Pentacalcium hydroxide tris(orthophosphate)

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

No data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Study performed 1974 before guidelines were available but meets generally accepted scientific standards with acceptable restrictions. Deficinencies are: food consumption not reported; uterine weights and corpora lutea not determined; one third used for visceral examination, should be 50%; test substance identification (batch etc) missing; no details on housing conditions/source of animals; administration only during periods of organogenesis; no explanation for dose choice, no statistics, no historical data

Justification for type of information:

refer to analogue justification provided in IUCLID section 13

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1974

Report date:

1973

Materials and methods

Test guideline

Test guideline 1

Qualifier:

no guideline followed

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Version / remarks:

2001

Deviations:

yes

Remarks:

food consumption not reported; uterine weights and corpora lutea not determined; one third used for visceral examination; test substance identification missing; administration only during periods of organogenesis, no statistics, no historical data

Principles of method if other than guideline:

Adult female albino CD-1 mice were mated with young adult males. Observation of a vaginal sperm plug was considered as Day 0 of gestation. Dosing by oral intubation with a control (vehicle at level equivalent to group receiving the highest dose or aspirin at 150 mg/kg) or test article in a water suspension (10 mL/kg bw) at 4.65, 21.6, 100.0 and 465.0 mg/kg bw was carried out daily on Days 6 to 15 of gestation. Observations of body weight, appearance, behaviour, and food consumption were performed. On Day 17 of gestation all dams underwent Caesarean section. Implantation sites, resorption sites and live/dead foetuses recorded. Body weights of live pups recorded. Urogenital tract of each dam examined for anatomical normality. All foetuses examined grossly for presence of external congenital abnormalities. One third foetuses of each litter underwent detailed visceral examination and the remaining two thirds were cleared in potassium hydroxide, stained with alizarin red S dye and examined for skeletal defects.

GLP compliance:

no

Remarks:

Study predates GLP

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

calcium dihydrogenorthophosphate monohydrate

IUPAC Name:

calcium dihydrogenorthophosphate monohydrate

Constituent 2

Reference substance name:

10031-30-8

EC Number:

600-059-8

Cas Number:

10031-30-8

IUPAC Name:

10031-30-8

Details on test material:

- Name of test material (as cited in study report): FDA 71-81 (Monocalcium phosphate; monohydrate)
- Physical state: Fine white crystalline material

Test animals

Species:

mouse

Strain:

other: albino CD-1

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Outbred
- Age at study initiation: No data
- Weight at study initiation: 29.2 - 30.6 g
- Housing: Gang housing in disposable plastic cages
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: No data


ENVIRONMENTAL CONDITIONS
- Temperature (°C): No data, temperature controlled rooms
- Humidity (%): No data, humidity controlled rooms

IN-LIFE DATES: No data

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
VEHICLE: Water
- Amount of vehicle (if gavage): 10 mL/kg bodyweight

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

- Impregnation procedure: cohoused
- Proof of pregnancy: vaginal plug referred to as day 0 of pregnancy

Duration of treatment / exposure:

10 days (Day 6 to Day 15 of gestation)

Frequency of treatment:

Daily

Duration of test:

17 days

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

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

Remarks:

test substance

Doses / concentrations 2

Dose / conc.:

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

Remarks:

test substance

Doses / concentrations 3

Dose / conc.:

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

Remarks:

test substance

Doses / concentrations 4

Dose / conc.:

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

Remarks:

test substance

Doses / concentrations 5

Dose / conc.:

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

Remarks:

Aspirin

No. of animals per sex per dose:

Table 1 Number of animals dosed
Material Dose (mg/kg) Total
Mated Pregnant
Sham 0.0 25 22
Aspirin 150.0 25 20
FDA 71-81 4.65 25 24
21.6 26 19
100.0 23 22
465.0 25 23

Control animals:

yes, sham-exposed

other: positive control: 150 mg/kg bw aspirin

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Appearence, behaviour, food consumption and weight observed daily.
DETAILED CLINICAL OBSERVATIONS: No
BODY WEIGHT: Yes
- Time schedule for examinations: Body weights recorded on days 0, 6, 11, 15 and 17.
POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 17
- Organs examined: uterus and urogenital tract

Ovaries and uterine content:

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

Fetal examinations:

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

Statistics:

No data

Indices:

No data

Historical control data:

No

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

not specified

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

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 examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not specified

Description (incidence and severity):

Urogenital tract was observed but no data regarding this point were described in the report.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

not examined

Maternal developmental toxicity

Number of abortions:

no effects observed

Description (incidence and severity):

For sham- and test substance treated animals no abortions were observed. In the control group with Aspirin 1 animal died or aborted.

