• Journal of Environmental Health Sciences
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• v.8 no.1
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• pp.81-97
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• 1982

Ethylene oxide gas has been used as a cold sterilant for heat-sensitive medical equipments and as a fumigant for food for more than 30 years, and it is used more widely than radiation although radiation sterilization has made significant inroads in recent years. But according to recent studies of toxicities such as mutagenicity, haemolytic effect and possible carcinogenicity of Ethylene oxide (ETO) and its two main reaction products, Ethylene chlorohydrin (ETCH) and Ethylene glycol (ETG), Environmental Protection Agency in U.S.A. has suggested some regulations on residual gas in drug products and medical devices for human use. The mutagenic activity of ETO compared with that of X-ray has an equivalency of 1 ppm/hr for ETO as compared to 20 mrad for X-ray, and one could suggest the present maximum allowable concentration for ETO (50 ppm) should be 400 times lower than the radiation standard (2.5 mrad/hr). Although radiation sterilization has advantages of simplicity of operation and complete reliability, changes of physico-chemical properties with possible formation of toxic substances may occur. It is therefore necessary to make some regulations of our own for residual toxicities orginated from each sterilization method.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.19 no.3
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• pp.287-299
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• 1997

Procurement, cutting, cleansing, freezing, freeze-drying, and demineralization of the allogeneic bone must be made under the germ-free stable condition without bacterial and/or viral contamination. Even thought the bone is procured under the germ free condition, we must have confidence on disinfection of all the solutions that come in contact with tissue during the whole procedure. Lots of antibacterial agents have been introduced for chemical sterilization. Recently ethylene oxide gas sterilization or radiation sterilization is frequently selected as a secendary sterilization procedure. The biological and biochemical response of the graft material differs with the type and concentration of the sterilizing agents, and various toxic reactions have been reported due to the graft material itself and the substance released by the chemicals. The authors conducted the Millipore filter test to observe the toxic effect on L929 fibroblasts according to the effect on activity of succinate dehydrogenase, during the secondary sterilization of the demineralized allogeneic bone powder with irradiation or ethylene oxide gas. The result were as follows : 1. Around the copper disk, positive control group, 10mm diameter discoloration was observed. 2. As same as the negative control group, the disk showed no discoloration. 3. The demineralized allogeneic bone which was sterilized with ethylene oxide gas or irradiation showed no cytotoxicity. 4. From this results, it is suggested that treatment with ethylene oxide gas or irradiation should be effective to sterilize the deminineralized allogeneic bone.

• Journal of Sensor Science and Technology
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• v.29 no.3
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• pp.211-214
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• 2020

Chlorine dioxide is very effective gas for sterilization or disinfection (in manufacturing), and does not produce harmful by-products after use. However, if its concentration exceeds 10 %, it become explosive and cannot be compressed or stored. Therefore, it is necessary to measure its concentration. In this study, the concentration of chlorine dioxide with a high oxidizing strength was measured using a metal oxide sensor. The sensor was a commercially available TGS series from Figaro. The sensitivity of the sensor was inversely proportional to a low concentration of chlorine dioxide gas below 6 ppm and returned to the initial resistance at about 6 ppm. When the gas concentration reached multiples of 10 ppm, resistance of the sensor increased to several megaohms.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.21 no.2
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• pp.141-150
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• 2014

Purpose: This was a study on the expiration date of Ethylene Oxide (EO) gas sterilization and effects of the environmental factors of temperature, humidity and type of cabinet in sterile goods storage area on the expiration date. Methods: Sterile goods storage areas from 13 departments in one hospital were selected and 455 EO gas sterilization samples were prepared and kept in those areas over the 14 months of the study. Each sample was tested with a microbiological culture in the laboratory every week. If the result was positive, the sample was regarded as contaminated. The researcher visited once a month to check the temperature, humidity and type of cabinet. Results: With the exception of 1 sample which was positive at 56th week. 454 samples were confirmed as negative. The environment of the samples storage area was measured monthly. The annual average temperature was $24.2{\pm}1.6^{\circ}C$, and the mean relative humidity $34.7{\pm}15.2%$. The types of cabinet were 7 open and 6 closed. Conclusion: The results of the microbiological culture at 13 months showed that none of the samples were contaminated. Therefore the hospital's existing Expiration Date can be extended from 6 months to 13~14 months.

• Journal of Radiation Industry
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• v.8 no.2
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• pp.133-140
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• 2014

The sterilization of health care products is widely used to choose conventional Ethylene Oxide gas sterilization in South Korea. But the method has brought serious issues because of the toxic residual gas and global warming of $CO_2$ evacuation after the sterilization process. This study is carried out to confirm the application possibility of gamma sterilization instead of Ethylene Oxide in sanitary aid products. Four kinds of products (gauze, menstrual pad, bandage, menstrual tampon) were treated with gamma irradiation of 15 kGy, then analyzed the achievement of the sterility assurance level (SAL) $10^{-6}$ through BI test. The cytotoxicity of accelerated samples of 6 months elapse evaluated by means of colony forming rate at various concentration of the extracts. pH and UV measurements at extract concentrations were tested according to the MFDS (Ministry of food & drug safety) guideline to verify a stability & safety of product sterilized. The results revealed that the extracts did not show any significant changes in cytoxicity assay as well as pH and UV values by gamma sterilization. All extract concentration was observed high cell viability, pH and UV values were calculated within the acceptable range prescribed by the guideline. It indicates that gamma sterilization could effectively substitute for conventional sterilization such as Ethylene Oxide sterilization in the sanitary aid products.

