Carbonic acid, compound with 2-aminoethanol (1:2)

Repeated dose toxicity: oral

Administrative data

Endpoint:

repeated dose toxicity: oral, other

Remarks:

other: two-generation reproductive toxicity study

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

1994

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 416 (Two-generation reproduction toxicity study)

Deviations:

yes

Remarks:

Food consumption was not determined between days 14 and 21 after parturition

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-aminoethanol

EC Number:

205-483-3

EC Name:

2-aminoethanol

Cas Number:

141-43-5

Molecular formula:

C2H7NO

IUPAC Name:

2-aminoethanol

Details on test material:

- Name of test material (as cited in study report): Monoethanolamin-hydrochlorid (2-Aminoethanol) Test substance Nos: 1) 05/0372-2; 2) 05/03723; 3) 05/0372-4
- Analytical purity: >99 %
- Physical state: solid / white
- Date of production: ad 1) 04 Aug 2006; ad 2) 14 Aug 2006; ad 3) 15 Sep 2006
- Lot/batch No.: ad 1) JB116/2+3 (from 09 Aug – 04 Oct 2006); ad 2) JB116/4 (from 04 Oct – 29 Nov 2006); ad 3) JB116/9-17 (from 29 Nov 2006 until the scheduled termination of the in life part of the study)
- Storage condition of test material: Room temperature, under N2

Test animals

Species:

rat

Strain:

other: Crl:WI (Han)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services GmbH, Germany
- Age at study initiation: (P) 16 days
- Weight at study initiation: (P) Males: 162.1 (142.5 – 186.5) g ; Females: 126.2 (110.6 – 145.1) g;
- Fasting period before study: none
- Housing: housed individually in type DK III stainless steel wire mesh cages
- Diet: ground Kliba maintenance diet mouse/rat “GLP” meal, supplied by Provimi Kliba SA, Kaiseraugst, Switzerland ad libitum
- Water: ad libitum
- Acclimation period: 16 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 30-70
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

DIET PREPARATION
The test substance (ethanolamine hydrochloride, EAH) was weighed and thoroughly mixed with a small amount of food. Then corresponding amounts of food, depending on the dose group, were added to this premix in order to obtain the desired concentrations. Mixing was carried out for about 10 minutes in a laboratory mixer. Test diets were prepared at intervals, which guaranteed that the test substance in the diet remained stable throughout the feeding period.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The stability of EAH in the diet over 32 days at room temperature was investigated analytically before the beginning of the study. Homogeneity and concentration control analyses were carried out at the beginning and toward the end of the premating periods. At least one analysis of test substance preparations for female animals was carried out during the gestation and lactation periods.

The analyses were carried out at the Analytical Chemistry Laboratory of Experimental Toxicology and Ecology of BASF SE, Ludwigshafen, Germany.

Duration of treatment / exposure:

semichronic duration (> 75 days)

Frequency of treatment:

daily

Doses / concentrations

Remarks:

Doses / Concentrations:
100, 300 and 1000 mg/kg bw/day
Basis:
nominal in diet

No. of animals per sex per dose:

25

Control animals:

yes, plain diet

Examinations

Observations and examinations performed and frequency:

For parental animals:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily on working days and once daily on weekends

DETAILED CLINICAL OBSERVATIONS: Yes

BODY WEIGHT: Yes
- Time schedule for examinations: body weights of F0 and F1 parents were determined once weekly; during gestation and lactation F0 and F1 females were weighed on days 0, 7, 14 and 20 of gestation, and on days 1, 4, 7, 14 and 21 after birth.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Time schedule: once weekly (over a period of at least 6 days each) and weekly during gestation (days 0-7, 7-14, 14-20 post coitum; p.c.) and lactation periods (days 1-4, 4-7, 7-14 post partum; p.p.).

OTHER:
The F1 and F2 pups were sexed on the day of birth (day 0 p.p.) and weighed on days 1, 4, 7, 14, and 21 p.p. Their viability was recorded. At necropsy, all pups were examined macroscopically (including weight determinations of brain, spleen and thymus in one pup/sex/litter).

