2-[2-(dimethylamino)ethoxy]ethanol

Repeated dose toxicity: dermal

Administrative data

Endpoint:

short-term repeated dose toxicity: dermal

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1986-06-03 to 1987-05-14

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study equivalent to OECD 410, except that a no-effect dose was not tested and the study lasted 11 days instead of the 21/28 in the method.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

No-effect low dose not used; study lasted only 11 days instead of 21/28.

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Constituent 2

Reference substance name:

2-[2-(dimethylamino)ethoxy]ethanol

EC Number:

216-940-1

EC Name:

2-[2-(dimethylamino)ethoxy]ethanol

Cas Number:

1704-62-7

Molecular formula:

C6H15NO2

IUPAC Name:

2-[2-(dimethylamino)ethoxy]ethan-1-ol

Details on test material:

- Name of test material (as cited in study report): 2-[2-(dimethylamino)-ethoxy]ethanol (DMEE)
- Substance type: Pure active substance
- Physical state: Amber, non-viscous liquid
- Analytical purity: 97.7%
- Storage condition of test material: Stored at room temperature

Test animals

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hazleton Dutchland, Denver, PA
- Age at study initiation: 12-13 wks when received, 14-15 wks of age at first dose
- Weight at study initiation: Between 2 and 3 kg
- Fasting period before study: None
- Housing: Housed individually in stainless steel cages with wire floors
- Diet (e.g. ad libitum): Agway Prolab Certified Rabbit Diet (Agway, Inc:, St. Mary's, OH), 4 oz of food/d/rabbit during acclimation and gradually increased to 7 oz/day. After treatment was initiated, food was available ad libitum.
- Water (e.g. ad libitum): Water (Municipal Authority of Westmoreland County, Greensburg, PA) was administered by an automatic watering
system with demand control valves mounted on each rack,
- Acclimation period: 2 wks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25 deg C
- Humidity (%):40 - 70%
- Air changes (per hr): N/A
- Photoperiod (hrs dark / hrs light): 12 h dark/light cycle each day

IN-LIFE DATES: From: 1986-06-16 To: 1986-06-27

Administration / exposure

Type of coverage:

occlusive

Vehicle:

water

Details on exposure:

TEST SITE
- Area of exposure: Dorsal area of the trunk
- % coverage: Not less tnan 10% of the body surface area was cleared for the application of the test substance.
- Type of wrap if used: A double layer of gauze sheeting was wrapped around the trunk and secured with adhesive tape. The dose was then
applied through the gauze dressing and polyethylene sheeting was then wrapped around the trunk over the gauze. Plastic ties were added to the ends of the wrap to secure the polyethylene sheeting. To protect this sheeting from removal or tearing, the trunk of the rabbit was wrapped with Vetrap Bandaging Tape. The ends of the Vetrap were secured with adhesive tape.
- Time intervals for shavings or clipplings: Prior to the first dose, time interval not specified after the first dose.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Yes, the wrapping was removed and the back of each animal was wiped with a damp cloth.
- Time after start of exposure: At least six hours of exposure.

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0, 50, 250 or 500 mg/kg body weight/day (0, 0.1, 0.5, or 1.0 mL/kg body weight/day)
- Concentration (if solution): 50%
- Constant volume or concentration used: yes
- For solids, paste formed: N/A

VEHICLE
- Justification for use and choice of vehicle (if other than water): N/A; water was used.
- Amount(s) applied (volume or weight with unit): N/A
- Concentration (if solution): N/A
- Lot/batch no. (if required): N/A
- Purity: N/A

USE OF RESTRAINERS FOR PREVENTING INGESTION: None needed; application was well wrapped with double sheeting.

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

N/A

Duration of treatment / exposure:

6 h/day over an 11 d period (total of 9 applications)

Frequency of treatment:

Daily from Monday through Friday

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

50 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

250 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

500 mg/kg bw/day (nominal)

No. of animals per sex per dose:

5/sex/group

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Doses for the study were selected based on the results of preliminary testing of test substance in a probe study conducted at BRRC. The procedures and results of the probe study, which did not follow a specific protocol (according to the author) are included in Appedix 9 of the study report (not provided for review).
- Rationale for animal assignment (if not random): N/A
- Rationale for selecting satellite groups: N/A
- Post-exposure recovery period in satellite groups: N/A
- Section schedule rationale (if not random): N/A

Positive control:

N/A

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily
- Cage side observations checked: Signs of irritation.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily for signs of toxicity, with particular attention being paid to the treated area of skin.

DERMAL IRRITATION (if dermal study): Yes
- Time schedule for examinations: Careful examination was made prior to dosing each day for signs of irritation.

BODY WEIGHT: Yes
- Time schedule for examinations: Body weights were measured immediately prior to the first dose, prior to the fifth dose, one week after the first dose, and prior to sacrifice.

FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes, collected for all animals on days 2, 4, 6, 7, 9, and 11.

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data

WATER CONSUMPTION: No data
- Time schedule for examinations: N/A

OPHTHALMOSCOPIC EXAMINATION: No data
- Time schedule for examinations: N/A
- Dose groups that were examined: N/A

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Prior to sacrifice.
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: All animals
- Parameters checked: Erythrocyte count, mean corpuscular hemoglobin concentration (MCHC), hemoglobin, hematocrit, total leukocyte count, mean corpuscular volume (MCV), platelet count, mean corpuscular hemoglobin (MCH ), and differential leukocyte count.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Prior to sacrifice.
- Animals fasted: No data
- How many animals: All animals
- Parameters checked: Creatinine, glucose, total bilirubin, direct bilirubin, total protein, albumin, globulin, calcium, phosphorus, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, sorbitol dehydrogenase, sodium, potassium, chloride, and urea nitrogen.

