Ethylene oxide gas

Low humidity ethylene oxide gas sterilisa tion procedures and moisture-proof packaging for polyglycoHc acid products are necessary because of the susceptibihty to degradation resulting from exposure to moisture and gamma sterilisation. 

Such sterilization procedures (see also Chapter 20) may include heat treatment, filtration, irradiation, recrystallization flxm a bactericidal solvent such as an aleohol, or for dry products where eompatible, ethylene oxide gas. If the raw material is only a minor constituent and the final product is adequately preserved either by lack of chemically... 

Closure liners of pulpboard or cork, unless specially treated with a preservative, foil or wax coating, are often a source of mould contamination for liquid or semi-solid products. A closure with a plastic flowed-in linear is less prone to introduce or support microbial growth than one stuck in with an adhesive, particularly if the latter is based on a natural product such as casein. If required, closures can be sterilized by either formaldehyde or ethylene oxide gas. 

The British Pharmacopoeia (1993) recognizes five methods for the sterilization of pharmaceutical products. These are (i) dry heat (ii) heating in an autoclave (steam sterilization) (iii) filtration (iv) ethylene oxide gas and (v) gamma or electron radiation. In addition, other approaches involving steam and formaldehyde and ultraviolet (UV) light have evolved for use in certain situations. For each method, the possible permutations of exposure conditions are numerous, but experience and product stability... 

Ethylene oxide gas is highly explosive in mixtures of >3.6% vN in air, in order to reduce this explosion hazard it is usually supplied for sterilization purposes as a 10% mix with carbon dioxide, or as an 8.6% mixture with HFC 124 (2 chloro-1,1,1,2 tetrafluoroethane) which has replaced fluorinated hydroearbons (freons). Alternatively, pure ethylene oxide gas can be used at below atmospheric pressure in sterihzer chambers from which all air has been removed. 

The operation of an ethylene oxide sterilizer should be monitored and controlled automatically. A typical operating cycle for pure ethylene oxide gas is given in Fig. 20.7, and general eonditions are summarized in section 10. 

Ethylene oxide Gas concentration 800-1200 mgl 45-63°C 30-70% relative humidity 1-4 hours sterilizing time... 

N 22.21% oil - no props given was obtd by passing ethylene oxide gas thru stirred pro-pylenedinitramine in water a small amt of NaOH (Ref 2)... 

Potassium hydroxide absorbed into powdered polycaprolactam and heated with ethylene oxide gas in chlorobenzene at 80° C for 7 hrs is the process claimed... 

The critical temperature above which ethylene oxide gas cannot i be liquefied has been listed variously as 192° and The... 

Dolovich J, Sagona M, Pearson F, Buccholz D, Hiner E, Marshall C. Sensitization of repeat plasmapheresis donors to ethylene oxide gas. Transfusion 1987 27(l) 90-3. 

Leitman SF, Boltansky H, Alter HJ, Pearson FC, Kaliner MA. AUergic reactions in healthy plateletpheresis donors caused by sensitization to ethylene oxide gas. N Engl J Med 1986 315(19) 1192-6. 

Ethylene oxide gas is highly explosive in mixtures of >3.6% v/v in air in order to reduce this explosion hazard it is usually supplied for sterilization purposes as a 10% mix with carbon dioxide, or as an... 

Z. Zhu, I. P. Matthews, and W. Dickinson, Specificity, accuracy, and interpretation of measurements of ethylene oxide gas concentrations during sterilization using a microwave spectrometer. Rev. Sci. Instrum. 68(7), 2883-2890 (1997). 

Heat-sensitive materials may be sterilized by radiation, providing the product and its container are not radiation sensitive. It is particularly used with plastics, and more widely used with containers than with products. An alternative is ethylene oxide gas. This presents problems in that the gas must be brought into contact with the cell walls of contaminating bacteria. Ethylene oxide is highly reactive and can only be used when it can be proved not to react with the product. 

---