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Repeated dose toxicity: dermal

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Administrative data

Endpoint:
chronic toxicity: dermal
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Read across study hence maximum reliability rating of 2 assigned according to ECHA guidance, although study is well documented, meets generally accepted scientific principles, acceptable for assessment
Cross-referenceopen allclose all
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2001

Materials and methods

Principles of method if other than guideline:
A two-year dermal study was conducted in rat to evaluate the carcinogenic potential of the test substance.

GLP compliance:
yes
Limit test:
no

Test material

Constituent 1
Reference substance name:
Amides, C8-18 and C18-unsatd., N,N-bis(hydroxyethyl)
EC Number:
268-935-9
EC Name:
Amides, C8-18 and C18-unsatd., N,N-bis(hydroxyethyl)
Cas Number:
68155-07-7
IUPAC Name:
68155-07-7
Constituent 2
Reference substance name:
Amides, C8-18 and C18-unsatd., N,N-bis(hydroxyethyl)
IUPAC Name:
Amides, C8-18 and C18-unsatd., N,N-bis(hydroxyethyl)
Test material form:
liquid: viscous
Details on test material:
- Name of test material (as cited in study report): Coconut oil acid diethanolamine condensate
- Physical state: Viscous yellow liquid
- Composition of test material, percentage of components: Composed primarily of diethanolamides of coconut oil acids, with unreacted diethanolamine, alkanolamides of unsaturated acids, and amine salts of the acids. The polar nitrosamine, N-nitrosodiethanolamine, was detected at a concentration of 219 ppb
- Lot/batch No.: 1G01742286
- Stability: Unstable when stored in glass tubes for 2 wk at 60°C
- Storage condition of test material: At room temperature, protected from light, in amber glass bottles sealed with Teflon- lined caps

Test animals

Species:
rat
Strain:
Fischer 344
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Taconic Laboratory Animals and Services, (Germantown, NY)
- Age at study initiation: 6 wk
- Housing: Housed individually in Polycarbonate cages (Lab Products, Inc., Maywood, NJ)
- Bedding: Sani-Chip heat-treated hardwood chips (P.J. Murphy Forest Products Corp., Montville, NJ)
- Diet : NIH-07 open formula pelleted diet (Zeigler Brothers, Inc., Gardners, PA), ad libitum
- Water : Tap water (Columbus municipal supply), ad libitum
- Acclimation period: 11 to 12 d

ENVIRONMENTAL CONDITIONS
- Temperature : 20.0 -23.9 °C
- Humidity : 33-70 %
- Air changes : 10/hr
- Photoperiod : 12 h dark/12 h light

IN-LIFE DATES: From: Feb. 1, 1993 To: Jan. 31, 1995

Administration / exposure

Type of coverage:
open
Vehicle:
ethanol
Details on exposure:
The test substance formulation was applied to the shaved skin of test animals. No further details provided.


Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Dose formulations were analysed approximately every 2 months using HPLC. In addition to dose formulation analysis prior to dosing, samples collected after dosing (animal room samples) were analysed periodically.
Duration of treatment / exposure:
104 wk
Frequency of treatment:
Five exposures per week
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 50 or 100 mg/kg bw/d (0, 85, or 170 mg/mL in ethanol)
Basis:
nominal per unit body weight
No. of animals per sex per dose:
50/sex/dose
Control animals:
yes, concurrent vehicle
Details on study design:
Dose selection rationale: Doses of 200 or 400 mg/kg bw/d in the 14 wk study were associated with reduced mean body weights, mild anemia, and significantly increased incidences and severities of lesions of the skin at the site of application. Therefore, these doses were considered inappropriate for a 2-year study. At 100 mg/kg bw/d, the incidences of skin lesions, especially ulceration, were less than at 200 mg/kg bw/d, and in general, the severities were minimal to mild. Therefore, 100 mg/kg bw/d was selected as the high dose for this 2-yr study.

