Trimethyl[2-(phosphonooxy)ethyl]ammonium chloride, calcium salt (1:1)

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

The available data refer to the degradation product of calcium phosphorylcholine chloride:

- Key study. The LOAEL of 12 days of treatment and 24 days of treatment with choline chloride was 83 mg/kg bw/day, based on spermatogenesis. Based on these data, the test item does not need to be considered toxic to reproduction.

Link to relevant study records

Reference

Endpoint:

fertility, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other:

Remarks:

The endpoint addressed in this study, i.e. spermatogenesis in the male rat, does not cover completely all possible reasons for toxicity to reproduction. However, the given data indicate that the study was well-performed and meets scientific principles.

Qualifier:

no guideline available

Principles of method if other than guideline:

Male rats were injected intraperitoneally daily over 12 or 24 days with the test item. After sacrifice, testis were weighed, fixed and examined histopathologically for the stages of spermatogenesis.

GLP compliance:

not specified

Limit test:

yes

Species:

rat

Strain:

not specified

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: animal house of the Industrial Toxicology research Centre
- Age at study initiation: adult
- Weight at study initiation: 300 g
- Fasting period before study: no data
- Housing: in plastic cages in standard conditions of husbandry
- Use of restrainers for preventing ingestion (if dermal): not applicable
- Diet (e.g. ad libitum): standard animal feed (Lipton India) ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 1 week

Route of administration:

intraperitoneal

Vehicle:

water

Details on exposure:

Intraperitoneal injection

Details on mating procedure:

Not applicable

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

12 and 24 days

Frequency of treatment:

Daily

Details on study schedule:

Animals were divided into three groups: Groups I and II rats (n=25 each) were administered queous solution of choline chloride, 25 mg/rat intraperitoneally daily for 12 and 24 days. Group III (n=10) were administered distilled water only to serve as the control.
Animals of Group I were given ether anaesthesia and sacrificed on days 2,5,8,10 and 12 after 12 days of exposure. Group II animals were similarly sacrificed on days 2,5,8,10 and 12 after 24 days of exposure. Control rats were sacrified only on day 12 after both 12- and 24-day exposure schedules.

Dose / conc.:

0 mg/kg bw/day (nominal)

Dose / conc.:

25 other: mg/rat/day

Remarks:

83 mg/kg bw/day (calculated assuming 0.3 g/rat)

No. of animals per sex per dose:

Treatment groups: 25 animals
Control group: 10 animals

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: 25 mg/rat intraperitoneally daily for 12 and 24 days. This dose was approx. 18% of the LD50 value of choline chloride in adult rats (450 mg/kg i.p).
In earlier studies three doses of choline chloride, i.e. 8, 25, and 40 mg/rat, were used. Because the 25 mg/rat produced moderate effects, it was selected for the present studies. further, based on the composition of the diet and average diet consumption per day/rat, 3 to 4 mg choline is ingested by a rat per day. Thus, the present dose gave a 6 to 8-fold excess availability of choline.
- Rationale for animal assignment (if not random): random

Positive control:

no data

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: No data

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes
- Time schedule for examinations: no data

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

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

Oestrous cyclicity (parental animals):

not applicable

Sperm parameters (parental animals):

Parameters examined in males: testis weight, epididymis weight, other: Histopathological analysis

Litter observations:

not applicable

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals after day 2,5,8,10,12 after exposure.

HISTOPATHOLOGY / ORGAN WEIGHTS
For the qualitative histopathologic analysis, individual stages were identified and the tubules were divided into stage groups, viz., I-IV, V-VI, VII-VIII, IX-XII, and XIII-XIV (according to Leblond CP, Clermont Y. Definition of the stages of the cycle of the seminiferous epithelium in the rat. Ann NY Acad Sci. 1952; 55:548-73). At least 20 tubules at each stage croup (total 100 tubules) per animal were evaluated at 400 x or 1000 x magnification to analyse specific effects on testicular tissues. This included peritubular membrane status, germinal epithelial status, cytoplasmatic vacuolation, cell sloughing, epithelial disorganization, cell death and cell type loss, presence of giant cells, spermatid damage, and inhibited spermiation.
The qualitative analysis, the quantitation of spermatogonia, zygotene, and pachytenes was performed in 10 randomly selected tubules at stage XII.
Organ weights of other tissues were determined (epididymis, liver, kidney, adrenal)

Postmortem examinations (offspring):

not applicable

Statistics:

Significance for changes in data was analysed by Student t test according Snedecor GE, Cochran WH. Statistical methods. Iowa City IA: Iowas state University Press; 1967

Reproductive indices:

not applicable

Offspring viability indices:

not applicable

Clinical signs:

not specified

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

No unscheduled deaths were noted.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

The average body weight gain in control animals between days 0 and 12 following both the experimental schedules was 20.00 + 2.3 g. The weight gain in treated animals was not significantly different from control values. No data on food consumption.

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

The testis from all the animals of the control group exhibited normal histoarchitecture and active spermatogenesis.

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

effects observed, treatment-related

Description (incidence and severity):

Treatment for 24 days increased stage XII spermatogenia count by day 5 posttreatment. The effects were reversible and contents of epithelial germ cells reached almost normal levels in the course of one seminiferous epithelial cycle.

