2-(2-aminoethylamino)ethanol

Repeated dose toxicity: dermal

Administrative data

Endpoint:

short-term repeated dose toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Abstract. Original report not yet available.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)

Deviations:

not applicable

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-(2-aminoethylamino)ethanol

EC Number:

203-867-5

EC Name:

2-(2-aminoethylamino)ethanol

Cas Number:

111-41-1

Molecular formula:

C4H12N2O

IUPAC Name:

2-[(2-aminoethyl)amino]ethan-1-ol

Details on test material:

- Name of test material: aminoethylethanolamine (AEEA)
- Analytical purity: 99.9 %
- Lot: TB-890105
- Obtained from : Chemicals & Metals Department, The Dow Chemical Company (Freeport, TX)
- Physical State: colortess liquid
- Odor: slightly ammoniacal

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 rats (approximately five to six weeks of age) purchased from Charles River Laboratories, Inc. Kingston, NY were used in the study. Upon arrival at the laboratory rats were examined by the laboratory veterinarian and acclimated to the laboratory environment according to the SOP of the Subchronic/Chronic Toxicity Section for 16 days. During acclimation, rats were assigned one/cage to test groups using a computergenerated randomization scheme based on body weights. Identification was accomplished by inserting a unique alphanumeric metal tag in one ear of each rat. The animal rooms of the testing facility were designed to maintain adequate environmental conditions (temperature, humidity, and photocycle) for the species used. Tap water and Purina Certified Rodent Chow #5002 (Purina Mills, Inc., St. Louis, MO) were available ad libitum during the pre-study and
study periods. The feed was analyzed by Purina Mills, Inc. and found to be nutritionally adequate and to be free of significant levels of spedfic contaminants. Drinking water was analyzed as outlined in the SOP of The Toxicology Research Laboratory and was also round to be of acceptable quality and free of significant levels of specific contaminants.
All animals were weighed just prior to the initiation of dosing and approximately weekly thereafter. All in-life weights were collected using an in-house Computer system. Feed consumption data was also obtained at approximately weekly intervals.

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

other: distilled water

Details on exposure:

Route of Administration: dermal

TEST SITE
- Area of exposure: 5 x 5 cm on the back, representing at least 10 % of the surface area of the animal
- coverage: 100 %
- Type of wrap: absorbent gauze patch which was helt in place with an elastic with wrap which was secured with elastic tape
- Time intervals for shavings or clipplings: prior to study initiation and as needed


REMOVAL OF TEST SUBSTANCE
- Washing: wraps were removed approx. six hours after application and the test site was wiped with a water-dampened disposable
towel to remove any residual test material
- Time after start of exposure: 6 hours

TEST MATERIAL
- Amount applied: 4 ml/kg bw
- Concentration: 2.5, 7.5 or 25 % solution (w/v) at 4 ml/kg bw for rats receiving 100, 300 or 1000 mg/kg bw/day

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The stability of AEEA in distilled water and the potential of the mixing method to produce a homogeneous dosing Solution were verified analyticaUy. In
addition, the concentrations of AEEA in a set of dose solutions were also quantitated analytically during the study.

Duration of treatment / exposure:

4 weeks

Frequency of treatment:

6 hours/day, 5 days/week

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 100, 300 or 1000 mg/kg bw/day
Basis:
nominal per unit body weight

No. of animals per sex per dose:

5 rats

Control animals:

yes, concurrent vehicle

Details on study design:

In a probe study, two male rats received 1000 mg/kg bw/day as a 25 % solution in distilled deionized water for 6 hours/day for 4 days.



The 4 ml/kg bw dosing volume required to administer the test material represented the maximum volume which could be maintained at the application site.

Examinations

Observations and examinations performed and frequency:

Observations and Records

A careful clinical examination was conducted on all animals prior to the start of the study and approximately weekly thereafter.
This examination included thorough evaluations ofthe skin, für, mucous membranes, respiration, circulatory system function, autonomic and central
nervous system function (e.g., tremors, convulsions) and behavior pattern.
An additional observation for morbidity, mortality and the availability of feed and water was made each day of the work-week and twice daily on weekends and holidays.

