene oxide in clinical applications. 

Ethylene Oxide (ETO) Understanding OSHA s Exposure Monitoring Requirements (OSHA 3325—2007). 

A carbon dioxide sensor for monitoring levels in a closed exhalation anesthesia system was developed by Jordan (23). 7,10-dioxa-3,4-diaza-l,5,12,16-hexadecatetrol was prepared by mixing monoethanolamine, often used as a CO2 scrubber, with ethylene gylcol diglycidyl ether in a 2 1 ratio and was used as a coating. The respone was 391 Hz for 10% CO2, exposure time less than 30 sec, and complete recovery in less than 60 sec. No interferences were reported from nitrous oxide, halothane, or oxygen tested at normal anesthesia concentrations. 

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