Visual chemical indicating composition for monitoring sterilization

Abstract

An indicator system and device for visually monitoring ethylene oxide sterilization by color changes of the indicating composition of the system upon sufficient and properly conditioned exposure of the composition to ethylene oxide provides a controlled method for indicating the effective sterilization of articles by ethylene oxide. The indicating composition of this invention undergoes color changes that are progressive with the conditions and periods of sterilization, such that a final and complete color change indicates the completion of an effective ethylene oxide sterilization. The indicating composition comprises a leuco precursor of an aryl methane dye selected from the groups herein defined; and an acidic constituent. Acidic organic compounds such as diphenolic acid (4,4-bis [4-hydroxyphenyl] pentanoic acid) are effective acid constituents because they enhance hue, develop color and stabilize the final color change. The indicating composition is integrated into an indicator system and device further comprising a substrate or carrier and polymeric binder, any one or more of which may also provide wholly or in part the acidic constituent of the indicating composition. The indicator device in the form of a coated ticket or tape is disposed with the articles to be sterilized within an ethylene oxide sterilization chamber. Contact with ethylene oxide is maintained until a final color change, usually from a definite color to substantially colorless, occurs in the indicator, signifying the completion of an effective ethylene oxide sterilization of the articles.

Dependencies are inferred from the claim text.