Reproductive performance:

not examined

REPRODUCTIVE FUNCTION: SPERM MEASURES / HISTOPATHOLOGY
12-Day choline chloride administration:
Animals administered Choline chloride for 12 days did not exhibit noticeable alteration in the organization of the germinal epithelium except on day 2, when epithelial vacuoles were seen at later stages. The nuclei of spermatogenic cells were pykontic at these stages but not at earlier stages. The presence of cellular debris in a few tubules suggested detachment of apical cytoplasm of Sertoli cells and sloughing of spermatogenic cells. By day 5, the testis recovered from initial injuries and the epithelium showed normal architecture through day 12. The quantitation analysis showed a partial effect on both spermatogonia and primary spermatocytes (Table 2).

24-Day choline chloride adminstration
Significant changes in testicular morphology were observed in rats exposed to Choline chloride for 24 days. Prominent features observed at day 2 included disorganization of the adluminal compartment of tubules mainly beyond stage VIII. Only a few tubules at stages I-IV were damaged. At stages V-VI epithelial vacuolation was observed. The tubules at stages IX-XIII were most damaged. Blebbing of Sertoli cell apical cytoplasm and dislodging of pachytene spermatocytes were marked at these stages. The arrangement of elongating spermatid bundles was inappropriate and part of the epithelium was devoid of elongating spermatids. In the tubules at earlier stages, at day 2, a decrease or absence of round spermatids was evidence of late pachytene degeneration earlier in time. The late pachytenes were highly eosinophilic. Sloughing of cells was found in only a few tubules in Group I as compared to those in Group II, At posttreatment day 5, spermatogonia and early primary spermatocytes in almost all the tubules were normal. Several pachytenes were necrotic and the adluminal portion of such tubules showed large gaps. At stages I-IV, the population of elongated spermatids was slightly decreased. At day 8, the tubules at stages XIII-XIV also showed gaps at the expected position of the elongating spermatids. These cells were thought to have been lost due to sloughing at earlier time intervals. By day 12, most of the tubules appeared to be regenerating and contained normal spermatogenic cells except a few necrotic pachytenes at stages XI-XII. The organization of the germinal epithelium appeared normal at earlier stages. The quantitation of spermatogenesis at stage XII showed an increase in spermatogonia at posttreatment days 5, 8, 10, and 12 (Table 2). Zygotenes were not altered in comparison to control counts. The most severe adverse effect was observed in pachytenes. Maximum depletion to 64% of control counts of these cells was noted at day 2. A marked recovery in cell counts towards normal was observed at day 12.

Key result

Dose descriptor:

LOEL

Effect level:

ca. 83 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

reproductive function (sperm measures)

Remarks on result:

other: recalculated from 25 mg/rat/day with a median body weight ranging from 300-320 g. based on mortality; body weight; organs weights; highest dose tested

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

83 mg/kg bw/day (actual dose received)

System:

male reproductive system

Organ:

germ cells

Treatment related:

not specified

Dose response relationship:

not specified

Relevant for humans:

not specified

Clinical signs:

not specified

Dermal irritation (if dermal study):

not specified

Mortality / viability:

not specified

Body weight and weight changes:

not specified

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Sexual maturation:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

not specified

Histopathological findings:

not specified

Other effects:

not specified

Behaviour (functional findings):

not specified

Developmental immunotoxicity:

not specified

Key result

Remarks on result:

not measured/tested

Key result

Reproductive effects observed:

no

Lowest effective dose / conc.:

83 mg/kg bw/day (actual dose received)

Treatment related:

no

Table 1. Testis weights of rats treated with Choline chloride

	Posttreatment day
	2	5	8	10	12	12(control)
Group I: 25 mg choline chloride/day for 12 days
Absolute weight (g)	1.18 ± 0.03	1.30 ± 0.60	1.41 ± 0.07	1.40 ± 0.16	1.48 ± 0.03	1.36 ± 0.09
Relative weight (g)	0.66 ± 0.04	0.56 ± 0.03	0.56 ± 0.03	0.51 ± 0.01	0.51 ± 0.01	0.71 ± 0.04
Group II: 25 mg choline chloride/day for 24 days
Absolute weight (g)	1.32 ± 0.13	1.51 ± 0.10	1.33 ± 0.05	1.41 ± 0.03	1.47 ± 0.07	1.55 ± 0.01
Relative weight (g)	0.53 ± 0.03	0.50 ± 0.01	0.48 ± 0.01	0.44 ± 0.01	0.51 ± 0.01	0.48 ± 0.01

The values are mean ± SE of 10 observations.

Table 2. Spermatogenic cell count at stage XII of the seminiferous epithelium following Choline chloride administration.

	Posttreatment day
	2	5	8	10	12	12(control)
Group I: 25 mg choline chloride/day for 12 days
Spermatogenia	43.23 ± 2.15	46.55 ± 3.08	50.47 ± 2.90	50.65 ± 3.50	51.12 ± 3.72	41.45 ± 2.05
Zygotenes	50.35 ± 3.68	54.02 ± 2.2	58.15 ± 2.52	62.35 ± 3.70	65.00 ± 2.55	57.35 ± 3.10
Pachytenes	65.55 ± 4.23	73.72 ± 3.50	75.50 ± 3.72	75.65 ± 3.15	71.75 ± 2.60	70.62 ± 3.00
Group II: 25 mg choline chloride/day for 24 days
Spermatogenia	50.25 ± 3.10	54.52 ± 2.68*	52.37 ± 2.60*	55.45 ± 3.35*	53.30 ± 3.57*	42.02 ± 2.28
Zygotenes	53.23 ± 3.65	53.27 ± 3.16	56.75 ± 3.88	52.40 ± 2.50	53.15 ± 3.27	56.23 ± 2.68
Pachytenes	45.25 ± 4.37*	50.25 ± 3.55*	58.60 ± 4.75	56.20 ± 3.15	62.44 ± 2.65	70.00 ± 3.20

Values are mean ± SE of 10 observations. *P<0.05.