URINALYSIS: No data
- Time schedule for collection of urine: N/A
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data
- Parameters checked: N/A

NEUROBEHAVIOURAL EXAMINATION: No
- Time schedule for examinations: N/A
- Dose groups that were examined: N/A
- Battery of functions tested: sensory activity / grip strength / motor activity / other: N/A

OTHER: N/A

Sacrifice and pathology:

GROSS PATHOLOGY: Yes; The liver, kidneys, adrenals, brain, and heart of all rabbits and the testes of all males were weighed at the time of necropsy.
HISTOPATHOLOGY: Yes; the indicated tissues were fixed in 10% neutral buffered formalin and saved for examination. Histologic examinations were performed for rabbits of the water control and high dose groups, including: all lesions, brain, pituitary, thymus, thyroid (with parathyroid), adrenals, liver, kidneys, testes and epididymis (males), uterus and ovaries (females), spleen, mesenteric lymph nodes, sternum with marrow, and treated and untreated skin. The treated and untreated skin from animals in the mid and low dose groups were also examined histologically. Other tissues fixed in 10% neutral bufferend formalin but not examined include: spinal cord, sciatic nerve, eyes, salivary gland, aorta, trachea, lungs with mainstem bronchi, esophagus, stomach, small and large intestine, pancreas, gallbladder, prostate, accessory sex glands, mammary gland, urinary bladder, mediastinal lymph nodes and gastrocnemius muscle.

Other examinations:

N/A

Statistics:

Food consumption, body weight, and organ weight data were intercompared for the dose and control groups by use of Levene's test for homogeneity of variances, by analysis of variance, and by pooled variance t-tests. The t-tests were used, if the analysis of variance was significant, to delineate which groups differed from the control group. If Levene's test indicated heterogeneous variances, the groups were compared by an analysis of variance for unequal variances followed, if necessary, by separate variance t-tests. Non-parametric data were analyzed by the Kruskal-Wallis test or by the Wilcoxon rank sum test as modified by Mann-Whitney. Frequency data were compared to Fisher's exact tests where appropriate. All statistical tests, except the frequency comparisons were performed using BMDP Statistical Software. The fiducial limit of 0.05 was used as the critical level of significance for all tests.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

One death, cause not determined.

Dermal irritation:

effects observed, treatment-related

Description (incidence and severity):

See results below.

Mortality:

mortality observed, treatment-related

Description (incidence):

One death, cause not determined.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

(no treatment-related effects)

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:

effects observed, treatment-related

Description (incidence and severity):

See results below.

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

See results below.

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

See results below.

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

See results below.

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY
One male animal from the high dose group died on Day 6 of the study. No specific cause of death was determinable for this animal.

DERMAL IRRITATION
Erythema and edema ranging from mild to severe were observed in all animals from all treatment groups. Necrosis of the epidermis was also observed in all treated animals. These lesions were generally more severe and extensive as the dosage was increased with the necrosis being only mild and focal in the low dose group. Fissuring of the skin at the dose site was also observed in most of the males and females treated with the test substance. Occurrences of exfoliation, excoriation, and ecchymosis were also observed in several animal.

BODY WEIGHT AND WEIGHT GAIN
N/A

FOOD CONSUMPTION
N/A

FOOD EFFICIENCY
N/A

WATER CONSUMPTION
N/A

OPHTHALMOSCOPIC EXAMINATION
N/A

HAEMATOLOGY
Increases in segmented heterophils were observed in the high dose group for both sexes. Total leukocyte count was elevated in females from the high dose group, and a dose-related increase in platelets was observed in males from all treatment groups. Statistically significant decreases in hemoglobin and hematocrit values observed in males from the high dose group may have indicated early alterations in erythrocytes that could progress with additional treatment.

CLINICAL CHEMISTRY
N/A

URINALYSIS
N/A

NEUROBEHAVIOUR
N/A

ORGAN WEIGHTS
A statistically significant reduction in absolute adrenal weight was observed in the males from the high dose group. The adrenal weight relative to body weight and relative to brain weight were also reduced from the control value although the differences were not statistically significant. Statistically significant increases in liver weight relative to body weight were observed for males of the high and mid dose groups. This resulted from slightly elevated absolute liver weights and slightly depressed body weights for these groups. No effects on any absolute or relative organ weights were observed for females.

GROSS PATHOLOGY
Treatment-related gross necropsy findings were limited to the skin of the treatment area. These findings included crusting or scaling dermatitis and epidermitis described as excoriation and encrustation.

HISTOPATHOLOGY: NON-NEOPLASTIC
Histologic alterations related to treatment with DMEE were also restricted to the treated skin. The treated skin from all animals from the high and intermediate dose groups and 2 of the 5 animals in the low dose group was diagnosed to have necrotizing dermatitis with severity corresponding to the dose level. The remaining animals in the low dose group had treated skins characterized by either dermatitis or ulcerative dermatitis. Areas of acanthosis were also observed in the treated skin of animals from the low and mid dose groups. This finding was not evident in the high dose group due to complete necrosis of the epidermis.

HISTOPATHOLOGY: NEOPLASTIC (if applicable)
N/A

HISTORICAL CONTROL DATA (if applicable)
N/A

OTHER FINDINGS
N/A

Effect levels

Dose descriptor:

LOEL

Effect level:

<= 50 other: mg/kg bw/day (nominal; lowest dose tested)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

dermal irritation

histopathology: non-neoplastic

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Based on the results of this study, the test substance was considered to be a severe skin irritant at doses of 50 mg/kg/day and above in male and female rabbits.