Nominations Reviewed in 2005

http://ntp.niehs.nih.gov/go/1123

Substances Recommended for Study:

Acetyl-L-carnitine hydrochloride and Α-Lipoic acid
Antimony trioxide
Butylparaben
1,3-Dichloropropanol
2,5-Dimercapto-1,3,4-thiadiazole
3-Dimethylaminopropylamine
Gum guggul extract
Imidazolidinyl urea
Permanent makeup inks
Usnic acid and Usnea herb
Vincamine

Substances for Which No Study is Recommended at this Time:

Antimony trisulfide
4-Bromofluorobenzene
2,6-Diaminopyridine
Garcinia cambogia extract

Chemicals studied by the NTP are selected mainly on the basis of human exposure, production levels, chemical structure, and available toxicological data. Selection of an agent for a study does not imply that the agent is hazardous or a potential carcinogen in laboratory animals; likewise, an agent not selected for toxicologic study by the Program should not be taken to mean that the agent is not potentially hazardous or potentially carcinogenic in laboratory rodents. Substances are identified by a common or generic name and CAS Registry No. where appropriate.

Note: A recommendation for "toxicological characterization" in this table includes studies for genotoxicity, subchronic toxicity, and chronic toxicity/carcinogenicity, as determined to be appropriate during the conceptualization and design of a research program to address toxicological data needs. Though other types of studies (e.g. metabolism and disposition, immunotoxicity, reproductive/developmental toxicity) may be conducted as part of a complete toxicological characterization, these types of studies are not listed unless they were specifically recommended.

For information, questions or comments, contact:
Dr. Scott A. Masten
Office of Chemical Nomination and Selection
Environmental Toxicology Program
National Institute of Environmental Health Sciences

P.O. Box 12233, MD A3-07
111 T.W. Alexander Drive
Research Triangle Park, NC
(919) 541-5710 (voice)
(919) 541-3647 (fax)

[ Send Email ]

Acetyl-L-carnitine hydrochloride and Α-Lipoic acid
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
Acetyl-L-carnitine hydrochloride and Α-Lipoic acid [5080-50-2],[62-46-4]	National Cancer Institute	Consumer exposure through increasing dietary supplement use; lack of adequate toxicological data	Subchronic toxicity studies (individual and combination studies)

Antimony trioxide
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
Antimony trioxide [1309-64-4]	National Institute of Environmental Health Sciences	Significant human exposure in occupational settings and lack of adequate two-year exposure carcinogenicity studies	Chronic toxicity and carcinogenicity studies Cardiotoxicity studies

Butylparaben
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
Butylparaben [94-26-8]	National Institute of Environmental Health Sciences	Widespread use in foods, cosmetics, and pharmaceuticals; potential reproductive toxicant; lack of adequate toxicological data	Toxicological characterization including reproductive toxicity studies

1,3-Dichloropropanol
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
1,3-Dichloropropanol [96-23-1]	National Institute of Environmental Health Sciences	High production volume and use; occurrence in foods; reproductive toxicity and carcinogenicity demonstrated but not adequately characterized	Toxicological characterization Metabolism and disposition studies Reproductive toxicity studies Carcinogenicity studies Coordinate studies with voluntary data development activities of the U.S. Environmental Protection Agency

2,5-Dimercapto-1,3,4-thiadiazole
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
2,5-Dimercapto-1,3,4-thiadiazole [1072-71-5]	Chemonics Industries, Inc.	Component of wildland fire retardant formulations; moderate production and industrial use; lack of adequate toxicological data	Genotoxicity studies Metabolism and disposition studies Subchronic toxicity studies

3-Dimethylaminopropylamine
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
3-Dimethylaminopropylamine [109-55-7]	National Cancer Institute	Significant and increasing use in personal care products; widespread industrial use; lack of information on chronic toxicity; evidence of toxicity in exposed workers	In vitro genotoxicity studies (in combination with a nitrosating agent) Dermal absorption and metabolism studies with focus on nitrosamine formation

Gum guggul extract
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
Gum guggul extract [No CAS No.]	National Institute of Environmental Health Sciences	Consumer exposure through increasing dietary supplement use; demonstrated metabolic and hormonal effects; lack of adequate toxicological data	Toxicological characterization

Imidazolidinyl urea
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
Imidazolidinyl urea [39236-46-9]	National Cancer Institute	Widely used preservative in personal care products; mutagenic potential; lack of adequate carcinogenicity data	Genotoxicity studies Dermal absorption studies Evaluation of potential degradation products (e.g., diazolidinyl urea and formaldehyde)

Permanent makeup inks
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
Permanent makeup inks [No CAS No.]	U.S. Food and Drug Administration	Rapidly growing practice in the United States; lack of adequate toxicological data; numerous human adverse event reports	For representative Premier Products True Color pigments: In vitro and in vivo allergenicity, photoallergenicity, and phototoxicity studies Chemical characterization studies

Usnic acid and *Usnea* herb
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
Usnic acid and Usnea herb [125-46-2],[No CAS No.]	U.S. Food and Drug Administration	Widely used in dietary supplement and personal care products; lack of adequate toxicological data; numerous human adverse event reports	Toxicological characterization including genotoxicity, pharmacokinetic, and developmental and reproductive toxicity studies In vitro mitochondrial toxicity studies

Vincamine
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
Vincamine [1616-90-9]	National Cancer Institute	Consumer exposure through dietary supplement use; suspicion of toxicity; lack of adequate toxicological data	Integrate into current NTP research program on QT interval prolongation

Antimony trisulfide
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
Antimony trisulfide [1345-04-6]	National Cancer Institute	Significant human exposure in occupational settings and suspicion of carcinogenicity	No additional studies at this time due to presumed lower workplace exposures relative to other antimony compounds

4-Bromofluorobenzene
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
4-Bromofluorobenzene [460-00-4]	National Institute of Environmental Health Sciences	High production volume and use; lack of adequate toxicological data; suspicion of toxicity based on chemical structure	Defer pending review of anticipated submissions on exposure and toxicity information to the U.S. Environmental Protection Agency and possible sponsorship in the High Production Volume Challenge Program

2,6-Diaminopyridine
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
2,6-Diaminopyridine [141-86-6]	National Cancer Institute	Moderate production and industrial use; lack of adequate toxicological data	Defer pending review of additional information on uses and potential exposure from hair dyes

*Garcinia cambogia* extract
Substance [CAS No.]	Nominated by	Rationale for Nomination	Study Recommendations*
Garcinia cambogia extract [No CAS No.]	National Cancer Institute	Consumer exposure through increasing dietary supplement use; lack of adequate toxicological data	Defer pending further review of recently published studies

Web page last updated on September 09, 2008