Conclusions:

The LOEL of 24 days of treatment with choline chloride was 83 mg/kg bw/day, based on spermatogenesis. Based on these data, the test item does not need to be considered toxic to reproduction.

Executive summary:

A study which evaluates the spermatogenesis in male rats after chloine chloride administration, has been included to cover the reproductive toxicity endpoint. Choline chloride was administered intraperitoneally to 25 adult male rats at dose levels of 0 and 25 mg/rat/day (ca. 83 mg/kg bw/day) for 12 or 24 days. The administration of the test item for 12 days did not significantly alter spermatogenesis and the treatment for 24 days had only transient effects. The LOEL of 24 days of treatment with choline chloride was 83 mg/kg bw/day, based on spermatogenesis. Based on these results, the test item does not need to be classified as toxic to reproduction according to CLP Regulation (EC) no.1272/2008.

Effect on fertility: via oral route

Endpoint conclusion:

no study available

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

The available data refer to the degradation products of calcium phosphorylcholine chloride:

- Key study. A study which evaluates the spermatogenesis in male rats after choline chloride administration, has been included to cover the reproductive toxicity endpoint. Choline chloride was administered intraperitoneally to 25 adult male rats at dose levels of 0 and 25 mg/rat/day (ca. 83 mg/kg bw/day) for 12 or 24 days. The administration of the test item for 12 days did not significantly alter spermatogenesis and the treatment for 24 days had only transient effects. The LOAEL of 24 days of treatment with choline chloride was 83 mg/kg bw/day, based on spermatogenesis. Based on these results, the test item does not need to be classified as toxic to reproduction according to CLP Regulation (EC) no.1272/2008.

Effects on developmental toxicity

Description of key information

- Key study: Similar to OECD 414. The test item up to 465 mg/kg bw/day did not exhibit any maternal toxicity, foetal survival, teratogenicity in female mice CD-1. Therefore, the NOAEL in mice was higher than 465 mg/kg bw/d.

- Key study: Similar to OECD 414. The test item up to 410 mg/kg bw/day did not exhibit any maternal toxicity, foetal survival, teratogenicity in female Wistar rats. Therefore, the NOAEL in mice was higher than 410 mg/kg bw/d.

- Key study: Similar to OECD 414. The test item up to 217 mg/kg bw/day did not exhibit any maternal toxicity, foetal survival, teratogenicity in Dutch-belted rabbits. Therefore, the NOAEL in rabbit was higher than 217 mg/kg bw/d.

Link to relevant study records

Reference

Reference 1

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1973-1974

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

only one-third of each litter were examined

GLP compliance:

not specified

Limit test:

no

Specific details on test material used for the study:

Fine white crystalline material.

Species:

mouse

Strain:

CD-1

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: adult
- Weight at study initiation: 30 ± 1 g
- Fasting period before study: no data
- Housing: in disposable plastic cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum

Route of administration:

oral: gavage

Vehicle:

water

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

Virgin adult female albino outbred mice were mated with young adult males, and observation of the vaginal sperm plug was considered Day 0 of gestation.

Duration of treatment / exposure:

10 days (from day 6 to day 15 of gestation)

Frequency of treatment:

Daily

Duration of test:

17 days

Dose / conc.:

4.65 mg/kg bw/day

Dose / conc.:

21.6 mg/kg bw/day

Dose / conc.:

100 mg/kg bw/day

Dose / conc.:

465 mg/kg bw/day

No. of animals per sex per dose:

Sham: 22 animals
Positive control: 20 animals
4.65 mg/kg: 24 animals
21.6 mg/kg: 19 animals
100 mg/kg: 22 animals
465 mg/kg: 23 animals

Control animals:

yes, concurrent vehicle

other: Aspirin 150 mg/kg (positive control)

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations: appearance and behaviour.

BODY WEIGHT: Yes
- Time schedule for examinations: days 0, 6, 11, 15, and 17 of gestation

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 17
- Organs examined: sternebrae, ribs, vertebrae, skull, extremities

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No data
- Number of corpora lutea: No data
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Number of dead fetuses: Yes

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: one-third per litter
- Skeletal examinations: Yes: two-thirds per litter

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not specified

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

not specified

Number of abortions:

no effects observed

Pre- and post-implantation loss:

no effects observed

Total litter losses by resorption:

effects observed, non-treatment-related

Early or late resorptions:

not specified

Dead fetuses:

effects observed, non-treatment-related

Changes in pregnancy duration:

not specified

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): no effects observed

Changes in number of pregnant:

not specified

Other effects:

not specified

Key result

Dose descriptor:

NOAEL

Effect level:

> 465 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

dead fetuses

early or late resorptions

number of abortions

pre and post implantation loss

total litter losses by resorption

Fetal body weight changes:

no effects observed

Reduction in number of live offspring:

effects observed, non-treatment-related

Changes in sex ratio:

not specified

Changes in litter size and weights:

not specified

Changes in postnatal survival:

not specified

External malformations:

no effects observed

Skeletal malformations:

effects observed, non-treatment-related

Visceral malformations:

effects observed, non-treatment-related

Other effects:

not specified

Key result

Dose descriptor:

NOAEL

Effect level:

> 465 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

external malformations

skeletal malformations

visceral malformations

Key result

Developmental effects observed:

no

Table 1. Fate summary

Material	Dose** mg/kg	Total		Surviving at Term
		Mated	Pregnant	Total	Pregnant^1
Sham	0	25	22	25	22
Aspirin*	150	25	20	24	19
Monocalcium phosphate	4.65	25	24	25	24
Monocalcium phosphate	21.6	26	19	26	19
Monocalcium phosphate	100	23	22	23	22
Monocalcium phosphate	465	25	23	25	23

* Positive Control: 150 mg/kg

** Administered as a water solution (10 ml per kg of body weight)

¹includes all dams examined at term

 

Table 2. Reproduction data.

 

	Sham	Aspirin**	Monocalcium phosphate 4.65 mg/kg	Monocalcium phosphate 21.6 mg/kg	Monocalcium phosphate 100 mg/kg	Monocalcium phosphate 465 mg/kg
Pregnancies
Total No.	22	20	24	19	22	23
Died or aborted (before Day 17)	0	1	0	0	0	0
To term (on Day 17)	22	19	24	19	22	23
Live Litters
Total No.*	22	19	24	19	22	22
Implant sites
Total No.	261	224	283	225	244	265
Average/dam*	11.9	11.8	11.8	11.8	11.1	11.5
Resorptions
Total No.*	8	20	19	4	12	28
Dams with 1 or more sites resorbed	7	9	13	3	10	12
Dams with all sites resorbed	--	--	--	--	--	1
Per cent partial resorptions	31.8	47.4	54.2	15.8	45.5	52.2
Per cent complete resorptions	--	--	--	--	--	4.35
Live Fetuses
Total No.	252	201	261	221	230	233
Average/dam*	11.5	10.6	10.9	11.6	10.5	10.1
Sex ratio (M/F)	1.02	0.88	0.78	0.92	1.13	0.93
Dead Fetuses
Total*	1	3	--	--	2	4
Dams with 1 or more dead	1	3	--	--	2	3
Dams with all dead	--	--	--	--	--	--
Per cent partial dead	4.55	15.8	--	--	9.09	13.0
Per cent all dead	--	--	--	--	--	--
Average Fetus Weight, g	0.84	0.81	0.88	0.87	0.82	0.85

* Includes only those dams examined at term

** Positive control: 150 mg/kg

 

Table 3. Summary of skeletal findings.

 

	Sham	Aspirin**	Monocalcium phosphate 4.65 mg/kg	Monocalcium phosphate 21.6 mg/kg	Monocalcium phosphate 100 mg/kg	Monocalcium phosphate 465 mg/kg
Live Fetuses Examined (at term)	179/22	141/19	186/24	155/19	162/22	164/22
Sternebrae
Incomplete oss.	10/8	31/10	18/9	27/15	22/10	28/15
Scrambled
Bipartite	8/7	3/3	11/8	9/7	10/8	9/6
Fused
Extra		6/3
Missing	23/10	28/11	13/9	13/6	32/14	23/7
Other
Ribs
Incomplete oss.						9/4
Fused/split		2/2
Wavy		1/1	2/2
Less than 12	1/1		1/1			1/1
Less than 13	48/18	30/12	42/18	18/11	32/15	34/17
Other
Vertebrae
Incomplete oss.	9/6	9/3	2/2	1/1	11/4	13/4
Scrambled
Fused
Extra ctrs. Oss.
Scoliosis
Tail defects
Other
Skull
Incomplete closure		2/2
Missing			1/1
Craniostosis
Other, facial bones, inc.						2/1
Extremities
Incomplete oss.	7/5	5/3	2/2		10/5	14/4
Missing
Extra
Miscellaneous
Hyoid; missing	37/16	33/11	13/15	22/12	52/15	33/13
Hyoid; reduced	17/11	25/12	17/11	21/14	15/11	27/14

* Number of fetuses affected/number of litters

** Positive control: 150 mg/kg

 

Table 3-a. Summary of soft tissue abnormalities.

 

Material	Dose level (mg/kg)	Dam	Number of pups	Description
Aspirin*	150	A 6068	1	Cleft palate; gastroschisis

*Positive control: 150 mg/kg

Table 4. Average body weights of pregnant dams.

 

Material	Dose level (mg/kg)	Day 0	Day 6	Day 11	Day 15	Day 17*
Sham	0	30.5	32.7	37.1	44.1	51.3 (22)
Aspirin**	150	30.0	32.2	33.7	40.6	47.0 (19)
Monocalcium phosphate	4.65	29.3	32.3	36.5	43.7	50.2 (24)
Monocalcium phosphate	21.6	29.8	32.2	36.4	44.3	50.8 (19)
Monocalcium phosphate	100	30.6	33.5	36.7	44.0	48.1 (22)
Monocalcium phosphate	465	29.2	32.3	35.1	42.8	47.8 (23)

* Number of surviving dams in parenthesis (c.f. Table 1)

** Positive control: 150 mg/kg

Conclusions:

The test item up to 465 mg/kg bw/day did not exhibit any maternal toxicity, fetal survival, teratogenicity in female mice CD-1. Therefore, the NOAEL in mice was higher than 465 mg/kg bw/d.

