reaction mass of neodymium carbonate and praseodymium carbonate

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Study period:

16-JUL-2007 to 31-OCT-2008

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was performed according to OECD guideline 422 and in compliance with GLP. However, as the data are used in a read-across approach, the maximal reliability score was decreased from 1 to 2, according to Practical Guide n°6.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Dicerium tricarbonate

EC Number:

208-655-6

EC Name:

Dicerium tricarbonate

Cas Number:

537-01-9

IUPAC Name:

dicerium tricarbonate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: Approximately 10 weeks old at the beginning of the treatment period
- Weight at study initiation: At the beginning of the treatment period, the animals had a mean body weight of 419 g (range: 392 g to 442 g) for the males and 263 g (range: 239 g to 283 g) for the females
- Fasting period before study: No
- Housing: The males were individually housed, except during pairing, in wire-mesh cages (43.0 x 21.5 x 18.0 cm). The females were individually housed, except during pairing, until late gestation in wire-mesh cages (43.0 x 21.5 x 18.0 cm). The females were individually housed from late gestation, and with their litter during lactation, in polycarbonate cages (43.0 x 21.5 x 20.0 cm).
- Diet: Free access to SSNIFF R/M-H pelleted maintenance diet
- Water: Free access to bottles containing tap water (filtered with a 0.22 µm filter)
- Acclimation period: The animals were acclimated to the study conditions for a period of 7 days before the beginning of the treatment period.

ENVIRONMENTAL CONDITIONS
- Temperature: 22 ± 2°C
- Humidity: 50 ± 20%
- Air changes: About 12 cycles/hour of filtered, non-recycled air
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: From 14-AUG-2007 to 10-OCT-2007

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: 0.5% aqueous methylcellulose solution

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The test item was administered as a suspension in the vehicle. The test item was ground to fine powder using a mortar and pestle, suspended in the vehicle in order to achieve the concentrations of 30, 90 and 200 mg/mL and then homogenized using a magnetic stirrer. The test item dosage forms were prepared at a frequency based on stability data (up to 9 days) and were stored at +4°C, protected from light, prior to use.

VEHICLE
- Justification for use and choice of vehicle (if other than water): Aqueous suspension for a poorly hydrosoluble test substance, as recommended in the guideline
- Concentration in vehicle: 30, 90 and 200 mg/mL
- Amount of vehicle (if gavage): A constant volume of 5 mL/kg/day was used
- Lot/batch no. (if required): Methylcellulose batch No. 017K0052, supplied by Sigma
- Purity: No data available

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

During a pre-study period, the homogeneity, stability and concentration of two dosage forms prepared at the lowest and highest concentrations of the present study (30 and 200 mg/mL) were checked using ICP-OES (Inductively Coupled Plasma/Optical Emission Spectrometry) after validation of the analytical method. The results showed acceptable homogeneity and stability of both concentrations over 9 days at +4°C.

During the study, the concentration of the test item and homogeneity of the dosage forms was determined in samples of each control and test item dosage form prepared for use in weeks 1, 3 and 6. The results showed acceptable homogeneity and concentration of all dosage forms analyzed. Precision (RSD ≤ 10%) and accuracy (100 ± 10%) of the method were found to be satisfactory.

Details on mating procedure:

- M/F ratio per cage: One female was placed with one male
- Length of cohabitation: Each female was placed with the same male until mating occurs or 14 days had elapsed. Any pairs with no evidence of mating after 14 days were separated and the female was placed for 7 days with a different male from the same dose level group who had already mated.
- Proof of pregnancy: Confirmation of mating was made in the morning, every day up to proof of mating, by checking for the presence of a vaginal plug or of sperm in a vaginal lavage.
- Further matings after two unsuccessful attempts: No
- After successful mating each pregnant female was caged (how): Individually
- Any other deviations from standard protocol: No

Duration of treatment / exposure:

- In parent males: 15 days before mating, during the mating period (up to 3 weeks), until sacrifice (i.e. at least 4 weeks in total)
- In parent females: 15 days before mating, during the mating period (up to 3 weeks), during pregnancy, during lactation until day 5 post-partum inclusive

Frequency of treatment:

Each animal was given the appropriate dosage form once a day, at approximately the same time each day, 7 days a week.

