5-[(2-hydroxyethyl)amino]-o-cresol

Toxicity to reproduction

Administrative data

Endpoint:

reproductive toxicity, other

Remarks:

data from the 90 days repeated dose toxicity study

Type of information:

other: data from the 90 days repeated dose toxicity study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: data from the 90 days repeated dose toxicity study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD 408

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

5-[(2-hydroxyethyl)amino]-o-cresol

EC Number:

259-583-7

EC Name:

5-[(2-hydroxyethyl)amino]-o-cresol

Cas Number:

55302-96-0

Molecular formula:

C9H13NO2

IUPAC Name:

5-[(2-hydroxyethyl)amino]-2-methylphenol

Test material form:

solid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Titre: 99.3% (by HClO4)
- Purity test date: 30 January 1992
- Lot/batch No.: OP 202
- Expiration date of the lot/batch: no data
- Description: light beige powder
- Trade name: IMEXINE OAG

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature according to the instructions given by the Sponsor.
- Purity control of the test substance was assessed before, on week 4 and after the study.
- The test substance preparations were made on a weekly basis by the the testing laboratory, according to the known stability

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 France (76410 Saint-Aubin-lès-Elbeuf, France)
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: approximately 6 weeks old
- Weight at study initiation (mean body weight): 210 g for the males and 175 g for the females
- Fasting period before study: Approximately 24 hours after treatment, overnight fasting of animals was performed for blood samples collection.
- Housing: animals were housed in suspended wire-mesh cages (43.0 x 21.5 x 18.0 cm) and each cage contained 2 rats of the same sex and group. A metallic tray was placed under each cage and contained autoclaved sawdust (Société SICSA, 94142 Alfortville, France). Bacteriological analysis and detection of possible contaminants (pesticides, heavy metals) of the sawdust are performed periodically (Laboratoire Départemental d'Analyses, 27000 Evreux, France; Laboratoire Municipal et Régional de Rouen, 76000 Rouen, France). Bottles and sawdust were changed once a week, feeders, trays, cages and racks once every 4 weeks. Cages were not randomized in the room, but placed in order vertically on the racks. Fortnightly, all the racks were moved around clockwise, rack by rack .
- Diet: ad libitum to AO4 C pelleted diet (U.A.R/, 91360 Villemoisson-sur-Orge, France) except overnight before blood samples collection and during urine collection. The batch was analysed (composition, contaminants) by the supplier.
- Water: ad libitum to bottles containing tap water filtered with a 0.22 micron (Millipore SA, 78140 Vélizy, France). Bacteriological and chemical analyses of the water and detection of possible contaminants (pesticides, heavy metals and nitrosamines) are made periodically (Laboratoire Départemental d'Analyses, 27000 Evreux, France; Laboratoire Municipal et Régional de Rouen, 76000 Rouen, France; Centre de Nutrition Humaine, 54000 Nancy, France).
- Acclimation period: 8-days

DETAILS OF FOOD AND WATER QUALITY: There were no known contaminants in the diet, water or sawdust at levels likely to have influenced the outcome of the study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 2
- Humidity (%): 50 ± 20
- Air changes (per hr): 13 cycles of filtered, non-recycled air
- Photoperiod (hrs dark / hrs light): 12 / 12

The test substance was administered by gavage using a glass syringe fitted with a metal probe .
Each animal was given the test substance once a day, at the same approximate daily Lime, 7 days a week over a period of 13 weeks.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: 0.5 % aqueous carboxymethylcellulose

Details on exposure:

The quantity of the test substance was adjusted according to the most recently recorded body weight

PREPARATION OF DOSING SOLUTIONS:
- The test substance was suspended in the vehicle and homogenized using a magnetic stirrer .
- The test substance preparations were made on a weekly basis by the testing laboratory, according to the known stability.