Executive summary:

A study was conducted to assess the teratogenic potential of the oral administration of monocalcium phosphate in mice by a method similar to OECD 414. Starting from day 0 of gestation, female mated CD-1 mice were orally administered 0 (sham), 4.65, 21.6, 100 or 465 mg/kg bw for 10 consecutive days. A positive control group was administered in parallel with 150 mg/kg of aspirin. Maternal examinations had no clearly discernible effect on nidation or on maternal or fetal survival. Resorptions and dead fetuses were counted. One-third of the fetuses from each litter underwent detailed visceral examinations. The remaining two-thirds were examined for skeletal defects. Based on the test results, the test item up to 465 mg/kg bw/day did not exhibit any maternal toxicity, fetal survival, teratogenicity in female mice CD-1. Therefore, the NOAEL for both maternal and developmental toxicity in mice was higher than 465 mg/kg bw/d.

Reference 2

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1973-1974

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

body weight schedule

GLP compliance:

not specified

Limit test:

no

Specific details on test material used for the study:

Fine white crystalline material.

Species:

rabbit

Strain:

Dutch

Remarks:

Dutch-belted

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: adult
- Weight at study initiation: 1.84 - 2.35 Kg
- Fasting period before study: no data
- Housing: in mesh bottom cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): tap water ad libitum

Route of administration:

oral: gavage

Vehicle:

water

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

Virgin adult female rabbits, on Day 0, each doe was given an injection of 0.4 ml of human chorionic gonadotropin (400 IU) via the marginal vein. Three hours later, each doe was inseminated artificially with 0.3 ml of diluted semen from a proven donor buck using approximately 20 x 10E06 motile sperm according to the procedure described by Vogin et al (Pharmacologist 11, 282 (1969)).

Duration of treatment / exposure:

13 days (from day 6 to day 18 of gestation)

Frequency of treatment:

Daily

Duration of test:

29 days

Dose / conc.:

0 mg/kg bw/day (actual dose received)

Dose / conc.:

2.17 mg/kg bw/day (actual dose received)

Dose / conc.:

10.1 mg/kg bw/day (actual dose received)

Dose / conc.:

46.7 mg/kg bw/day (actual dose received)

Dose / conc.:

217 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

Sham: 10 animals
Positive control: 9 animals
2.17 mg/kg: 11 animals
10.10 mg/kg: 13 animals
46.7 mg/kg: 10 animals
217 mg/kg: 10 animals

Control animals:

yes, concurrent vehicle

other: 6-aminonicotinamide 2.5 mg/kg (positive control)

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations: appearance and behaviour.

BODY WEIGHT: Yes
- Time schedule for examinations: days 0, 6, 12, 18, and 29 of gestation

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 17
- Organs examined: sternebrae, ribs, vertebrae, skull, extremities

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No data
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Number of dead fetuses: Yes

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: all per litter
- Skeletal examinations: Yes: all per litter

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not specified

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

not specified

Number of abortions:

no effects observed

Pre- and post-implantation loss:

no effects observed

Total litter losses by resorption:

effects observed, non-treatment-related

Early or late resorptions:

not specified

Dead fetuses:

effects observed, non-treatment-related

Changes in pregnancy duration:

not specified

Changes in number of pregnant:

not specified

Other effects:

not specified

Key result

Dose descriptor:

NOAEL

Effect level:

> 217 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

dead fetuses

early or late resorptions

number of abortions

pre and post implantation loss

total litter losses by resorption

Fetal body weight changes:

no effects observed

Reduction in number of live offspring:

effects observed, non-treatment-related

Changes in sex ratio:

not specified

Changes in litter size and weights:

not specified

Changes in postnatal survival:

not specified

External malformations:

no effects observed

Skeletal malformations:

effects observed, non-treatment-related

Visceral malformations:

effects observed, non-treatment-related

Other effects:

not specified

Key result

Dose descriptor:

NOAEL

Effect level:

> 217 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

external malformations

skeletal malformations

visceral malformations

Key result

Developmental effects observed:

no

Table 1. Fate summary

Material	Dose** mg/kg	Total		Surviving at Term
		Mated	Pregnant	Total	Pregnant^1
Sham	0	21	12	19	10
6-AN*	2.5	18	9	16	9
Monocalcium phosphate	2.17	21	12	19	11
Monocalcium phosphate	10.10	27	17	22	13
Monocalcium phosphate	46.7	15	10	14	10
Monocalcium phosphate	217	27	10	27	10

* Positive Control: 2.5 mg/kg of 6-aminonicotinamide dosed on Day 9

** Administered as a water solution

¹includes all dams examined at term

 

Table 2. Reproduction data.

 

