IP Library Granted Patent US 9,986,737
Granted Patent B2
US 9,986,737 · App. 15/060,869 · Granted Jun 5, 2018

Sterilization method

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Quick Facts
Patent No.
US 9,986,737
App. No.
15/060,869
Granted
Jun 5, 2018
Kind
B2
Abstract

A method of sterilizing a material, said method comprising the steps of: a) providing a sterilizing composition comprising (i) peracetic acid and (ii) a stabilizer selected from the group consisting of citric acid, isocitric acid, aconitic acid and propane-1,2,3-tricarboxylic acid; b) introducing such sterilizing composition into a hot gaseous stream to produce a peracetic acid vapor; and c) contacting such peracetic acid vapor with the material to be sterilized. The use of such an organic acid stabilizer results in an unexpected reduction in the amount of residue deposited on the heating surface employed to vaporize the sterilizing composition.

Claims (20)

1. A method of sterilizing a material, wherein the material is selected from the group consisting of metals, plastics, polymers and elastomers, the method comprising the steps of:

a) providing a sterilizing composition comprising (i) peracetic acid and (ii) a stabilizer selected from the group consisting of citric acid, isocitric acid, aconitic acid and propane-1,2,3-tricarboxylic acid;

b) introducing the sterilizing composition into a hot gaseous stream, wherein the temperature of the hot gaseous stream at the point of peracetic acid introduction is at least 5° C. higher than the dew point of peracetic acid, to produce a peracetic acid vapor; and

(c) contacting the peracetic acid vapor with the material to be sterilized.

2. The method of claim 1 , wherein the peracetic acid is present in a concentration of from about 15 to about 17 weight percent of the sterilizing composition; and the stabilizer is present in an amount between about 0.75 and about 1.5 weight percent of the sterilizing composition.

3. The method of claim 2 , wherein the stabilizer is present in an amount between about 0.9 and about 1.25 weight percent of the sterilizing composition.

4. The method of claim 3 , wherein the stabilizer is present in an amount between about 1.0 and about 1.2 weight percent of the sterilizing composition.

5. The method of claim 1 , wherein the peracetic acid is an aqueous equilibrium composition having a peracetic acid:hydrogen peroxide:acetic acid weight ratio selected from the group consisting of 12-18: 21-24:5-20; 15:10:36; 5:23:10; 21-23:6-10:33-36; and 35:10:15.

6. The method of claim 1 , wherein the peracetic acid is diluted to a concentration of less than 10,000 ppm prior to being introduced into the hot gaseous stream.

7. The method of claim 6 , wherein the peracetic acid is diluted to a concentration of less than 4,000 ppm prior to being introduced into the hot gaseous stream.

8. The method of claim 1 , wherein the stabilizer comprises citric acid.

9. The method of claim 8 , wherein the citric acid is diluted to about 250 ppm prior to being introduced into the hot gaseous stream.

10. The method of claim 1 , wherein the hot gaseous stream comprises sterile air, nitrogen, carbon dioxide or an inert noble gas.

11. The method of claim 1 , wherein the hot gaseous stream is heated to a temperature above about 250° C. prior to the introduction of the peracetic acid.

12. The method of claim 1 , wherein the hot gaseous stream is heated to a temperature above about 250° C. and is then cooled to a temperature of between about 80° C. and about 120° C. prior to the introduction of the peracetic acid.

13. The method of claim 1 , wherein the material to be sterilized is contaminated with bacteria or spores of Clostridium botulinum, Bacillis thuringensis , or Bacillus atrophaeus.

14. The method of claim 1 , wherein the material to be sterilized is contaminated with one or more of Staphylococcus, Enterococcus, Salmonella, Campylobacter, Pseudomonas, Candida, Rhizopus, Mucor , or Influenza.

15. The method of claim 1 , wherein the sterilizing composition further comprises one or more oxidants selected from the group consisting of chloroperbenzoic acid, perheptanoic acid, peroctanoic acid, perdecanoic acid, performic acid, percitric acid, perglycolic acid, perlactic acid and perbenzoic acid.

16. The method of claim 1 , wherein the sterilizing composition further comprises a sequestrant, a mineral acid catalyst, a surfactant, or a short chain fatty ester.

17. The method of claim 1 , wherein the contacting step is maintained for about 15 minutes to about 40 minutes.

Assignments (5)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 17, 2021
From: PEROXYCHEM LLC
To: EVONIK OPERATIONS GMBH
Reel/Frame 055624/0642 →
RELEASE OF SECURITY INTEREST IN PATENTS RECORDED AT R/F 050605/0305 Recorded Feb 3, 2020
From: BARCLAYS BANK PLC, AS ADMINISTRATIVE AGENT
To: PEROXYCHEM LLC
Reel/Frame 051777/0957 →
SECURITY INTEREST Recorded Oct 2, 2019
From: PEROXYCHEM LLC
To: BARCLAYS BANK PLC, AS ADMINISTRATIVE AGENT
Reel/Frame 050605/0305 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 4, 2016
From: ROVISON, JOHN M.; MITTIGA, RICKY; LAPHAM, DONALD; AN, WEIDONG
To: FMC CORPORATION
Reel/Frame 037891/0668 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 4, 2016
From: FMC CORPORATION
To: PEROXYCHEM LLC
Reel/Frame 037892/0052 →