NTP technical report on the toxicology and carcinogenesis study of triclosan (CASRN 3380-34-5) administered dermally to B6C3F1/N mice / National Toxicology Program (U.S.).

Format:

Book

Author/Creator:

National Toxicology Program (U.S.), author, issuing body.

Series:

NTP Technical Report ; Number 604

Language:

English

Subjects (All):

Carcinogenicity testing.

Physical Description:

1 online resource : illustrations.

Other Title:

NTP technical report on the toxicology and carcinogenesis study of triclosan

Place of Publication:

Research Triangle Park, North Carolina, USA : National Toxicology Program, Public Health Service, U.S. Department of Health and Human Services, 2024.

Summary:

TWO-YEAR STUDY IN MICE: Triclosan is a broad-spectrum antimicrobial agent to which humans are widely exposed. Very limited data are available regarding the dermal toxicity and the carcinogenic potential of triclosan. In this study, groups of 48 male and 48 female B6C3F1/N mice were untreated or were dermally administered 0 (vehicle), 1.25, 2.7, 5.8, or 12.5\smg triclosan/kg body weight/day (mg/kg/day) in 95% ethanol, 7\sdays per week for 2\syears. Vehicle control animals received 95% ethanol only; untreated, naive control mice were not dosed. There were no significant differences in survival among the groups. The highest dose of triclosan decreased the body weights of mice in both sexes, but the decrease was ≤8%. Minimal to mild epidermal hyperplasia (males and females), suppurative inflammation (males only), and ulceration (males only) were observed at the site of application in the dosed groups, with the highest incidence occurring in the 12.5\smg/kg/day groups. In male and female mice, no skin neoplasms were identified at the site of application. In male mice, the two highest dosed groups (5.8 and 12.5\smg/kg/day) had significantly increased incidences of hepatocellular carcinoma, and the incidences occurred with a positive trend relative to the vehicle control group. A positive trend in the incidence of hepatocellular adenoma or carcinoma (combined) was observed in male mice, with significantly increased incidences in the ≥2.7\smg/kg/day group. Female mice had a positive trend in the incidence of pancreatic islet adenoma. CONCLUSIONS: Under the conditions of this 2-year dermal study, there was some evidence of carcinogenic activity of triclosan in male B6C3F1/N mice based on the increased incidences of hepatocellular adenoma or carcinoma (combined). There was equivocal evidence of carcinogenic activity of triclosan in female B6C3F1/N mice based on higher occurrences of pancreatic islet adenomas. Dermal administration of triclosan resulted in increased incidences of nonneoplastic epidermal lesions at the site of application in male and female mice.SYNONYMS: 2,4,4-trichloro-2-hydroxydiphenyl ether, 2,4,4'-trichloro-2'-hydroxydiphenyl ether, trichloro-2'-hydroxydiphenyl ether TRADE NAMES: Irgasan, CH 3565, Irgasan CH 3565, Irgasan DP300, Ster-Zac, Tinosan AM110 Antimicrobial, Invasan DP 300R, Invasan DP 300 TEX, Irgaguard(r) B 1000, VIV-20, Irgacare MP, Lexol 300, Cloxifenolum, Aquasept, Gamophen, Vinyzene DP 7000, Vinyzene SB-30, Sanitized Brand, Microbanish R, Vikol THP, Ultra-Fresh, Microban Additive "B," AerisGuard, and Sapoderm.

Contents:

Foreword

Collaborators

Contributors

Explanation of Levels of Evidence of Carcinogenic Activity

Peer Review

Publication Details

Acknowledgments

Introduction

Chemical and Physical Properties

Production, Use, and Human Exposure

Biological and Toxicological Properties

Study Rationale

Materials and Methods

Procurement and Characterization

Preparation and Analysis of Dose Formulations

Analysis of Triclosan in Experimental Background Materials

Animal Source

Animal Welfare

Two-year Study

Statistical Methods

Quality Assurance Methods

Results

Data Availability

Mice

Benchmark Dose Analysis

Discussion

Conclusions

References

Appendix A. Chemical Characterization and Dose Formulation Studies

Appendix B. Ingredients, Nutrient Composition, and Contaminant Levels in NTP-2000 Mouse Ration

Appendix C. Sentinel Animal Program

Appendix D. Benchmark Dose Analysis

Appendix E. Supplemental Data.

Notes:

Description based on publisher supplied metadata and other sources.