• Air Cleaning Technology
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• v.23 no.3
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• pp.34-43
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• 2010

In most productive facility of pharmaceutical companies, the fumigation using formaldehyde gas has been put into operation. Because formaldehyde gas is so bactericidal as to sterilize bacterial spore which can not be sterilized with usual disinfectants, it has been used for fumigation in many facilities such as facility of experimental animals, research institute and productive facility of pharmaceutical companies which are required to be high level of biological clean. However, the use of formaldehyde is recently under the strict management because of its causing of sick house and carcinogenesis. We introduce the conditions of sterilization using formaldehyde gas, the examples of sterilization using formaldehyde gas in a pharmaceutical manufacture and the problems of use of formaldehyde against environments and health. Further, we describe the characteristics and future subjects of the sterilization method using gasified oxidants such as hydrogen peroxide, peracetic acid and chlorine oxide.

• International Journal of Industrial Entomology and Biomaterials
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• v.42 no.2
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• pp.46-50
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• 2021

When 4-hexylresorcinol (4HR) incorporated silk mat is used for clinical application, sterilization process is essential. In this study, 4HR incorporated silk mat was sterilized with ethylene oxide (EO) gas or autoclave, and then antibacterial property was evaluated. For the examination of micro-structure after the sterilization, scanning electron microscopic (SEM) exam and Fourier Transform Infrared (FT-IR) spectroscopy were also done. There was no gross difference after sterilization in SEM exam and FT-IR spectra. Antibacterial property of 4HR was also maintained after the sterilization. In conclusion, EO gas or autoclave did not damage the antibacterial property of 4HR in the silk mat.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.1
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• pp.68-86
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• 1995

This study was conducted at five Ethylene Oxide(EO) sterilizing processes in hospitals located in Seoul from August 8 to August 30, 1994. The main purposes of this study were to assess the TWA(Time Weighted Average) and short term exposures to EO and to evaluate factors affecting EO concentrations in sterilizing room. Results are summarized as follows. 1. The TWA concentrations of the sterilizing operators ranged from <0.005ppm to 3.04ppm and those of two sterilizing rooms out of five exceeded 1ppm, the Korean and ACGIH standards. 2. When the door of the sterilizer is opened at the end of the sterilization cycle, the short term concentrations of operators ranged from <0.005ppm to 11.4ppm, and those of three sterilizing room out of five exceeded 5ppm, the ACGIH short term exposure limit(STEL). The short term concentrations of area samples ranged from 0.24ppm to 49.2ppm and those of four sterilizing room out of five exceeded 5ppm. 3. Factors affecting EO exposure level were aeration type, the location of storage site for sterilized item, amount of gas, use period of sterilizer(p<0.005). 4. Following recommendations are suggested to minimize exposure to EO. The use of EO gas should be reduced by using another available sterilization methods, and the sterilizers and gas tank storage site should be isolated from, other work areas. Combination of local and general ventilation system should be installed. Metal carts or baskets for sterilization load should be used, and work environment and medical monitoring should be performed regularly.

• Journal of Korean Society of Archives and Records Management
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• v.1 no.1
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• pp.231-243
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• 2001

The sterilization method of records by fumigation using mixed gas of methyl bromide(MB) and ethylene oxide(ETO) has been generally used as a way to protect biological deterioration by microorganisms and insects. In this study, we confirmed sterilization effect of MB and ETO [86 : 14(Vol.%)] on and analyzed toxicity on microorganisms isolated from records. To analyze sterilization effect of fumigation on microorganisms and insect, we have fumigated microorganisms and insect with a various amounts mixed gas of MB and ETO, and various exposure time. Insect was sterilized at all experimental conditions. In microorganisms, sterilization effect was detected only when the mixed gas was treated at $120g/m^3$ concentration for at least 24 hrs. To test the possibility of isolated microorganisms as a threat to human health, it was investigated that toxicity test using yeast, radish and cancer cells on microorganisms. Only Aspergillus oryzae had an inhibition effect on growth of yeast. radish and cancer cells, respectively. These results demonstrate that sterilization effect can occur at low concentrations of the mixed gas on insect but requires higher concentrations of the mixed gas on microorganisms. In addition to, it is suspected that the possibility of the microorganism as a threat to human health is little.

• Restorative Dentistry and Endodontics
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• v.30 no.2
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• pp.121-127
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• 2005

A variety files made of stainless steel (S-S) or nickel-titanium (Ni-Ti) are used during endodontic treatment. The purpose of tt)is study was to evaluate the corrosion susceptibility of S-S and Ni-Ti endodontic files. Three brands of files were used for this study: $K-flex^{(R)}$ S-S files (Maillefer, USA), $Profile^{(R)}$ Ni-Ti files (Maillefer, USA), $K-3^{(R)}$ Ni-Ti files (SybronEndo. USA). 120 files of each brands (21mm, ISO size $\#20$) were divided into 12 groups according to 1) sterilization methods using Autoclave or Ethylene Oxide (E-O) gas, 2) Irrigation solutions using $5.25\%$ NaOCl or Saline, 3) the number of sterilization (1, 5, 10 times), After above procedures, each of the files was inspected by three examiners with a light microscope and camera at X25. Each file was judged and ranked according to the following criteria: 0;, no corrosion, 1; mild corrosion, 2; moderate corrosion, and 3; severe corrosion. The files of high score were examined under the Scanning Electron Microscope. Data were statistically analyzed with the Kruskal-Wallis test (p < 0.05). Most of the ten time-autoclaved files had showed mild to moderate corrosion. But, one or five time-autoclaved files did not show corrosive surface. NaOCl treatment and E-O gas sterilization did not influence on corrosion. There was a significant difference in corrosion susceptibility between sterilization methods and the number of autoclaving. However, there was no significant difference between brands and file materials.