VEHICLE
- A constant dose volume of 5 ml/kg/day will be used

Details on analytical verification of doses or concentrations:

The test substance was administered by gavage using a glass syringe fitted with a metal probe .
Each animal was given the test substance once a day, at the same approximate daily Lime, 7 days a week over a period of 13 weeks.
The quantity of the test substance was adjusted according to the most recently recorded body weight

Duration of treatment / exposure:

90 days

Details on study schedule:

- Dose selection rationale: determined in agreement with the sponsor following the results of a previously conducted 2 week toxicity study, in which the test substance was administered at 100, 300 or 900 mg/kg/day. In this study, the 900 mg/kg/day dose level was set as the No Observable Adverse Effect Level and 1000 mg/kg/day was therefore chosen as the maximal dose that can be administered by this route .
- Rationale for animal assignment: Groups were formed in order to obtain the same approximate mean body weight and standard deviation. The stratified body weight procedure and assigment to the treatment groups were performed using a random computer selection.
- Plasma levels of the test substance: The plasma levels of the test substance will be determined during the study : 1 millilitre of blood will be taken into a tube containing lithium heparinate from the orbital sinus under light ether anaesthesia . on week 13, 2 hours alter the last administration in the first 4
animals of each sex, in each treated group . Blood will be centrifuged and plasma will be kept frozen in individual tubes at -20 °C pending possible future analysis by the testing laboratory.

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.:

220 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10 males and 10 females per dose group

Control animals:

yes

yes, concurrent vehicle

Examinations

Parental animals: Observations and examinations:

All animals were ascrified at the end of the treatment period. the following organs were weighed wet as soon as possible after dissection: adrenals, heart kidneys, liver, ovaries, spleen, testes, thymus.

Oestrous cyclicity (parental animals):

Macrscopic and microscopic examination were perfomed on ovaries, uterus horns and cervix, vagina. Photograph was taken from the uterus of animals.

Sperm parameters (parental animals):

seminal vesicle, testes and epididymides

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Clinical signs
- No cinical signs of toxicological importance were noted in the animals given 50 or 220 mg/kg/day.
- In the animals given 1000 mg/kg/day, loud breathing was noted in 5/10 males and 4/10 females, hypokinesia was noted in 2/10 females. Ptyalism was also noted in all males and females given 1000 mg/kg/day, accompanied by regurgitation in one male and one female. These findings were considered to be treatment-related .
- Findings in relation with the staining properties of the test substance were noted as follows: brown tail and/or fur in 6/10 males given 50 mg/kg/day and all males and females given 220 or 1000 mg/kg/day, yellow or orange coloured urine in all treated animals.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

- The mean body weight gain of the males and females given 50 or 220 mg/kg/day and of the males given 1000 mg/kg/day was similar to that of respective controls.
- The mean body weight gain of the females given 1000 mg/kg/day was very slightly lower than that of controls: over the 13 weeks of the treatment period, it was 145 g vs . 166 g (i.e. -13%). Although not statistically significant, this différence, which was constant from week 9 approximately, was considered to be treatment-related .

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

The mean food consumption of the treated animals of both sexes was similar to that of respective controls.

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

- Chronic tubulo-interstitial nephropathy was noted in one female given 1000 mg/kg/day. This finding can occur spontaneously in untreated rats of this strain and age, consequently the reported weak incidence was not considered treatment-related .
- The other microscopic findings encountered were those which are commonly recorded in the rat of this strain and age. Moreover, their incidence, severity and morphological characteristics were comparatively similar in both control and treated animals and consequently were not considered to be of toxicological importance .

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

not examined

Effect levels (P0)

Key result

Dose descriptor:

NOAEL

Effect level:

ca. 220 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

clinical signs

clinical biochemistry

Target system / organ toxicity (P0)

Key result

Critical effects observed:

no

Results: F1 generation

Effect levels (F1)

Key result

Dose descriptor:

other: not examined in this study

Basis for effect level:

other:

Remarks on result:

not measured/tested

Target system / organ toxicity (F1)

Key result

Critical effects observed:

not specified

Overall reproductive toxicity

Key result

Reproductive effects observed:

no

Lowest effective dose / conc.:

1 000 mg/kg bw/day (nominal)

Treatment related:

yes

Dose response relationship:

no

Applicant's summary and conclusion

Conclusions:

No reproductive study was available, but in the 90 days repeated dose toxicity sudy on rats, where the reproducive organs for males and females are macroscopically and microscopically examined, no effects were reported.

Executive summary:

This GLP-compliant study was performed to assess the potential toxicity of 2-Methyl-5-hydroxyethylaminophenol when administered daily to Sprague-Dawley rats for 13-weeks, according to OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents) (dated 12th May 1981).

No mortalities occurred during the study.

The reproductive organs were observed for males and females and no effects were reported.

Under the experimental conditions of this study, the No Observable Adverse Effect Level (NOAEL) was defined as 220 mg/kg/day.