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 150, 450, and 1000 mg/kg bw/day
Basis:
other: nominal conc. corrected from the water content

No. of animals per sex per dose:

10 males and 10 females per group

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: On the basis of a previous 14-day toxicity study in the rat in which the dose-levels of 150, 450 and 1000 mg/kg/day elicited no significant treatment-related effects.
- Rationale for animal assignment: During the pre-treatment period, the required number of animals (40 males and 40 females) was selected according to body weight and clinical condition and allocated to the groups (by sex), according to a computerized stratification procedure, so that the average body weight of each group was similar.

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: From arrival, the animals were observed once a day as part of routine examinations. From the start of treatment period, each animal was observed once a day, at approximately the same time for the recording of clinical signs.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: On all animals outside the home cage, in a standard arena, once before the beginning of the treatment period and then once a week until the end of the study.
Observations included (but were not limited to) changes in the skin, fur, eyes, mucous membranes, occurrence of secretions and excretions and autonomic activity (e.g. lachrymation, piloerection, pupil size, unusual respiratory pattern). Changes in gait, posture and response to handling as well as the presence of clonic or tonic movements, stereotypes (e.g. excessive grooming, repetitive circling) or bizarre behavior (e.g. self-mutilation, walking backwards) were also recorded.

BODY WEIGHT: Yes
- Time schedule for examinations: The body weight of each female was recorded on the first day of treatment (day 1), then once a week until mated (or until sacrifice) and on days 0, 7, 14 and 20 post-coitum and days 1 and 5 post-partum.

FOOD CONSUMPTION: Yes
The quantity of food consumed by each female was recorded once a week, over a 7 day period, from the first day of treatment through gestation (days 0-7, 7-14 and 14-20 post-coitum intervals) and lactation (days 1-5 post-partum intervals) until sacrifice. During the pairing period, food consumption was not recorded.

WATER CONSUMPTION: No

POST-MORTEM EXAMINATIONS: Yes
On day 6 post-partum, after overnight fasting, at least 14 hours, all surviving parental females were deeply anesthetized by an intraperitoneal injection of sodium pentobarbital and sacrificed by exsanguination:
- A complete macroscopic post-mortem examination was performed on all animals. This included examination of the external surfaces, all orifices, the cranial cavity, the external surfaces of the brain, the thoracic, abdominal and pelvic cavities with their associated organs and tissues and the neck with its associated organs and tissues. Special attention was paid to the reproductive organs. The numbers of corpora lutea and implantation sites were also recorded.

A microscopic examination was performed on:
- All the tissues listed in the Table 1 for the first five females of the control and high-dose groups (groups 1 and 4) sacrificed as scheduled
- All macroscopic lesions

OTHER:
MORTALITY AND MORBIDITY: Each animal was checked for mortality or signs of morbidity at least twice a day during the treatment period.

Functional Observation Battery (FOB): on the first five females, once at the end of the treatment period. This included a detailed clinical examination, measurement of reactivity to manipulation or to different stimuli and motor activity.

HEMATOLOGY: Peripheral blood
The following parameters were determined for the last five females of each group on the day of sacrifice: Erythrocytes, Hemoglobin, Mean cell volume, Packed cell volum, Mean cell hemoglobin concentration, Mean cell hemoglobin, Thrombocytes, Leucocytes, Differential white cell count with cell morphology (neutrophils, eosinophils, basophils, lymphocytes and Large Unstained Cells), Monocytes, Reticulocytes, Prothrombin time, Activated partial thromboplastin time, Fibrinogen.

BLOOD BIOCHEMISTRY:
The following parameters were determined for the last five females of each group on the day of sacrifice: Sodium, Potassium, Chloride, Calcium, Inorganic phosphorus, Glucose, Urea, Creatinine, Total bilirubin, Total proteins, Albumin, Albumin/globulin ratio, Total cholesterol, Triglycerides, Alkaline phosphatase, Aspartate aminotransferase, Alanine aminotransferase, Lactate dehydrogenase, Bile acids

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: Mating index, fertility index, gestation index, number of pups delivered

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: No
- Skeletal examinations: No
- Head examinations: No
- Other: Live birth index, viability index on day 4 post-partum, mean litter size, and pup sex ratios

Statistics:

Mean values were compared by one-way variance analysis and Dunnett test, (mean values being considered as normally distributed, variances being considered as homogeneous). Percentage values were compared by Fisher exact probability test.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
CLINICAL SIGNS AND MORTALITY: There were no treatment-related mortalities or clinical signs.

