1-(N,N-bis(2-hydroxyethyl)amino)propan-2-ol

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 Jan to 4 March 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD guideline study to GLP, with minor deviations which are not expected to affect the outcome

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Deviations:

yes

Remarks:

Animals stratified by body weights before being randomly assigned to treatment groups.

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))

Deviations:

yes

Remarks:

Animals stratified by body weights before being randomly assigned to treatment groups.

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1-(N,N-bis(2-hydroxyethyl)amino)propan-2-ol

EC Number:

229-764-5

EC Name:

1-(N,N-bis(2-hydroxyethyl)amino)propan-2-ol

Cas Number:

6712-98-7

Molecular formula:

C7H17NO3

IUPAC Name:

1-[bis(2-hydroxyethyl)amino]propan-2-ol

Test material form:

other: Liquid, clear white

Details on test material:

- Name of test material (as cited in study report): Diethanolisopropanolamine (DEIPA
- Substance type: Technical product
- Physical state: Liquid
- Analytical purity: 93%
- Impurities (identity and concentrations): No data
- Composition of test material, percentage of components: No data
- Isomers composition: No data
- Purity test date: Not specified
- Lot/batch No.: 980035B
- Expiration date of the lot/batch: Not specified
- Stability under test conditions: Stable for at least 10 days in water
- Storage condition of test material: Not specified

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories Inc. (Raleigh, NC)
- Age at study initiation: 7 weeks
- Weight at study initiation: Not specified
- Fasting period before study: Not specified
- Housing: Individually caged in sainless steel cages with wire mesh floors suspended above catch pans.
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25
- Humidity (%): 40-70
- Air changes (per hr): 12-15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
Aqueous solution mixed prior to start of study and weekly thereafter.

VEHICLE
- Concentration in vehicle: 0, 7.5, 25, 250 mg/ml
- Amount of vehicle (if gavage): 4 ml/kg
- Purity: Not specified

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Dose samples diluted, the DEIPA derivitised, extracted into solvent and extracts analysed by gas chromatography-flame ionisation detection. Concentrations of DEIPA averaged 107-112% of target concentrations.

Duration of treatment / exposure:

4 weeks

Frequency of treatment:

Daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0 (control), 30, 100, 1000 mg/kg bw/day
Basis:
other: Nominal concentration

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: The high dose of 1000 mg/kg bw/day represented the limit test, the remaining dose levels expected to provide dose-response data for any treatment-related effects observed in the high dose groups and to determine a no-observed-effect level (NOEL).
- Rationale for animal assignment (if not random): Stratified by body weight and then randomly assigned to treatment groups by a computer programme [deviation from guideline]
- Rationale for selecting satellite groups: No data
- Post-exposure recovery period in satellite groups: Additional groups administered 0 or 1000 mg/kg bw/day were held for a two week recovery period
- Section schedule rationale (if not random): No data

Positive control:

None specified

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily
- Cage side observations included evaluation of skin, fur, mucous membranes, respiration, nervous system function, animal behaviour, moribundity, mortality and the availability of feed and water.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Pre study and weekly for 4 weeks

BODY WEIGHT: Yes
- Time schedule for examinations: Pre study and weekly thereafter

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Not applicable

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

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Not applicable

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations:Before start of study and prior to necropsy for all animals designated to 4-week toxicity study. For those satellite animals, eyes were examined after the 2-week recovery period.
- Dose groups that were examined: All

HAEMATOLOGY: Yes
- Time schedule for collection of blood: At the scheduled necropsy
- Anaesthetic used for blood collection: Yes (methoxyflurane)
- Animals fasted: Yes
- How many animals: All
- Parameters examined included prothrombin time, haematocrit, haemoglobin concentration, erythrocyte count, total leukocyte count, platelet count, differential leukocyte count and erythrocyte, leukocyte and platelet morphology.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At the scheduled necropsy
- Animals fasted: Yes
- How many animals: All
- Parameters examined included enzyme activity and concentrations of urea nitrogen, protein, globulin, cholesterol, triglycerides and electrolytes and (4 week toxicity study only) glucose, creatine and total bilirubin.

URINALYSIS: Yes
- Time schedule for collection of urine: Week prior to necropsy
- Metabolism cages used for collection of urine: No
- Animals fasted: No
- Parameters examined included specific gravity and (for 4 week toxicity study only) colour and appearance. Semiquantitative analysis of pH, bilirubin, glucose, proteins, ketones, blood and urobilinogen for the 4-week toxicity study.

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: Prior to the start of the study and during last week of treatment.
- Dose groups that were examined: All
- Battery of functions tested: sensory activity / grip strength / motor activity

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, examination of external tissues and all orifices. Cranial cavity opened for the brain, pituitary and adjacent cervical tissues to be examined. The eyes were examined in situ by application of a moistened glass slide to each cornea. The nasal cavity was flushed via the the nasopharyngeal duct and lungs distended to an approximately normal insipratory volume with neutral , phosphate buffered 10% formalin using a syringe and blunt needle. The skin was relected from the carcass, the thoracic and abdominal cavities were opened and viscera examined. The brain, liver, kidneys, heart, adrenals, testes, epididymides, thymus and spleen were trimmed and weighed immediately for the 4-week toxicity study. The liver and kidney were trimmed and weighed immediately for the satellite groups.

HISTOPATHOLOGY: Yes , all of the following tissues examined by standard histologic procedures in the high and control groups, all tissues microscopically examined in the low and mid-dose group animals. Only the stomach was evaluated for the satellite group animals.

