US 2004O26517OA1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2004/0265170 A1 Read (43) Pub. Date: Dec. 30, 2004 (54) HYDROGEN PEROXIDE INDICATOR AND Related U.S. Application Data METHOD (63) Continuation of application No. 09/453,726, filed on (75) Inventor: David M. Read, White Bear Lake, MN Dec. 2, 1999, now Pat. No. 6,790,411. (US) Publication Classification Correspondence Address: (51) Int. Cl. ................................................. G01N 33/00 3M INNOVATIVE PROPERTIES COMPANY (52) U.S. Cl. .............................. 422/56; 252/408.1; 436/1 PO BOX 33427 ST. PAUL, MN 55133-3427 (US) (57) ABSTRACT The present invention provides a hydrogen peroxide indi cator that includes a Substrate on which is disposed an (73) Assignee: 3M Innovative Properties Company indicator composition that includes at least one of a Select group of colorants. As a result of contact with hydrogen (21)21) AppAppl. No.: 10,890,6121890, peroxide,erOXide, the colcolorants changehange color,col andd even bbecome colorless, thereby providing an indication of the presence of (22) Filed: Jul. 14, 2004 hydrogen peroxide. US 2004/0265.170 A1 Dec. 30, 2004 HYDROGEN PEROXDE INDICATOR AND Acid violet AX990, Basic red 15, Mordant red 19, Bro METHOD mopyrogallol red, and combinations thereof. 0007 Preferably, the colorant is selected from the group CROSS REFERENCE TO RELATED consisting of Ethyl violet, New fuchsin, Toluidine blue O, APPLICATIONS Luxol brilliant green BL, Disperse blue 1, Brilliant blue R, 0001. This is a continuation of patent application Ser. No. Quinea green B, Thionine, Meldolas blue, Methylene green, 09/453,726, filed on Dec. 2, 1999, which is now allowed, Lissamine green B, Alkali blue 6B, Brilliant green, Spirit hereby incorporated herein by reference. soluble HLK BASF, Victoria green S extra, Acid violet 17, Eriochrome black T, Eriochrome blue black B, D & C green BACKGROUND OF THE INVENTION no. 2, Spirit soluble fast RR, Spirit soluble fast red 3B, D & C red no. 22, Nitro red, Congo red, Brilliant cresyl blue 0002 Medical instruments, particularly surgical instru ALD, Arsenazo 1, Basic red 29, Bismarck brown R, Meth ments, are typically Sterilized prior to use using Steam or ylene violet, Methylene violet 3RAX- Mordant brown 1, other Sterilizing/disinfecting gases or liquids. A traditional Reactive black 5, Mordant brown 48, Acid brown AX987, Sterilization process uses Steam under pressure. Alternative Acid violet AX990, Mordant red 19, Bromopyrogallol red, Sterilization processes use ethylene oxide or hydrogen per and combinations thereof. oxide in vapor form as the Sterilant. 0008. In a preferred embodiment the present invention 0003. The use of hydrogen peroxide and other chemical provides a hydrogen peroxide indicator that includes a Vapor phase Sterilization techniques typically involve oper Substrate and an indicator composition disposed thereon, ating temperatures well below those associated with Steam wherein the indicator composition includes a binder, at least Sterilization. These “low temperature' technologies gener one colorant Selected from the group consisting of Malachite ally operate at temperatures below about 80 C., and often green oxalate, Crystal violet, Methyl violet 2B, Ethyl violet, below about 65 C. For hydrogen peroxide sterilization, the New fuchsin, Victoria blue B, Victoria pure blue BO, Sterilized goods are typically available for use shortly after Toluidine blue O, Luxol brilliant green BL, Disperse blue 1, the completion of the Sterilization cycle. This is because the Brilliant blue R, Victoria blue R, Quinea green B, Thionine, decomposition products (e.g., water and oxygen) are non Meldolas blue, Methylene green, Lissamine green B, Alkali toxic. The potency of the hydrogen peroxide may be aug blue 6B, Brilliant green, Spirit soluble HLK BASF, Victoria mented by the presence of electrical energy in the form of an green S extra, Acid violet 17, Eriochrome black T, Erio ionizing plasma field. chrome blue black B, D & C green no. 2, Spirit soluble fast 0004 Sterilization indicators are used to monitor whether RR, Spirit soluble fast red 3B, D & C red no. 22, Nitro red, a Sterilization proceSS has been performed. Sterilization Congo red, Brilliant cresyl blue ALD, Arsenazo 1, Basic red indicators typically include an indicator composition, car 29, Bismarck brown R, Methylene violet, Methylene violet ried on a Substrate, that changes color during the Sterilization 3RAX, Mordant brown 1, Reactive black 5, Mordant brown proceSS. Conventional indicators for hydrogen peroxide, 48, Acid brown AX987, Acid violet AX990, Basic red 15, however, often fade upon exposure to light. Thus, there is Mordant red 19, Bromopyrogallol red, and combinations Still a need for a Suitable indicator that includes a color thereof, and at least one colorant that does not change color change composition for indicating the vapor phase Steriliza upon contact with hydrogen peroxide vapor. tion of an article using hydrogen peroxide. 