Pre- and post-implantation loss:

no effects observed

Description (incidence and severity):

Implant sites (total number/average per dam):
0 mg/kg bw: 261 / 11.9
4.65 mg/kg bw: 283 / 11.8
21.6 mg/kg bw: 225 / 11.8
100 mg/kg bw: 244 / 11.1
465 mg/kg bw: 265 / 11.5
Aspirin: 224 / 11.8

Total litter losses by resorption:

no effects observed

Description (incidence and severity):

Resorptions:
Group (mg(kg bw): 0 4.65 21.6 100 465 Aspirin
Total number: 8 19 4 12 28 20
Dams with >=1 site resorbed: 7 13 3 10 12 9
Dams with all sites resobred: - - - - 1 -
% partial resorption: 31.8 54.2 15.8 45.5 52.2 47.4
% complete resorption: - - - - 4.35 -

Early or late resorptions:

not examined

Dead fetuses:

no effects observed

Description (incidence and severity):

Dead fetuses:
Group (mg/kg bw): 0 4.65 21.6 100 465 Aspirin
Total: 1 - - 2 4 3
Dams with 1 or more dead: 1 - - 2 3 3
Dams with all dead: - - - - - -
% partial dead: 4.55 - - 9.09 13.0 15.8
% all dead: - - - - - -

Changes in pregnancy duration:

not examined

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): not examined

Changes in number of pregnant:

not examined

Effect levels (maternal animals)

1

Key result

Dose descriptor:

NOAEL

Remarks:

maternal toxicity

Effect level:

> 465 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

body weight and weight gain

clinical signs

mortality

2

Key result

Dose descriptor:

NOAEL

Remarks:

developmental toxicity

Effect level:

> 465 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

dead fetuses

necropsy findings

number of abortions

pre and post implantation loss

Maternal abnormalities

Key result

Abnormalities:

no effects observed

Results (fetuses)

Fetal body weight changes:

not examined

Description (incidence and severity):

Fetal body weights after Caesarean section were determined. The average body weights of fetuses were similar in all groups (see table 2 below).
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): not examined

Reduction in number of live offspring:

no effects observed

Description (incidence and severity):

see table 2 for details

Changes in sex ratio:

no effects observed

Description (incidence and severity):

see tabel 2 for details

Changes in litter size and weights:

not examined

Changes in postnatal survival:

not examined

External malformations:

not examined

Skeletal malformations:

effects observed, non-treatment-related

Description (incidence and severity):

increase of incomplete ossification of sternebrae and extremities was observed in the highest dose group (see table 3 below for details)

Visceral malformations:

no effects observed

Description (incidence and severity):

see details in table 4 below

Effect levels (fetuses)

1

Key result

Dose descriptor:

NOAEL

Remarks:

fetal toxicity

Effect level:

>= 465 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reduction in number of live offspring

2

Key result

Dose descriptor:

NOAEL

Remarks:

developmental toxicity

Effect level:

>= 465 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

skeletal malformations

visceral malformations

Fetal abnormalities

Key result

Abnormalities:

no effects observed

Overall developmental toxicity

Key result

Developmental effects observed:

no

Any other information on results incl. tables

Table 2 Reproduction data

Dose (mg/kg)	Sham	Aspirin	4.65	21.6	100.0	465.0
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 foetuses
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 Foetuses
Total No.*	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 foetus 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

Findings	Dose (mg/kg)
	Sham	Aspirin	4.65	21.6	100.0	465.0
Live foetuses 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
More 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	31/15	22/12	52/15	33/13
Hyoid; reduced	17/11	25/12	17/11	21/14	15/11	27/14

* Numerator = Number of foetuses affected; Denominator = Number of litters affected

** Positive control: 150 mg/kg

 

Table 4 Summary of soft tissue abnormalities

Material	Dose level (mg/kg)	Dam	Number of pups	Description
Aspirin	150.0	A 6068	1	Cleft palate; gastroschisis

Applicant's summary and conclusion

Conclusions:

Under the conditions of the study, the test material administered to pregnant mice for 10 days up to a dose level of 465 mg/kg bw showed no maternal or developmental toxicity. The NOAEL for both maternal and developmental toxicity is > 465 mg/kg bw.