(Adrenals, kidneys, prostate, aorta, lacrimal/harderian glands, rectum, auditory sebaceous glands, larynx, salivary glands, bone (including joint), liver, seminal vesicles, bone marrow, lungs, skeletal muscle, brain (cerebrum, brainstem, cerebellum), mammary gland, skin and subcutis, cecum, mediastinal lymph node, spinal cord (cervical, thoracic, lumbar), cervix, mediastinal tissues, spleen, coagulating glands, mesenteric lymph node, stomach, colon, mesenteric tissues, testes, duodenum, nasal tissues, thymus, epididymides, oral tissues, thyroid gland, esophagus, ovaries, tongue, eyes, oviducts, trachea, gross lesions, pancreas, urinary bladder, heart, parathyroid glands, uterus, ileum, peripheral nerve, vagina, jejunum, pituitary).

Other examinations:

Rectal temperature

Statistics:

Means and standard deviations were calculated for all continuous data.
In-life body weights evaluated using a analysis of variance (ANOVA).
Final body weight, organ weight, haematologic parameters, clinical chemistry parameters and urine specific gravity evaluated by using a two-way ANOVA. Comparisons of individual dose groups to the control group made with Dunnett's test.
Epididymides and testes weight analysed using a one-way ANOVA.
Rectal temperature and grip performance were analysed by a factorial analysis of covariance (ANCOVA).
Motor activity was analysed by a factorial repeated measures design.
All parameters were analysed for equality of variance using Bartlett's test.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not specified

Description (incidence and severity):

not applicable

Food efficiency:

not examined

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

not specified

Description (incidence and severity):

not applicable

Ophthalmological findings:

no effects observed

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

effects observed, treatment-related

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not specified

Description (incidence and severity):

none reported

Details on results:

CLINICAL SIGNS AND MORTALITY
No mortality and no treatment-related clinical observations at any dose level

BODY WEIGHT AND WEIGHT GAIN
No statistically significant differences in terminal body weights and body weight gains of any treated group compared to controls during the 4-week study period. Statistical signs of decreases in body weight seen at 1 and 2-week of recovery, period, however not considered to be of toxicological significance.

FOOD EFFICIENCY
Not examined

OPHTHALMOSCOPIC EXAMINATION
No treatment-related findings

HAEMATOLOGY
The only statistical alteration in haemotology parameters was a minimal decrease in mean haemoglobin concentration of both sexes combined in the high dose group. Statistically identified minimal decreases in the mean prothrombin time of both sexes combined , present in the low and high dose groups.

CLINICAL CHEMISTRY
Statistically-identified increase in mean urea nitrogen, aspartate aminotransferase, and (including after the 2-week recovery period) total protein, albumin, triglycerides and calcium for both sexes in the high-dose group. A statistically-identified decrease in mean cholesterol was noted for females in the high-dose group in 4-week toxicity study animals.

URINALYSIS
Statistically-significant decrease in mean urine specific gravity for both sexes combined in the mid and high dose groups. This decrease was not apparent in females following the 2-week recovery period, and it had significantly improved for males.

NEUROBEHAVIOUR
No treatment-related findings

ORGAN WEIGHTS
Statistically significant increase in mean absolute and relative kidney and liver weights of both sexes combined in the high-dose group, possibly treatment-related.

GROSS PATHOLOGY
No treatment-related gross pathologic observations

HISTOPATHOLOGY: NON-NEOPLASTIC
All males and females in the high-dose group had stomach alterations consisting of slight to moderate inflammation, hyperplasia and/or hyperkeratosis of the non-glandular mucosa at the limiting ridge. One female at this dose also had a focal erosion of the hyperplastic non-glandular mucosa. All treatment-related stomach alterations were completely resolved following the 2-week recovery period. No treatment-related findings seen in the lower mid-dose groups.

OTHER FINDINGS: RECTAL TEMPERATURE
No treatment-related findings

Effect levels

Dose descriptor:

NOAEL

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

In a GLP study, conducted according to OECD guideline 407, a NOAEL of 100 mg/kg bw/day has been determined in the rat for DEIPA, following gavage administration for 28 days.

Executive summary:

In a GLP study, conducted according to OECD guideline 407, groups of 5 female and 5 male Fischer rats were administered 0 (control), 30, 100 and 1000 mg/kg bw/day of DEIPA (in water) by oral gavage for 28 days. Recovery was assessed in a two-week recovery period following a 4-week dosing regime, in additional groups administered 0 (control) or 1000 mg/kg bw/day. Parameters evaluated included mortality, detailed clinical observations, functional tests, ophthalmologic examination, body weight, feed consumption, clinical chemistry, haematology, urinalysis, selected organ weights, gross and histopathologic examination.

There were no mortalities or treatment-related clinical observations at any dose level. The most significant effects noted were inflammation, hyperplasia and hyperkeratosis of the non-glandular mucosa of the stomach in rats receiving 1000 mg/kg bw/day. All treatment-related stomach alterations were completely resolved following the 2 -week recovery period. Both sexes administered 1000 mg/kg bw/day showed statistically significant increases in liver and kidney weights (but no associated tissue effects), a minimal decrease in haemoglobin concentration and increases in urea nitrogen, aspartate aminotransferase, total protein, albumin, triglycerides and calcium. The high dose rats had reduced urine specific gravity. This was also seen in females at 100 mg/kg bw/day, however this was not considered significant as there were no associated toxicological alterations. There was partial or complete recovery of all treatment-related effects in the high dose group following the 2-week recovery period. 

From the results of this study, an oral no-observed-adverse-effect level (NOAEL) of 100 mg/kg bw/day has been determined in the rat for DEIPA.