BODY WEIGHT AND FOOD CONSUMPTION: Females had lower mean body weight gains during pregnancy and lactation and lower food consumption during lactation but this may be related to the higher number of fetuses/pups in the control group. There were no effects during the pre-mating period and no effects on mean male body weight or food consumption.

REPRODUCTIVE FUNCTION: Mating performance, fertility indices, corpora lutea and implantation counts, duration of gestation, and the mean number of live pups born per litter, were similar between control females and females receiving the test material. The data are summarised in Tables 2, 3 and 4.

HAEMATOLOGY: Females treated at 1000 mg/kg bw/day had a decrease in white blood cell count (approximately 12%) when compared with control.

CLINICAL CHEMISTRY: Females treated at 1000 mg/kg bw/day had a decrease in chloride concentration and an increase in glucose, potassium, inorganic phosphorus and urea concentrations.

NEUROBEHAVIOUR: A majority of animals treated at 1000 mg/kg bw/day had an increased number of horizontal movements during the 1-hour motor activity test but there were no other effects of treatment observed during the tests performed in the functional observation battery.

HISTOPATHOLOGY: NON-NEOPLASTIC: There was microscopic treatment related in the stomach that consisted of increased incidence and/or severity of submucosal eosinophil infiltration and pyloric gland hyperplasia in rats from both sexes treated at 1000 mg/kg bw/day and 450 mg/kg bw/day. No microscopic treatment related changes were observed in the testes and ovaries.

Effect levels (maternal animals)

1

Dose descriptor:

NOAEL

Effect level:

450 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

NOEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
Mating performance, fertility indices, corpora lutea and implantation counts, duration of gestation, and the mean number of live pups born per litter, were similar between control females and females receiving the test material. The data are summarised in Tables 2, 3 and 4.

There were no effects on pup survival after birth or on pup sex. Mean pup body weight was higher at all dose-levels but the mean body weight gain was comparable to the controls. There were no relevant macroscopic findings at pup necropsy.

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Table 2: Summary of reproductive data

Dose level (mg/kg bw/d)		0	150	450	1000
Paired males + females	n	10 + 10	10 + 10	10 + 10	10 + 10
Pairs mated	n	10	10	9 (10)	10
Mating index	%	100.0	100.0	90.0 (100.0)	100.0
Mean number of days of pairing before mating	n	3.4	2.4	4.3	2.3
Pregnant female partners	n	10	8	10	10
Fertility index	%	100.0	80.0	100.0	100.0
Females with live concepti	n	10	8	10	10
Gestation index	%	100.0	100.0	100.0	100.0

( ): female with no evidence of mating

 

Table 3: Summary of delivery data

Dose level (mg/kg bw/day)	0	150	450	1000
Number of pregnant females Mean duration of gestation (days) Mean number of corpora lutea Mean number of implantations Mean pre-implantation loss (%) Mean number of pups delivered Mean post-implantation loss (%)	10 21.8 18.6 16.5 11.3 15.6 5.7	8 21.9 17.6 16.5 5.6 14.6 11.6	10 22.1 18.5 15.1 17.0 12.0 22.2	10 22.0 18.0 14.7 17.4 12.9 12.3

 