Serum concentrations of the test substance:
Blood samples were taken from all F0 and F1 parental animals of each sex and test group during week 10 of premating treatment and the plasma was analyzed for the concentration of Ethanolamine hydrochloride

Estrous cycle data were evaluated for F0 and F1 generation females over a three week period prior to mating until evidence of mating occurred. Moreover, the estrous stage of each female was determined on the day of scheduled sacrifice.

Parameters examined in [all/P/F1] male parental generations:
motility, sperm head count, morphology

Sacrifice and pathology:

For parental animals:
All F0 and F1 parental animals were sacrificed by decapitation under Isoflurane anesthesia. The exsanguinated animals were necropsied and assessed by gross pathology, special attention was given to the reproductive organs. The liver, kidneys, adrenal glands, testes, epididmides. Cauda epididymis, prostate, seminal vesicles, ovaries, uterus, spleen, brain, pituitary gland and thyroid glands (with parathyroids) were weighed and the vagina, cervix uterie, uterus, ovaries, oviducts, left testis, left epididymis, seminal vesicles, coagulation glands, prostate, pituitary gland, adrenal glands, liver, kidneys, spleen, brain, thyroids (with parathyroids)and all gross lesions were fixed in an appropriate fixative, histologically processed and examined by light microscopy. From both ovaries (”ovary 1” and “ovary 2”) of F1 female animals (control and top dose), five sections were taken from the proximal and the distal part of the ovaries, at least 100 µm apart from the inner third of the ovary. All ovarian sections were prepared and evaluated for numbers of primordial and growing follicles.
As soon as possible after termination, one portion of the liver (lobus medialis) of each 10 dams per group was sampled to be analyzed for choline concentration.

Statistics:

See below

Results and discussion

Results of examinations

Details on results:

Clinical examinations revealed no test substance-related adverse effects for F0 and F1 parental animals of low (100 mg/kg bw/dayand mid (300 mg/kg bw/daylevels. The test compound did adversely affect food consumption of the high dose F0 females (1000 mg/kg bw/day) during lactation. Also, the body weight gain and, for F0 generation, body weights of the high-dose dams were statistically significantly less compared to the control group during gestation, which was likely be secondary to an increased post-implantation loss in these
animals.

Estrous cycle data and sexual organ weights and morphology were comparable between the F0 and F1 dams of all test groups and the corresponding controls and ranged within the historical control data of the test facility.
In the top-dose F0 and F1 males the test substance administration led to a decrease of absolute and relative organ weights of cauda epididymidis and epididymides. Furthermore, prostate weight and the number of homogenization resistant caudal epididymal sperm was slightly, but significantly decreased in the F0 males. These findings were considered to be treatment-related effects, whereas histomorphological correlates were missing.

A statistically significant increase of absolute and relative kidney weights was noted in male and female F1 animals of the mid (300 mg/kg bw/day) and top-dose (1000 mg/kg bw/day) groups. Because no histomorphological correlate was detected, the treatment-related weight increase was considered to be of no toxicological concern. As compared to control animals, the kidneys of low-, mid-, and top-dose male and female animals revealed a low incidence of basophilic tubules in a slightly higher number of animals. The severity (minimal to slight) was comparable between controls and treated animals and a clear dose-response relationship was missing. Thus this finding was considered to have no toxicological relevance.

Effect levels

Dose descriptor:

NOAEL

Remarks:

parental

Effect level:

300 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: reduced food consumption and/or body weight gain, as well as organ weight changes unaccompanied by histopathological findings

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Test substance stability:

The stability of test substance in rat diet was demonstrated for a period of 32 days at room temperature in a different batch of comparable quality, which was not used for the study. The homogeneity of the mixtures was verified. The concentration control analyses of the samples taken revealed that the values were within a range of 90-110% of the nominal concentration in all analyses at all time points, with the exception of one concentration in the feed of the high-dose group (88%).

Plasma concentrations of 2 -aminoethanol were below 3 mg/kg for all control animals, <3 - 4 mg/kg for the low dose animals, 8 - 11 mg/kg for the mid dose animals and 60 – 81 mg/kg for the high dose animals.

