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Toxicological information

Carcinogenicity

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Administrative data

Endpoint:
carcinogenicity: dermal
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)

Test material

Constituent 1
Chemical structure
Reference substance name:
2,2',2''-nitrilotriethanol
EC Number:
203-049-8
EC Name:
2,2',2''-nitrilotriethanol
Cas Number:
102-71-6
Molecular formula:
C6H15NO3
IUPAC Name:
2,2',2''-nitrilotriethanol

Test animals

Species:
rat
Strain:
Fischer 344
Sex:
male/female
Details on test animals or test system and environmental conditions:
Male and female Fischer 344/N rats were obtained from Simonsen Laboratories (Gilroy, CA). On receipt, the rats were 4 weeks old. Animals were quarantined for 11 to 14 days and were 6 weeks old on the first day of the studies. Feed and water were available ad libitum. Rats were housed individually.

Administration / exposure

Route of administration:
dermal
Vehicle:
acetone
Details on exposure:
Based on the results of the earlier NTP studies, groups of 60 male and 60 female rats were topically administered 0, 32, 63, 125 mg/kg for males and 63, 125, and 250 mg/kg for females. Animals were topically administered triethanolamine in acetone.
Doses were applied 5 days per week for 103 weeks to an area extending from the animal’s mid-back to the dorsal intrascapular region; the site of application was clipped weekly during the studies.
Duration of treatment / exposure:
103 weeks
Frequency of treatment:
5 days per week
No. of animals per sex per dose:
60 males and 60 females. At 15 months, 10 males and 10 females were evaluated for organ weights and histopathology

Examinations

Sacrifice and pathology:
Complete histopathology was performed on all rats. In addition to gross lesions and tissue masses, the tissues examined included: adrenal gland, bone and marrow, brain, clitoral gland, epididymis, esophagus, heart, kidney, large intestine (cecum, colon, and rectum), liver, lung, lymph nodes (mandibular and mesenteric), mammary gland, nose, ovary, pancreas, parathyroid gland, pituitary gland, preputial gland, prostate gland, salivary gland, seminal vesicle, skin (lesions and unaffected skin from site of application; inguinal skin), small intestine (duodenum, jejunum,and ileum), spinal cord and sciatic nerve (if neurologic signs were present), spleen, stomach (forestomach and glandular stomach), testis, thymus, thyroid gland, trachea, urinary bladder, uterus.
Other examinations:
organ weights: right and left kidney and liver.
Statistics:
The probability of survival was estimated by the product-limit procedure of Kaplan and Meier (1958) and is presented in the form of graphs. Statistical analyses for possible dose-related effects on survival used Cox’s (1972) method for testing two groups for equality and Tarone’s (1975) life table test to identify dose-related trends.

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
survival rate of females in the 250 mg/kg group was slightly less than in the controls.
Mortality:
mortality observed, treatment-related
Description (incidence):
survival rate of females in the 250 mg/kg group was slightly less than in the controls.
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
At 15 month interim evaluation, absolute and relative kidney weights of females were greater than in controls.
Details on results:
Skin irritation was observed in dosed animals at site of application. Also acanthosis, inflammation and ulceration was observed in males (125 mg/kg) and females (all dose groups).
Relevance of carcinogenic effects / potential:
NA

Applicant's summary and conclusion

Conclusions:
No neoplastic effects observed and therefore classification as carcinogen is not warranted according to EU CLP and DSD.
Executive summary:

The survival rate of females in the 250 mg/kg group was slightly less than that of the vehicle controls. The mean body weight of females administered 250 mg/kg ranged from 9% to 12% less than that of the vehicle controls between weeks 73 and 93. Male and female rats receiving triethanolamine had irritated skin at the site of application; in dosed females, the site of application also had a crusty appearance. The number of animals in which these findings were observed increased with increasing dose. At the 15-month interim evaluation, the absolute left and right kidney weights and relative right kidney weight of females administered 250 mg/kg were significantly greater than those of the vehicle controls.

The incidence of acanthosis at the site of application in males administered 125 mg/kg and the incidences of acanthosis, inflammation, and ulceration in dosed females were greater than in the vehicle controls at the 15-month interim evaluation and at the end of the 2-year study. Males in the 125 mg/kg group also had greater incidences of inflammation and ulceration than the vehicle controls, and females receiving 125 or 250 mg/kg had greater incidences of epidermal erosion than the vehicle controls at 2 years.