Table 4: Reproductive and litter data

Doses (mg/kg bw/day)		0	150	450	1000
Females on study	N	10	10	10	10
Females mated	N	10	10	10	10
Mating index	%	100.0	100.0	100.0	100.0
Females pregnant	N	10	8	10	10
Females fertility index	%	100.0	80.0	100.0	100.0
Females with liveborn	N	10	8	10	10
Gestation index	%	100.0	100.0	100.0	100.0
Females surviving delivery	N	10	8	10	10
Duration of gestation	Mean S.D.	21.8 days 0.4	21.9 0.4	22.1 0.6	22.0 0.0
With stillborn pups	N %	0 0.0	0 0.0	0 0.0	0 0.0
With all stillborn	N %	0 0.0	0 0.0	0 0.0	0 0.0
With entire liveborn litter dying and/or missing, cannibalized, culled
Days 0-4	N %	0 0.0	0 0.0	1 10.0	0 0.0
Days 0-5	N %	0 0.0	0 0.0	1 10.0	0 0.0
Litters with liveborn pups	N	10	8	10	10
Pups delivered (total)	N	156	117	120	129
Liveborn	Mean S.D.	15.6 2.7	14.6 2.3	12.0 5.2	12.9 4.4
Live birth index	N %	156 100.0	117 100.0	120 100.0	129 100.0
Stillborn	N %	0 0.0	0 0.0	0 0.0	0 0.0
Culled (total)	N	0	0	0	0
Cannibalized	N	2	4	2	0
Missing	N	0	0	0	0
Died	N	4	1	1	1
Liveborn, not culled prior to day 5	N	156	117	120	129
Pups dying, missing and/or cannibalized
Day 0	N %	0 0.0	0 0.0	0 0.0	0 0.0
Days 1-4	N %	6 3.8	5 4.3	3 2.5	1 0.8
Days 5-7	N %	0 0.0	0 0.0	0 0.0	0 0.0
Pups surviving 4 days	N	150	112	117	128
Viability index	%	96.2	95.7	97.5	99.2

d = ANOVA + Dunnett-test      

f = Fishers exact Test      

N = number of animals

Applicant's summary and conclusion

Conclusions:

Under the conditions of this study in Sprague-Dawley strain rats the No Observed Adverse Effect Level (NOAEL) of dicerium tricarbonate for maternal toxicity was considered to be 450 mg/kg bw/day (based on systemic effects) and the No Observed Effect Level (NOEL) for developmental effects was considered to be 1000 mg/kg bw/day.

Executive summary:

A combined repeated dose toxicity study with reproduction/developmental toxicity screening test was carried out in order to assess the test material, dicerium tricarbonate, in accordance with the standardised guideline OECD 422.

 

Three groups of 10 male and 10 female Sprague-Dawley rats were dosed once daily, by oral gavage, with the test material at dose levels of 150, 450, or 1000 mg/kg bw/day. Another group of 10 male and 10 female rats were dosed with the vehicle (0.5 % w/v methylcellulose) following the same dosing regimen as the treated animals and were used as controls.

The males were treated for 2 weeks prior to mating, then through mating, until the day prior to necropsy (ca. 4 weeks of treatment). Females were treated for 2 weeks prior to mating, then through mating, gestation and until at least Day 4 of lactation (ca. 8 weeks of treatment). 

 

The following parameters and end points were evaluated: clinical signs, bodyweights, bodyweight changes, food consumption, ophthalmology, detailed functional tests and observations, clinical pathology parameters (haematology, coagulation and clinical chemistry), gross necropsy findings, organ weights, and histopathological examinations, mating and pregnancy performance, fertility, maternal care and pup performance (litter survival and pup weights).

 

There were no adverse effects of treatment at any dose-level on mortality, clinical signs, body weight or food consumption. There were no treatment-related organ weights and macroscopic changes in female rats treated at 1000 mg/kg/day. No microscopic treatment related changes were observed in ovaries. However, females treated at 1000 mg/kg/day had lower white blood cell counts, lower chloride concentration and higher glucose, potassium, inorganic phosphorus and urea levels. Moreover, there were microscopic treatment related findings in the stomach that consisted of increased incidence and/or severity of submucosal eosinophil infiltration and pyloric gland hyperplasia in rats from both sexes treated at 1000 mg/kg/day and males at 450 mg/kg/kg. However, the microscopic findings in the stomach were likely to be related to portal-of-entry irritating effects, due to the high concentrations of the substance given as a bolus by gavage. 

 

Mating performance, fertility indices, corpora lutea and implantation counts, duration of gestation, and the mean number of live pups born per litter were similar between control and treated females. Litter survival, litter weights and mean pup weights were similar between litters derived from control and treated females.

 

In conclusion, under the conditions of this study the No Observed Adverse Effect Level (NOAEL) for maternal toxicity was considered to be 450 mg/kg bw/day (based on systemic effects) and No Observed Effect Level (NOEL) for developmental effects was considered to be 1000 mg/kg bw/day.