	Sham	6-AN**	Monocalcium phosphate 2.17 mg/kg	Monocalcium phosphate 10.10 mg/kg	Monocalcium phosphate 46.7 mg/kg	Monocalcium phosphate 217 mg/kg
Pregnancies
Total No.	12	9	12	17	10	10
Died or aborted (before Day 29)	2	0	1	4	0	0
To term (on Day 29)	10	9	11	13	10	10
Corpora Lutea
Total No.	160	117	132	191	110	121
Average/dam mated	11.4	9.75	9.43	9.55	8.46	6.37
Live Litters
Total No.*	10	8	10	13	9	8
Implant sites
Total No.	58	57	62	79	50	49
Average/dam*	5.8	6.33	5.64	6.08	5.00	4.90
Resorptions
Total No.*	7	6	9	3	7	4
Dams with 1 or more sites resorbed	4	4	2	2	4	2
Dams with all sites resorbed	--	1	1	--	1	2
Per cent partial resorptions	40.0	44.4	18.2	15.4	40.0	20.0
Per cent complete resorptions	--	11.1	9.09	--	10.0	20.0
Live Fetuses
Total No.	51	49	49	76	43	45
Average/dam*	5.10	5.44	4.45	5.85	4.30	4.50
Sex ratio (M/F)	0.96	1.13	1.29	1.30	0.87	1.05
Dead Fetuses
Total*	--	2	4	--	--	--
Dams with 1 or more dead	--	2	1	--	--	--
Dams with all dead	--	--	--	--	--	--
Per cent partial dead	--	22.2	9.09	--	--	--
Per cent all dead	--	--	--	--	--	--
Average Fetus Weight, g	39.6	37.0	39.3	39.7	36.0	39.7

* Includes only those dams examined at term

** Positive control: 2.5 mg/kg of 6-aminonicotinamide dosed on Day 9

 

Table 3. Summary of skeletal findings.

 

	Sham	6-AN**	Monocalcium phosphate 2.17 mg/kg	Monocalcium phosphate 10.10 mg/kg	Monocalcium phosphate 46.7 mg/kg	Monocalcium phosphate 217 mg/kg
Live Fetuses Examined (at term)	51/10	49/8	49/10	76/13	43/9	44/8^a
Sternebrae
Incomplete oss.	1/1			1/1	1/1
Scrambled
Bipartite
Fused					3/1	1/1
Extra						1/1
Missing
Other
Ribs
Incomplete oss.
Fused/split
Wavy
Less than 12
Less than 13
Other
Vertebrae
Incomplete oss.
Scrambled
Fused
Extra ctrs. Oss.
Scoliosis
Tail defects		1/1		1/1	1/1
Other
Skull
Incomplete closure				3/1
Missing
Craniostosis
Other, facial bones, inc.
Extremities
Incomplete oss.
Missing
Extra
Miscellaneous

* Number of fetuses affected/number of litters

Table 4. Average body weights of pregnant dams.

 

Material	Dose level (mg/kg)	Day 0	Day 6	Day 12	Day 18	Day 29*
Sham	0	2.21	2.45	2.50	2.55	2.64 (10)
6-AN**	2.5	2.20	2.29	2.50	2.50	2.59 (9)
Monocalcium phosphate	2.17	2.20	2.28	2.34	2.51	2.51 (11)
Monocalcium phosphate	10.10	2.35	2.38	2.66	2.59	2.68 (13)
Monocalcium phosphate	46.7	1.84	1.96	2.04	2.06	2.15 (10)
Monocalcium phosphate	217	2.12	2.21	2.32	2.39	2.45 (10)

* Number of surviving dams in parenthesis (c.f. Table 1)

** Positive control: 2.5 mg/kg of 6-aminonicotinamide dosed on Day 9

** Positive control: 2.5 mg/kg of 6-aminonicotinamide dosed on Day 9

Conclusions:

The test item up to 217 mg/kg bw/day did not exhibit any maternal toxicity, fetal survival, teratogenicity in Dutch-belted rabbits. Therefore, the NOAEL in rabbit was higher than 217 mg/kg bw/d.

Executive summary:

A study was conducted to assess the teratogenic potential of the oral administration of monocalcium phosphate in rabbits by a method similar to OECD 414. On day 0 of gestation, female Dutch-belted rabbits were inseminated artificially with 0.3 ml of diluted semen from a proven donor. From day 6 to day 18 the animals were orally administered 0 (sham), 2.17, 10.10, 46.7 or 217 mg/kg bw for 13 consecutive days. A positive control group was administered in parallel with 2.5 mg/kg of 6 -aminonicotinamide. Maternal examinations had no clearly discernible effect on nidation or on maternal or fetal survival. Resorptions and dead fetuses were counted. One-third of the fetuses from each litter underwent detailed visceral examinations. The remaining two-thirds were examined for skeletal defects. Based on the test results, the test item up to 465 mg/kg bw/day did not exhibit any maternal toxicity, fetal survival, teratogenicity in female mice CD-1. Therefore, the NOAEL for both maternal and developmental toxicity in mice was higher than 465 mg/kg bw/d.

Reference 3

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1973-1974

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

only one-third of each litter were examined

GLP compliance:

not specified

Limit test:

no

Specific details on test material used for the study:

Fine white crystalline material.

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: adult
- Weight at study initiation: 216-224 g
- Fasting period before study: no data
- Housing: in mesh bottom cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): tap water ad libitum

Route of administration:

oral: gavage

Vehicle:

water

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

Virgin adult female albino rats were mated with young adult males, and observation of the vaginal sperm plug was considered Day 0 of gestation.

Duration of treatment / exposure:

10 days (from day 6 to day 15 of gestation)

Frequency of treatment:

Daily

Duration of test:

20 days

Dose / conc.:

0 mg/kg bw/day (actual dose received)

Dose / conc.:

4.1 mg/kg bw/day (actual dose received)

Dose / conc.:

19.1 mg/kg bw/day (actual dose received)

Dose / conc.:

88.5 mg/kg bw/day (actual dose received)

Dose / conc.:

410 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

Sham: 21 animals
Positive control: 21 animals
4.1 mg/kg: 22 animals
19.1 mg/kg: 21 animals
88.5 mg/kg: 19 animals
410 mg/kg: 22 animals

Control animals:

yes, concurrent vehicle

other: Aspirin 250 mg/kg (positive control)

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations: appearance and behaviour.