Evaluation of derrnal application site
The condition of the test material application site was subjectively evaluated when wraps were removed on the last day of dosing each week and on theday prior to necropsy. A modification of the acute dermal irritation scoririg system recommended by the OECD (1981b) was utilized:

Erythema abd eschar:

Within normal limits: 0
Very slight erythema (barely perceptible): 1
Well-defined erythema: 2
Moderate to severe erythema: 3
Severe erythema to slight eschar formation: 4

Edema:

Within normal limits: 0
Very slight (barely perceptible): 1
Well-defined (edges raised) : 2
Moderate (raised approximately 1 millimeter): 3
Severe (raised more than 1 millimeter: 4

Scaling and fissuring:

Within normal limits: 0
Slight scaling: 1
Moderate - severe scaling: 2
Slight fissuring: 3
Moderate - severe fissuring: 4


In addition, necrosis, scabs and/or scars were noted if present; however, they were not graded


Clinical Pathology:

Hematology:
Blood samples were collected from all surviving animals via orbital sinus puncture following anethesia with methoxyflurane and just prior to necropsy. The following hematologic parameters were evaluated for each animal:
hematocrit (HCT), hemoglobin (HGB), erythrocyte count (RBC), total leukocyte count (WBC), and platelet counts (PLAT). Blood smears were prepared and stained with Wright's stain for all animals from which blood samples were collected. Complete blood smear examinations were conducted which included differential leukocyte counts (the number of leukocytes counted were specified if other than 100 cells were counted) and an assessment of erythrocyte, leukocyte and platelet morphology. Any morphologic abnormalities observed were reported.

Clinical Chemistry
Blood samples were collected from all surviving animals via orbital sinus puncture following anethesia with methoxyflurane and just prior to necropsy. The following parameters were evaluated for each animal:
alkaline phosphatase activity (AP), alanine aminotransferase activity (ALT), aspartate aminotransferase activity (AST), total protein (TP), albumin (ALB),
globulin (GLOB) (calculated), total bilirubin (TBILI), glucose (GLUC), urea nitrogen (UN), creatinine (CREAT), phosphorus (PHOS), caldum (CALC), sodium (NA), potassium (K) and chloride (CL).

Pathology.
All surviving rats were fasted overnight and presented for necropsy approximatdy 24 hours after the final administration of test material. Rats were weighed, anesthetized with methoxyflurane and humanely euthanatized. All animals were examined for gross pathological changes by a veterinary pathologist. The necropsy included examination of the eyes by visual inspection of the cornea, lens and other internal components via placement of a moistened glass slide on the corneal surface. Weights of the brain, heart, liver, kidneys, adrenals and testes were recorded for each animal. Lungs were distended to an approximately normal inspiratory volume with neutral, phosphate-buffered 10 % formalin solution by tracheal instillation using a hand-operated syringe. The nasal cavity was flushed by a similar method via the pharyngeal duct. Representative samples of tissues and any masses or lesions were preserved in formalin. Special attention was given to the skin at the site of application of the test material. Samples of skin from the clpped site where the test material was applied and from an unshaven and untreated site just caudal to this were excised and preserved. Both areas were covered by the wrappings used to maintain the test material at the application site. Thus, the untreated skin served as a control for the possible confounding effects of mechanical irritation of the skin by the wrapping materials, A third skin sample was also collected from the abdomen to include mammary gland tissue; however, this was not used for comparative purposes. Tissues were prepared for light microscopic evaluation by standard procedures sectioned at approximately 6 um and stained with hematoxylin and eosin. Samples of skin obtained from the application site and the adjacent, untreated site, liver, kidneys and any masses and lesions were examined from all control and high dose group animals. Treated and untreated skin from all intermediate dose group animals and all grossly observed lesions were also examined histologically.

