Dose-response assessments of Kathon biocide. (II). Threshold prophetic patch testing

Area of Science:

• Dermatology
• Toxicology
• Cosmetic Science

Background:

• Biocidal preservatives are crucial for product safety, preventing microbial contamination.
• Many effective preservatives carry a risk of skin sensitization.
• New preservative agents are needed to balance efficacy with safety.

Purpose of the Study:

• To evaluate the skin sensitization potential of a new isothiazolinone preservative mixture (Kathon CG).
• To determine safe usage concentrations for personal care, household, and industrial products.
• To assess the risk of clinical dermatoses associated with the new biocide.

Main Methods:

• Conducted 13 prophetic human repeat insult patch tests (HRIPT) on 1450 subjects.
• Tested Kathon CG at various concentrations, including 5, 6, 10, 12.5, 15, and 20 ppm.
• Monitored subjects for induction of skin sensitization and delayed contact hypersensitivity.

Main Results:

• No skin sensitization was observed at concentrations up to 15 ppm in 1321 subjects.
• Delayed contact hypersensitivity was induced in only 1 of 84 subjects at 12.5 ppm and 2 of 45 subjects at 20 ppm.
• The new preservative mixture demonstrated a very low sensitization potential at typical use concentrations.

Conclusions:

• Kathon CG is a safe and effective preservative agent for various product types.
• Use of this biocide at low concentrations for rinse-off products presents an extremely low risk of skin issues.
• The findings support the use of Kathon CG in formulations requiring robust microbial protection.