BODY WEIGHT: Yes
- Time schedule for examinations: days 0, 6, 11, 15, and 20 of gestation

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 17
- Organs examined: sternebrae, ribs, vertebrae, skull, extremities

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No data
- Number of corpora lutea: No data
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Number of dead fetuses: Yes

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: one-third per litter
- Skeletal examinations: Yes: two-thirds per litter

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not specified

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

One rat at the dose level of 4.1 mg/kg presented hydrocephalus.

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

not specified

Number of abortions:

no effects observed

Pre- and post-implantation loss:

no effects observed

Total litter losses by resorption:

effects observed, non-treatment-related

Early or late resorptions:

not specified

Dead fetuses:

effects observed, non-treatment-related

Changes in pregnancy duration:

not specified

Changes in number of pregnant:

not specified

Other effects:

not specified

Key result

Dose descriptor:

NOAEL

Effect level:

> 410 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

dead fetuses

early or late resorptions

number of abortions

pre and post implantation loss

total litter losses by resorption

Fetal body weight changes:

no effects observed

Reduction in number of live offspring:

effects observed, non-treatment-related

Changes in sex ratio:

not specified

Changes in litter size and weights:

not specified

Changes in postnatal survival:

not specified

External malformations:

no effects observed

Skeletal malformations:

effects observed, non-treatment-related

Visceral malformations:

effects observed, non-treatment-related

Other effects:

not specified

Key result

Dose descriptor:

NOAEL

Effect level:

> 410 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

external malformations

skeletal malformations

visceral malformations

Key result

Developmental effects observed:

no

Table 1. Fate summary

Material	Dose** mg/kg	Total		Surviving at Term
		Mated	Pregnant	Total	Pregnant^1
Sham	0	25	21	25	21
Aspirin*	250	25	21	25	21
Monocalcium phosphate	4.1	28	22	28	22
Monocalcium phosphate	19.1	29	21	29	21
Monocalcium phosphate	88.5	25	19	25	19
Monocalcium phosphate	410	25	22	25	22

* Positive Control: 250 mg/kg

** Administered as a water solution

¹includes all dams examined at term

 

Table 2. Reproduction data.

 

	Sham	Aspirin**	Monocalcium phosphate 4.1 mg/kg	Monocalcium phosphate 19.1 mg/kg	Monocalcium phosphate 88.5 mg/kg	Monocalcium phosphate 410 mg/kg
Pregnancies
Total No.	21	21	22	21	19	22
Died or aborted (before Day 20)	0	0	0	0	0	0
To term (on Day 20)	21	21	22	21	19	22
Live Litters
Total No.*	21	19	22	21	19	22
Implant sites
Total No.	235	235	257	236	196	244
Average/dam*	11.2	11.2	11.7	11.2	10.3	11.1
Resorptions
Total No.*	2	63	3	3	3	2
Dams with 1 or more sites resorbed	2	13	3	3	2	1
Dams with all sites resorbed	--	2	--	--	--	--
Per cent partial resorptions	9.52	61.9	13.6	14.3	10.5	4.55
Per cent complete resorptions	--	9.52	--	--	--	--
Live Fetuses
Total No.	233	170	253	233	192	242
Average/dam*	11.1	8.10	11.5	11.1	10.1	11.0
Sex ratio (M/F)	1.33	1.07	0.92	1.03	0.92	0.87
Dead Fetuses
Total*	--	2	1	--	1	--
Dams with 1 or more dead	--	2	1	--	1	--
Dams with all dead	--	--	--	--	--	--
Per cent partial dead	--	9.52	4.55	--	5.26	--
Per cent all dead	--	--	--	--	--	--
Average Fetus Weight, g	3.62	2.43	3.85	3.69	3.56	3.65

* Includes only those dams examined at term

** Positive control: 250 mg/kg

 

Table 3. Summary of skeletal findings.

 

	Sham	Aspirin**	Monocalcium phosphate 4.1 mg/kg	Monocalcium phosphate 19.1 mg/kg	Monocalcium phosphate 88.5 mg/kg	Monocalcium phosphate 410 mg/kg
Live Fetuses Examined (at term)	165/21	124/19	174/22	162/21	133/19	168/22
Sternebrae
Incomplete oss.	45/18	49/16	31/12	36/16	42/15	45/15
Scrambled		1/1
Bipartite	1/1	13/7				1/1
Fused		1/1
Extra
Missing	27/12	92/18	6/4	5/4	22/10	16/7
Other		2/2
Ribs
Incomplete oss.		1/1				9/3
Fused/split		8/4
Wavy	17/10	51/14	16/9	15/7	11/8	47/12
Less than 12		1/1
Less than 13	5/5	71/17	2/2	1/1	2/2	4/3
Other
Vertebrae
Incomplete oss.	26/14	92/19	10/6	6/5	22/11	29/10
Scrambled
Fused
Extra ctrs. Oss.
Scoliosis
Tail defects
Other
Skull
Incomplete closure	29/12	38/12	25/11	12/6	14/10	28/10
Missing		1/1
Craniostosis
Other, facial bones, inc.		9/6
Extremities
Incomplete oss.		6/3
Missing
Extra
Miscellaneous
Hyoid; missing	15/8	51/16	13/7	14/9	8/6	22/12
Hyoid; reduced	22/11	11/7	24/10	12/7	9/8	30/14

* Number of fetuses affected/number of litters

** Positive control: 250 mg/kg

 

Table 3-a. Summary of soft tissue abnormalities.

