(hydroxyethyl)urea

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2006-11-03 to 2008-08-25

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline complient study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Deviations:

yes

Remarks:

seven types of deviations were identified, however there were no effects on the study

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Hydrovance®

IUPAC Name:

Hydrovance®

Constituent 2

Reference substance name:

Hydroxyethyl Urea

IUPAC Name:

Hydroxyethyl Urea

Details on test material:

- Name of test material (as cited in study report): Hydrovance® Moisturizing Agent
- Physical state: viscous, clear liquid

For the first and second exposures:
- Analytical purity: 49.5 % of solids
- Lot/batch No.: 90604357
- Expiration date of the lot/batch: 2007-03-12

For the third exposure:
- Analytical purity: 50.2 % of solids
- Lot/batch No.: 90738271
- Expiration date of the lot/batch: 2008-06-26

- Storage condition of test material: at room temperature

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories (Wilmington, MA)
- Age at study initiation:
50 days old for the Exposure 1
49 to 56 days old for the Exposure 2
54 days old for the Exposure 3
- Weight at study initiation:
183 to 190 g (males) and 154 to 177 g (females) for the Exposure 1
204 to 223 g (males) and 172 to 190 g (females) for the Exposure 2
209 to 220 g (males) and 198 to 209 g (females) for the Exposure 3
- Fasting period before study: no
- Housing: two per cage in metal cages in a housing chamber
- Diet (e.g. ad libitum): Certified Purina Rodent Chow 5002 (PMI Nutrition International, LLC, Brentwood, MO) ad libitum, except during the exposure period
- Water (e.g. ad libitum): City ofChicago tap water, via automatic water system, ad libitum, except during the exposure period
- Acclimation period: 2 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C):
from 19.3 to 23.9 (for the Exposure 1)
from 19.8 to 24.4 (for the Exposure 2)
from 19.0 to 22.2 (for the Exposure 3)
- Humidity (%):
from 15.2 to 60.0 (for the Exposure 1)
from 25.1 to 51.7 (for the Exposure 2)
from 38.0 to 67.9 (for the Exposure 3)
- Air changes (per hr): 12 to 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

other: ASTM Type 1 water (1:1 dilution) only for the Exposure 2

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus:
Exposure 1 and Exposure 2: 64-port nose only systems
Exposure 3: Cannon stainless sreel 52-port nose-only inhalation cliamber (Lab Products Inc, Seaford, DE)
- Method of holding animals in test chamber: nos-only inhalation holders
- System of generating particulates/aerosols:
Exposure 1: one-jet Laskin nebulizer (IITRI built)
Exposure 2: one-jet Laskin nebulizer and one Aerogen (Aeroneb) nebulizer (Aerogen Ireland Ltd, Galway, Ireland)
Exposure 3: compressed air-operated Laskin nebulizer positioned in a three-neck round bottom flask
- Method of particle size determination: Quartz Crystal Microbalance cascade impactor (Model PC-2, California Measurements Inc, Sierra Madre, CA)
- Treatment of exhaust air: by HEPA filtration prior to being discharged into the outside atmosphere

TEST ATMOSPHERE
- Brief description of analytical method used: Samples from the first and third exposures were collected on pre-weighed filters. After sampling, the filters were weighed again to determine the weight oftest substance collected. A dry gas meter connected to the vacuum punlp was used to measure the corresponding total volume of chamber air sampled and the weight to volume ratio was determined in order calculated the aerosol mass concentration.
Samples from the second exposure were collected on filters that were first desiccated on a plastic Petri dish in a bell jar. In order to calculate the actual test substance concentration in the second exposure, the dried filters were weighed (pre-sampling weight); the samlple collected, and the wet filters were again weighed (wet value) before being desiccated again in the Petri dishes to obtain the dry weight. The Hydrovance® concentration was the total desiccated dry weight of the filter minus the pre-sampling weight multiplied by four.
- Samples taken from breathing zone: yes

TEST ATMOSPHERE (if not tabulated)
Exposure 1:
- Particle size distribution: 0.83-1.28 µm
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): 1.06 µm / 1.80

Exposure 2:
- Particle size distribution: 0.66-3.10 µm
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): 1.63 µm / 2.33

Exposure 3:
- Particle size distribution: 1.30-2.75 µm
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): 1.90 µm / 2.87

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: ≥2mg/L, or the highest attainable concentration if less than 2 mg/L, for 4 hours + T (90), the time required to reach 90 % of the target concentration (as determined during the test atmosphere development phase)

Analytical verification of test atmosphere concentrations:

yes

Remarks:

Air containing aerosols collected on pre-weighed filters; collected amount of substance related to volume of air streaming into exposure chamber during sampling period to determine aerosol mass concentration in test air

Duration of exposure:

4.05 h

Remarks on duration:

The rats were exposed four 4 hours plus three minutes (time to reach 90 % concentration, T90)

Concentrations:

Exposure 1: 0.59 mg/L
Exposure 2: 5.152 mg/L
Exposure 3: 0.125 mg/L

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 15 days
- Frequency of observations and weighing: the animals were observed for signs of toxicity during exposure (to the extent possible), immediately after the first exposure (within eight minutes), second exposure (within three minutes) and third exposure (within one to six minutes), and at least once daily during a 15-day observation period (including the exposure day). Body weights were determined on the day after animal receipt, prior to randomisation, on Day 1 (prior to exposure), and weekly thereafter. All animals were weighed on the day of necropsy prior to euthanasia.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, histopathology.