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Observed twice daily


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Clinical findings were recorded initially, at 4 wk intervals during the study, and at the end of the study


DERMAL IRRITATION (if dermal study): Yes


BODY WEIGHT: Yes
- Time schedule for examinations: Animals were weighed initially, weekly during Week 1 through 13, at 4 wk intervals thereafter, and at the end of the studies


Sacrifice and pathology:
SACRIFICE: Carbon dioxide asphyxiation
GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes, Complete histopathology was performed on all rats. In addition to gross lesions and tissue masses, the following tissues
were examined: adrenal gland, bone and marrow, brain, clitoral gland, esophagus, heart, large intestine (cecum, colon, rectum), small intestine (duodenum, jejunum, ileum), kidney, liver, lung, lymph nodes (mandibular and mesenteric), mammary gland, nose, ovary, pancreas, parathyroid gland, pituitary gland, preputial gland, prostate gland, salivary gland, skin, spleen, stomach (forestomach and glandular), testis (and
epididymis and seminal vesicle), thymus, thyroid gland, trachea, urinary bladder, and uterus
Statistics:
Survival Analyses: The probability of survival was estimated by the product-limit procedure of Kaplan and Meier (1958). Possible dose-related effects on survival were analysed by Cox’s (1972) method for testing two groups for equality and Tarone’s (1975) life table test to identify dose-related trends. All reported P values for the survival analyses were two-sided.
Analysis of Neoplasm and Nonneoplastic Lesion Incidences: The Poly-k test (Bailer and Portier, 1988; Portier and Bailer, 1989; Piegorsch and Bailer, 1997) was used to assess neoplasm and nonneoplastic lesion prevalence. Tests of significance included pairwise comparisons of each dosed group with controls and a test for an overall dose-related trend. Continuity-corrected tests were used in the analysis of lesion incidence, and reported P values are one sided.
Analysis of Continuous Variables: Organ and body weight data, which historically have approximately normal distributions, were analyzed with the parametric multiple comparison procedures of Dunnett (1955) and Williams (1971, 1972). Jonckheere's test (Jonckheere, 1954) was used to assess the significance of the dose-related trends. Average severity values were analyzed for significance with the Mann-Whitney U test. Treatment effects were investigated by applying a multivariate analysis of variance (Morrison, 1976) to the transformed data to test for simultaneous equality of measurements across dose levels.

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Dermal irritation:
effects observed, treatment-related
Mortality:
mortality observed, treatment-related
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
not examined
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
effects observed, treatment-related
Details on results:
CLINICAL SIGNS AND MORTALITY: Survival rates of dosed male and female rats were similar to those of the vehicle controls. The only clinical finding attributed to dosing was irritation of the skin at the site of application in 100 mg/kg bw/d females.


BODY WEIGHT AND WEIGHT GAIN: The mean body weights of dosed male and female rats were similar to those of the vehicle controls throughout the study.


HISTOPATHOLOGY:
Skin: No neoplasms of the skin were attributed to treatment with test material. Incidences of squamous cell papilloma, keratoacanthoma, trichoepithelioma, basal cell adenoma, or carcinoma (combined) were significantly decreased in 100 mg/kg bw/d male rats. Incidences of epidermal hyperplasia, sebaceous gland hyperplasia, parakeratosis, and hyperkeratosis in all dosed groups were significantly greater than those in the vehicle control groups. The severities of these lesions generally increased with increasing dose and ranged from minimal to mild. Females in the 100 mg/kg bw/d group had a significantly greater incidence of ulceration at the site of application than did the vehicle controls.