0009 Methods of monitoring a hydrogen peroxide ster ilization proceSS is also provides. These methods include SUMMARY OF THE INVENTION exposing an article to be Sterilized and the hydrogen perOX 0005 The present invention is directed to a method and ide indicators as described herein to hydrogen peroxide indicator for detecting the presence of hydrogen peroxide in Vapor. the vapor phase. The method and indicator are particularly well Suited for monitoring whether a hydrogen peroxide DETAILED DESCRIPTION OF PREFERRED Sterilization proceSS has been performed. EMBODIMENTS 0010. The present invention provides a hydrogen perox 0006 The present invention provides a hydrogen perox ide indicator that includes a Substrate on which is disposed ide indicator that includes a Substrate and an indicator an indicator composition that includes at least one of a Select composition disposed thereon, wherein the indicator com group of colorants. As a result of contact with hydrogen position includes at least one colorant Selected from the peroxide, the colorants change color, and even become group consisting of Malachite green oxalate, Crystal violet, colorless, thereby providing an indication of the presence of Methyl violet 2B, Ethyl violet, New fuchsin, Victoria blue B, hydrogen peroxide. Victoria pure blue BO, Toluidine blue O, Luxol brilliant green BL, Disperse blue 1, Brilliant blue R, Victoria blue R, 0011. In particular, the present invention is directed to a Quinea green B, Thionine, Meldolas blue, Methylene green, System for indicating exposure to a hydrogen peroxide vapor Lissamine green B, Alkali blue 6B, Brilliant green, Spirit Sterilization process. The indicator composition includes at soluble HLK BASF, Victoria green S extra, Acid violet 17, least one component that is transformed (typically, chemi Eriochrome black T, Eriochrome blue black B, D & C green cally transformed) in the presence of vaporous hydrogen no. 2, Spirit soluble fast RR, Spirit soluble fast red 3B, D & peroxide Such that the color of the composition changes. The C red no. 22, Nitro red, Congo red, Brilliant cresyl blue composition may include one or more components that ALD, Arsenazo 1, Basic red 29, Bismarck brown R, Meth change color upon contact with hydrogen peroxide, as well ylene violet, Methylene violet 3RAX, Mordant brown 1, as other components that do not change color upon contact Reactive black 5, Mordant brown 48, Acid brown AX987, with hydrogen peroxide. For example, the composition US 2004/0265.170 A1 Dec. 30, 2004 preferably includes a polymeric binder to aid in applying the 2, Spirit soluble fast RR, Spirit soluble fast red 3B, D & C composition to a Suitable Substrate. red no. 22, Nitro red, Congo red, Brilliant cresyl blue ALD, 0012 Indicators of the present invention are very useful Arsenazo 1, Basic red 29, Bismarck brown R, Methylene in indicating when an article has been exposed to hydrogen violet, Methylene violet 3RAX, Mordant brown 1, Reactive peroxide in the vapor phase. Significantly, indicators of the black 5, Mordant brown 48, Acid brown AX987, Acid violet present invention offer one a simple, yet effective means for AX990, Mordant red 19, Bromopyrogallol red, and combi indicating when a particular article has been Subjected to nations thereof. Sterilization using vaporous hydrogen peroxide. 0017 Another preferred group of colorants include the 0013 Preferably, the indicator compositions of the following: Malachite green oxalate, Methyl violet 2B, New present invention undergo a color change when exposed to fuchsin, Toluidine blue O, Luxol brilliant green BL, Quinea an atmosphere above an aqueous Solution containing 30 green B, Thionine, Meldolas blue, LiSSamine green B, Alkali weight percent (wt-%) hydrogen peroxide at 50° C. within blue 6B, Brilliant green, Victoria green S extra, Eriochrome a period of at least about one hour and/or a color change blue black B, Congo red, Bismarck brown R, Methylene when exposed to an atmosphere containing about 6 milli violet, Methylene violet 3RAX, Bromopyrogallol red, and grams/liter (mg/I) to about 7 mg/l hydrogen peroxide (in an combinations thereof. empty chamber, i.e., without articles to be sterilized) at a 0018 Suitable colorants become colorless or change to a pressure of about 8x10 Pascals (Pa) to about 13.3x10° Pa different color upon exposure to hydrogen peroxide vapor. and a temperature of about 45 C. to about 50 C. for a Preferred are those colorants that show good contrast period of at least about 50 minutes, which are typical between the initial color and the color after exposure to conditions within an empty commercial hydrogen peroxide hydrogen peroxide vapor. Examples include, Malachite plasma Sterilizer. More preferably, for use in conventional green oxalate, Methyl violet 2B, New fuchsin, Quinea green Sterilizers, the indicator compositions of the present inven B, Thionine, Meldolas blue, Lissamine green B, Alkali blue tion undergo a color change when exposed to an atmosphere 6B, Congo red, Eriochrome blue black B, Bismarck brown containing about 6 mg/l to about 7 mg/l hydrogen peroxide R, Methylene violet 3RAX, and combinations thereof. (in an empty chamber) at a pressure of about 8x10 Pa to 0019.