 

Material	Dose level (mg/kg)	Dam	Number of pups	Description
Aspirin*	250	A 6068	1	Encephalomyelocels
		A7066	1	Gastroschisis
		A7070	1	Meningoencephalocele
		A7076	2	Meningoencephalocele
Monocalcium phosphate	4.1	H6028	1	Hydrocephalus

*Positive control: 250 mg/kg

 

Table 4. Average body weights of pregnant dams.

 

Material	Dose level (mg/kg)	Day 0	Day 6	Day 11	Day 15	Day 20*
Sham	0	224	246	256	276	338 (21)
Aspirin**	250	216	232	245	262	307 (21)
Monocalcium phosphate	4.10	219	238	257	280	350 (22)
Monocalcium phosphate	19.1	223	243	261	281	350 (21)
Monocalcium phosphate	88.5	223	240	257	277	341 (19)
Monocalcium phosphate	410	223	238	256	283	341 (22)

* Number of surviving dams in parenthesis (c.f. Table 1)

** Positive control: 250 mg/kg

 

Conclusions:

The test item up to 410 mg/kg bw/day did not exhibit any maternal toxicity, fetal survival, teratogenicity in female Wistar rats. Therefore, the NOAEL in mice was higher than 410 mg/kg bw/d.

Executive summary:

A study was conducted to assess the teratogenic potential of the oral administration of monocalcium phosphate in rats by a method similar to OECD 414. Starting from day 0 of gestation, female mated Wistar rats were orally administered 0 (sham), 4.1, 19.1, 88.5 or 410 mg/kg bw for 10 consecutive days. a positive control group was administered in parallel with 250 mg/kg of aspirin. Maternal examinations had no clearly discernible effect on nidation or on maternal or fetal survival. Resorptions and dead fetuses were counted. One-third of the fetuses from each litter underwent detailed visceral examinations. The remaining two-thirds were examined for skeletal defects. Based on the test results, the test item up to 410 mg/kg bw/day did not exhibit any maternal toxicity, fetal survival, teratogenicity in female Wistar rats. Therefore, the NOAEL for both maternal and developmental toxicity in mice was higher than 410 mg/kg bw/d.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

410 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Klimish score 2.

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

- Key study: A study was conducted to assess the teratogenic potential of the oral administration of monocalcium phosphate in mice by a method similar to OECD 414. Starting from day 0 of gestation, female mated CD-1 mice were orally administered 0 (sham), 4.65, 21.6, 100 or 465 mg/kg bw for 10 consecutive days. A positive control group was administered in parallel with 150 mg/kg of aspirin. Maternal examinations had no clearly discernible effect on nidation or on maternal or fetal survival. Resorptions and dead fetuses were counted. One-third of the fetuses from each litter underwent detailed visceral examinations. The remaining two-thirds were examined for skeletal defects. Based on the test results, the test item up to 465 mg/kg bw/day did not exhibit any maternal toxicity, foetal survival, teratogenicity in female mice CD-1. Therefore, the NOAEL for both maternal and developmental toxicity in mice was higher than 465 mg/kg bw/d.

- Key study: A study was conducted to assess the teratogenic potential of the oral administration of monocalcium phosphate in rabbits by a method similar to OECD 414. On day 0 of gestation, female Dutch-belted rabbits were inseminated artificially with 0.3 ml of diluted semen from a proven donor. From day 6 to day 18 the animals were orally administered 0 (sham), 2.17, 10.10, 46.7 or 217 mg/kg bw for 13 consecutive days. A positive control group was administered in parallel with 2.5 mg/kg of 6 -aminonicotinamide. Maternal examinations had no clearly discernible effect on nidation or on maternal or fetal survival. Resorptions and dead fetuses were counted. One-third of the fetuses from each litter underwent detailed visceral examinations. The remaining two-thirds were examined for skeletal defects. Based on the test results, the test item up to 465 mg/kg bw/day did not exhibit any maternal toxicity, foetal survival, teratogenicity in female mice CD-1. Therefore, the NOAEL for both maternal and developmental toxicity in mice was higher than 465 mg/kg bw/d.

- Key study: A study was conducted to assess the teratogenic potential of the oral administration of monocalcium phosphate in rabbits by a method similar to OECD 414. On day 0 of gestation, female Dutch-belted rabbits were inseminated artificially with 0.3 ml of diluted semen from a proven donor. From day 6 to day 18 the animals were orally administered 0 (sham), 2.17, 10.10, 46.7 or 217 mg/kg bw for 13 consecutive days. A positive control group was administered in parallel with 2.5 mg/kg of 6 -aminonicotinamide. Maternal examinations had no clearly discernible effect on nidation or on maternal or fetal survival. Resorptions and dead fetuses were counted. One-third of the fetuses from each litter underwent detailed visceral examinations. The remaining two-thirds were examined for skeletal defects. Based on the test results, the test item up to 465 mg/kg bw/day did not exhibit any maternal toxicity, foetal survival, teratogenicity in female mice CD-1. Therefore, the NOAEL for both maternal and developmental toxicity in mice was higher than 465 mg/kg bw/d.

Justification for classification or non-classification

Based on the available information, the substance is not classified for toxicity to reproduction in accordance with CLP Regulation (EC) No. 1272/2008.