Kidney: Incidences of renal tubule hyperplasia in dosed females were significantly greater than those of the vehicle controls, and the incidence of renal tubule adenoma in 50 mg/kg bw/d males was marginally increased. Incidences of chronic nephropathy were similar between vehicle control and dosed groups of male and female rats; however, the severity of nephropathy increased with increasing dose in female rats. The incidences of renal tubule adenoma in all groups of males and of renal tubule carcinoma in 50 mg/kg bw/d females exceeded the historical control ranges. An extended evaluation of the kidney revealed additional renal tubule adenomas in vehicle control and dosed males, and renal tubule adenomas and/or carcinomas in dosed females. When the single and step sections were combined, the incidences of renal tubule hyperplasia in dosed females and of renal tubule adenoma or carcinoma (combined) in 50 mg/kg bw/d females were significantly greater than those of the controls. In female rats, the combined single and step section evaluations of the kidney revealed a significant dose- related increase in the incidence of renal tubule hyperplasia and two adenomas and two carcinomas in the 50 mg/kg bw/d group but only one neoplasm (an adenoma), in the 100 mg/kg group. Renal tubule neoplasms are uncommon in female F344/N rats, and the presence of four neoplasms in the 50 mg/kg bw/d group, combined with the increased incidence of hyperplasia, is suggestive of an association with chemical exposure. However, the absence of an increase in neoplasms in the 100 mg/kg bw/d group in the presence of increased hyperplasia makes the association with chemical exposure uncertain.

Forestomach: The incidences of chronic active inflammation (vehicle control, 1/50; 50 mg/kg bw, 3/50; 100 mg/kg bw, 10/50), epithelial hyperplasia (2/50, 5/50, 13/50), and epithelial ulcer (1/50, 3/50, 11/50) were significantly increased in the forestomach of 100 mg/kg bw females. The severities of these lesions were similar among all groups.

Pancreas: The incidence of pancreatic acinar atrophy in 100 mg/kg male rats was significantly greater than that in the vehicle controls.

Effect levels

open allclose all
Dose descriptor:
NOAEL
Remarks:
(systemic effects)
Effect level:
50 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: pancreatic acinar atrophy and nephropathy at the higher dose
Dose descriptor:
LOAEL
Remarks:
(local effects)
Effect level:
50 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: based on non-neoplastic lesions of the skin at all doses

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

All dose formulations analysed during the 2 year studies were within 10% of the target concentration.

Applicant's summary and conclusion

Conclusions:
Under the test conditions, there was no evidence of carcinogenic activity of the test substance in male rats in any of the tested dose levels. There was an equivocal evidence of carcinogenic activity in female rats based on a marginal increase in the incidences of renal tubule neoplasms. However, the absence of an increase in neoplasms in the 100 mg/kg bw/d group in the presence of increased hyperplasia makes the association with chemical exposure uncertain.
Executive summary:

A two-year dermal study was conducted in F344/N rats to evaluate the carcinogenic potential of 'amides, C8-18 (even-numbered) and C18-unsatd., N,N-bis(hydroxyethyl)' (in the form ofcoconut oil acid diethanolamine condensate).

 

 Doses studied include 0, 50, or 100 mg/kg bw/d test substance (0, 85, or 170 mg/mL in ethanol). 50 male/female test animals were used in each group. 5 exposures per week were given for 104 wk. The animals were observed twice daily, body weights and clinical findings were recorded periodically. Necropsy was performed on all animals and complete histopathology was performed.

 

The survival rates of treated male and female rats were similar to those of the vehicle controls. The mean body weights of dosed males and females were similar to those of the vehicle controls throughout the study. The only chemical-related clinical finding was irritation of the skin at the site of application in 100 mg/kg bw/d females. There were marginal increases in the incidences of renal tubule adenoma or carcinoma (combined) in 50 mg/kg bw/d females. The severity of nephropathy increased with increasing dose in female rats.

 

 Non neoplastic lesions of the skin at the site of application included epidermal hyperplasia, sebaceous gland hyperplasia, parakeratosis, and hyperkeratosis, and the incidences and severities of these lesions increased with increasing dose. The incidences of chronic active inflammation, epithelial hyperplasia, and epithelial ulcer of the forestomach increased with dose in female rats, and the increases were significant in the 100 mg/kg bw/d group.

 

 Under the test conditions, there was no evidence of carcinogenic activity of the test substance in male rats administered 50 or 100 mg/kg bw/d. There was an equivocal evidence of carcinogenic activity in female rats based on a marginal increase in the incidences of renal tubule neoplasms. However, the absence of an increase in neoplasms in the 100 mg/kg bw/d group in the presence of increased hyperplasia makes the association with chemical exposure uncertain.