Water-based sterilization indicator composition
Water-based formulations comprising an indicating composition dispersed in water are described. The water-based indicating compositions include an organic Bi(III) compound, a sulfur source, a carbonate salt, and strontium hydroxide. Formulations further including a resin and/or an acidic additive are also described.
1. An indicator comprising:
(a) a substrate; and
(b) an indicating composition on the substrate comprising:
an organic Bi(III) compound;
a sulfur source;
a carbonate salt; and
strontium hydroxide;
wherein at least one of the organic Bi(III) compound and the sulfur source has solubility in water at 20° C. of less than 5 grams/100 ml.
2. The indicator of claim 1 , wherein the substrate comprises a surface and the indicating composition is on the surface of the substrate.
3. The indicator of claim 1 , further comprising a binder that secures the indicating composition to the substrate.
4. The indicator of claim 3 , wherein the binder is an acrylic resin.
5. The indicator of claim 1 , wherein the indicating composition comprises bismuth subcarbonate formed in situ.
6. The indicator of claim 1 , wherein both the organic Bi(III) compound and the sulfur source have solubility in water at 20° C. of less than 5 grams/100 ml.
7. The indicator of claim 1 , wherein at least one of the organic Bi(III) compound and the sulfur source have solubility in water at 20° C. of less than 1 gram/100 ml.
8. The indicator of claim 1 , wherein the organic Bi(III) is selected from the group consisting of bismuth subsalicylate, bismuth citrate, bismuth tartrate, and combinations thereof.
9. The indicator of claim 8 , wherein the acidic compound is non-polymeric.
10. The indicator of claim 1 , wherein the sulfur source is selected from the group consisting of sulfur, 1,3-diphenylthiourea, sodium thiosulfate, and combinations thereof.
11. The indicator of claim 10 , wherein the acidic compound is selected from the group consisting of citric acid, gallic acid, oxalic acid, and combinations thereof.
12. The indicator of claim 1 , wherein the carbonate salt is selected from the group consisting of lithium carbonate, magnesium carbonate, sodium carbonate, sodium bicarbonate, and combinations thereof.
13. The indicator of claim 1 , further comprising an acidic compound.
14. The indicator of claim 1 , wherein the indicator was prepared by the process of applying the indicating composition to the substrate and drying the indicating composition.