Toxicokinetic dataof 2 -aminoethanol (calculated as 2 -aminoethanol hydrochloride)fromthis two-generation reproduction toxicity studyshow a dose dependency of the plasma levels of 2 -aminoethanol in the experimental animals and there with prove the bioavailability of 2 -aminoethanol hydrochloride in principle.

 

Tables

Mean test substance intake (mg/kg bw/d; minimum value / maximum value)

	Test group 01 (100 mg/kg bw/d)	Test group 02 (300 mg/kg bw/d)	Test group 03 (1000 mg/kg bw/d)
F0 males	94.3 (72.4 / 102.5)	283.2 (218.4 / 309.4)	943.3 (716.7 / 1032.6)
F0 females (premating)	96.7 (80.5 / 100.7)	289.6 (241.2 / 304.9)	964.4 (792.4 / 1017.8)
F0 females (F1 litter) - gestation period - lactation period*	103.5 (92.6 / 111.6) 99.2 (81.6 / 120.2)	315.2 (284.8 / 337.9) 306.7 (249.7 / 370.3)	1043.2 (989.4 / 1084.7) 866.0 (668.6 / 1053.9)

* = Days 1–14 p.p. only

Absolute organ weights (P-generation)

Compared to the controls (= 100%), the following values (in %) were significantly changed (printed in bold):

	Male animals			Female animals
Group	01 100 mg/kg bw/d	02 300 mg/kg bw/d	03 1000 mg/kg bw/d	01 100 mg/kg bw/d	02 300 mg/kg bw/d	03 1000 mg/kg bw/d
Brain	99%	100%	97%*
Cauda epididymis	99%	102%	88%**
Epididymides	100%	101%	92%**
Prostate	92%	99%	86%**
Spleen				105%*	107%	97%

 

*: p≤0.05; **: p≤0.01

 

All other mean absolute weight parameters did not show significant differences compared to the control groups.

 

The decrease of absolute weights of cauda epididymis, epididymides, and prostate in male top-dose animals (1000 mg/kg bw/d) were considered as treatment-related effects.

 

The decrease of brain weights in top-dose males (1000 mg/kg bw/d) as well as the increase of spleen weights in low-dose females (100 mg/kg bw/d) was considered as incidental and not treatment-related due to a missing dose-response relationship.

Absolute organ weights (F1 generation)

Compared to the controls (= 100%), the following values (in %)were significantly changed (printed in bold):

 

	Male animals			Female animals
Group	11 100 mg/kg bw/d	12 300 mg/kg bw/d	13 1000 mg/kg bw day	11 100 mg/kg bw/d	12 300 mg/kg bw/d	13 1000 mg/kg bw/d
Cauda epididymis	96%	99%	88%**
Epididymides	100%	101%	91%**
Kidneys	99%	106%*	111%**	103%	106%**	115%**
Spleen	99%	103%	92%*
Thyroid glands	106%	99%	109%*	110%	118%**	111%*

 

*: p≤0.05; **: p≤0.01

All other mean absolute weight parameters did not show significant differences compared to the control groups.

The decrease of absolute weights of cauda epididymis and epididymides in male top-dose animals (1000 mg/kg bw/d) were considered to be treatment-related.

 

The increase of absolute kidney weights of male and female animals in mid- (300 mg/kg bw/d) and top-dose (1000 mg/kg bw/d) groups, respectively, was statistically significant. Because no histomorphological correlate was detected, a treatment-related weight increase was less likely.

 

The decrease of spleen weights in top-dose males as well as the increase of thyroid glands in top-dose males and mid- and top-dose females, respectively, is considered incidental and not treatment-related due to a missing dose-response relationship.

Applicant's summary and conclusion

Conclusions:

As indicated in the read across justification document, if ingested, the registered substance is expected to decompose to form monoethanolamine and therefore, it is reasonable to assume that the effects reported in this study are a worst-case for the registered substance. As such, exposure of rats over 32 d in the diet to monoethanolamine established a NOAEL of 300 mg/kg bw/day based on reduced food consumption, and/or body weight gain, as well as organ weight changes unaccompanied by histological findings. This NOAEL can be directly applied to the registered substance.