Other examinations:

For the probe study, animals were observed for any signs of systemic or dermal treatment-related effects over the dosing period.

Statistics:

In-life body weights were evaluated using a three-way repeated measures analysis of variance (ANOVA) for time, sex and dose. In the three-way repeated measures ANOVA, differences between groups were primarily detected by the time-dose interaction. Terminal body weight, organ weight (absolute and relative, excluding testes), hematologic parameters (excluding differential WBC counts), clinical chemistry parameters, and urine specific gravity were evaluated using a two-way ANOVA with the factors of sex and dose; differences between groups were primarily detected by the dose factor. Results for testes weight(absolute and relative) were analyzed using a one-way ANOVA. A Bonferroni correction was used to compensate for the multiple comparisons with the control group. Final interpretation of numerical data considered statistical analyses along with other factors, such as dose-response relationships and whether the results were plausible in light of other biological and pathological findings.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Dermal irritation:

effects observed, treatment-related

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

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:

not examined

Details on results:

CLINICAL SIGNS AND DERMAL IRRITATION:
Evaluation of the skin at the application site revealed a minimal degree of erythema in a single high dose female and scabbing in 3/5 male and 3/5 femal rats administered 1000 mg/kg bw/day on day 30 of the dosing period.

GROSS PATHOLOGY:
Treatment-related gross pathologic observations were limited to the skin at the site of test material application.
Dermal crusts were observed in 3 of 5 males and 3 of 5 females administered 1000 mg/kg bw/day AEEA.
No gross lesions were observed in the application site skin of any other treatment or control group.

HISTOPATHOLOGY:
There were no treatment-related histopathologic changes indicative of systemic toxicity observed in rats administered AEEA. Coagulative necrosis and inflammation of hepatic tissue was noted in superficial areas of the caudal lobe of the livers of a high dose group male and female; however these changes were consistent with localized anoxia secondary to compression of the tissue during the wrapping process. Tissues in the remaining lobes of the liver of these animals were normal. Histopathologic examination of the skin at the application site revealed ulcers, accompanied by inflammation of the dermis and epidermis of several male and female rats administered 1000 mg/kg bw/day AEEA.

The separation of epidermal cells (epidermal vacuolation), interpreted to be a precursor of ulcer formation, was also observed in a single high dose group male and female rat. In addition a minimal degree of epidermal hyperplasia was observed in application site skin and untreated skin from contro and treatment groups of rats alike. This change, consisting in most cases of a 1-2 cell increase in epidermal thickness, was primarily attributed to mechanical irritation of the skin from wrapping materials and/or clipping. However, the incidence of a more pronounced degree of hyperplasia, consisting of increases of 2-4 cells over a larger area, was higher in rats administered 1000 mg/kg bw/day AEEA than in controls.

Effect levels

Dose descriptor:

NOAEL

Effect level:

1 000 other: mg/kg bw / day

Sex:

male/female

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

In the 4-day dermal probe, there was no evidence of dermal or systemic toxicity.

Applicant's summary and conclusion

Executive summary:

In a 4 -day dermal probe when two rats received 1000 mg/kg bw/day there was no evidence of dermal or systemic toxicity.

In a subacute toxicity study AEEA (99,9 % a.i.) was administered to five Fisher 344 rats per sex per dose by dermal application 6 hours/day, 5 day/week for a period of approximately 4 weeks at dose levels of 0, 100, 300 or 1000 mg kg bw/day.

There were no treatment-related effects observed in mortality, clinical appearance, behavior, in-life body weight, food consumption, hematology or clinical chemistry of male or female rats administered AEEA relative to controls. Treatment-related gross pathologic observations were limited to the skin at the site of test material application. There were no treatment-related histopathologic changes indicative of systemic toxicity observed in rats administered AEEA.

The NOAEL was considered to be 1000 mg/kg bw/day for both males and females.