Statistics:

Descriptive statistics (mean and standard deviation) were calculated for the inhalation exposure data and body weights.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.152 mg/L air (analytical)

Based on:

act. ingr.

Exp. duration:

4.05 h

Mortality:

No rats died during the study.

Clinical signs:

other: Eight minutes following the first exposure, five male and four female animals had wet inguinal fur and two females had redness around nose. At approximately four hours post exposure, all animals were normal and remained so until necropsy. Three minutes fo

Body weight:

All exposed rats gained weight during the study.

Gross pathology:

After the first exposure, gross lesions noted at necropsy included lungs with foci in three females. Gross lesions noted at necropsy after the second exposure included foci on the lungs of four males and one female, a white lesion on the small intestine in one male, and a white opaque lesion on the left kidney in one female. After the third exposure, gross lesions noted at necropsy included lungs with foci in two males. Histopathologic evaluation of the lungs from two animals from the third exposure having lung foci showed no hemosiderophages in the lymph node of either animal. This supports a Iack of subacute to chronic hemorrhage in the pulmonary parenchyma of both animals. Since small foci of peracute hemorrhage in the lungs are not rare in rodents, the lung foci found in animals from this study were not considered related to treatment with the test substance.

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Based on the results of this study, the acute inhalation median lethal concentration (LC50) of the solid fraction of Hydrovance® Moisturing Agent in male and female rats is greater than 5.152 mg/L, the highest test atmosphere concentration attainable for this test substance.

Executive summary:

The test substance, Hydrovance® Moisturizing Agent, was tested as aerosols for acute inhalation toxicity in rats and observing its effects on five male and five female rats following nose-only inhalation exposure. The rats were exposed for four hours plus three minutes (time to reach 90% concentration, T90). The test atmosphere was generated by aerosolising the neat or diluted test substance with a one jet Laskin nebulizer. Following exposure, the rats were observed daily for adverse clinical signs and weighed weekly. All rats were euthanised and subjected to a gross necropsy following the 15-day (including exposure day) observation period. Three exposures were conducted: Exposures 1 and 3 used the Hydrovance® Moisturizing Agent as supplied, and Exposure 2 used Hydrovance® diluted (1:1) with ASTM type 1 water. The nominal concentration of non-volatiles in the test substance is 50%. The test concentrations which were measured gravimetrically using filter-collected aerosol samples during the exposure are indicative of the non-volatile portion of the test substance only. The test substance concentrations were calculated using the appropriate non-volatile fraction present in the formulation (50% for Exposures 1 and 3, and 25% for Exposure 2). For Exposure 1, the mean aerosol mass concentration was 0.59 mg/L. No animals died during the exposure or observation period. All animals gained weight. Gross lesions noted at necropsy included lungs with foci in three females. For Exposure 2, the mean aerosol mass concentration was 5.152 mg/L. No mortality occurred during the exposure or observation periods. Salivation was observed in two females and one male after exposure to the test substance. All animals gained weight during the observation period. Gross lesions noted at necropsy included lungs with foci on four males and one female, one male with a lesion on the small intestine, and one female with a white opaque lesion on the left kidney. Exposure 3 had a mean aerosol mass concentration of 0.125 mg/L. No animals died during the exposure or observation period. All animals gained weight. The clinical observations included red material around the nose (three males and four females), red material around the eyes (one male and one female) and alopecia (one male). Gross lesions noted at necropsy included lungs with foci in two males. Histopathologic evaluation of the lungs from two animals from the third exposure group having lung foci showed no hemosiderophages in the lymph node of either animal. This supports a lack of subacute to chronic hemorrhage in the pulmonary parenchyma of both animals. Since small foci of peracute hemorrhage in the lung are not rare in rodents, the lung foci found in animals from this study were not considered related to treatment with the test substance. Based on the results of this study, the acute inhalation median lethal concentration (LC50) of the solid fraction of Hydrovance in male and female rats is greater than 5.152 mg/L, the maximum concentration attained in this study. Based on the typical composition of Hydrovance which is 80% of the solids is hydroxyethyl urea, this correspods to ca. >4 mg/l of hydroxyethyl urea. Based on this and the lack of adverse effects hydroxyethyl urea is not classified for GHS.