Phosphorus

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

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

Adequacy of study:

key study

Study period:

11 August 2011 - 08 March 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was performed according to OECD test guidelines, and in compliance with GLP, so the data is considered reliable without restriction.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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:

triiron phosphide

IUPAC Name:

triiron phosphide

Constituent 2

Reference substance name:

Triiron phosphide

EC Number:

234-682-8

EC Name:

Triiron phosphide

IUPAC Name:

234-682-8

Constituent 3

Reference substance name:

12023-53-9

Cas Number:

12023-53-9

IUPAC Name:

12023-53-9

Details on test material:

- Name of test material (as cited in study report): Fe3P, Ferrophosphorous
- Physical state: Solid (fine powder)
- Analytical purity:Phosphorous 16.0%, Carbon 0.61%, Iron as base.
- Purity test date: 24 Jan 2011
- Lot/batch No.: 1192691
- Expiration date of the lot/batch: 31 December 2011
- Storage condition of test material: Ambient temperature

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: Approximately 72 days
- Weight at study initiation: 348 - 399g (males), 230 - 287g (females)
- Housing: Polycarbonate cages with either stainless steel grid floors during mating, and solid poly carbonate floors during other phases of testing.
- Diet (e.g. ad libitum): ad libitum / free access, except overnight before routine blood sampling
- Water (e.g. ad libitum): ad libitum / free access
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 23°C
- Humidity (%): 40 to 70%
- Photoperiod (hrs dark / hrs light): 12 hours light: 12 hours dark

IN-LIFE DATES: From: 26 October 2011 (Treament commenced) To: 12 December 2011 (Last date of necropsy for main phase females)

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: 1% (w/v) aqueous methylcellulose

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

VEHICLE
- Concentration in vehicle: 10 - 100 mg/mL
- Amount of vehicle (if gavage): 10 mL/kg bw/day

Details on mating procedure:

- M/F ratio per cage: 1:1
- Length of cohabitation: Up to two weeks, or until evidence of mating was found
- Proof of pregnancy: vaginal plug or sperm in vaginal smear referred to as day 0 of gestation
- After successful mating each pregnant female was caged (how): Individually

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Formulation samples were analysed by Atomic Absorption Spectrometry, to determine Iron in the samples.

Prior to the start of treatment, the analytical method was validated with respect to specificity, limit of detection, linearity of detector response over the calibration range, precision of measurement at the lowest and highest calibration standards, and the accuracy and precision of the method, by the determination of six procedural recoveries at 1 mg/mL and 100 mg/mL. A stability tiral was also performed; formulations were found to be stable and homogenous for up to 2 hours at ambient temperature with paddle stirring, and following 15 days' refrigerated storage.

Samples from all formulations prepared in the first and last weeks of the study were analysed; the test material concentrations were found to be within acceptable limits, confirming accurate preparation.

Duration of treatment / exposure:

Main phase males and toxicity phase females were dosed for five consecutive weeks.
Main phase females were treated daily for two weeks before pairing, throughout mating, gestation and until day 6 of lactation.

Frequency of treatment:

Daily

Details on study schedule:

- Age at mating of the mated animals in the study: Approximately 12 weeks

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
100 mg/kg/day
Basis:
actual ingested

Doses / concentrations 2

Remarks:

Doses / Concentrations:
300 mg/kg/day
Basis:
actual ingested

Doses / concentrations 3

Remarks:

Doses / Concentrations:
1000 mg/kg/day
Basis:
actual ingested

No. of animals per sex per dose:

Main Phase - 10 males and 10 females per dose.
Toxicity phase - 5 females per dose

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Dose levels were decided in a 7-day preliminary study in rats, conducted at the same laboratory - refer to "7 Day rangefinding_Huntingdon Life Sciences, 2011 (FGE0026)".

Examinations

Parental animals: Observations and examinations:

Refer to Study Summary in section 7.5.1.

Oestrous cyclicity (parental animals):

For 15 days before pairing, daily vaginal smears (dry) were taken from all Main phase females, using cotton swabs moistened with saline. The smears were subsequently examined to establish the duration and regularity of the oestrous cycle. After pairing with the Main phase male, smearing was continued using pipette lavage, until evidence of mating was observed.

Sperm parameters (parental animals):

Parameters examined in male parental generations: testis weight, epididymis weight.
Seminal vesicles were subject to histopathological examination.

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: No

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
Clinical signs, litter size, Sex ratio, and bodyweight

GROSS EXAMINATION OF DEAD PUPS:
For offspring surviving to scheduled termination, a careful external examination for gross abnormalities was performed. Offspring that appeared normal externally were discarded without internal examination. Offspring which were externally abnormal were subjected to a full internal microscopic examination. Missing offspring and those grossly autolysed or cannibalised could not be examined; all other offspring which died before day 7 of age were examined as detailed. The necropsy also included an assessment for the presence of milk in the stomach, where possible.

Postmortem examinations (parental animals):

Refer to Gross Pathology and Histopathology in section 7.5.1.

Postmortem examinations (offspring):

Microscopic examination, as described in "Litter Observations", above.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

no effects observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Other effects:

not examined

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Description (incidence and severity):

Assessment of oestrous cycles during the two week pre-pairing period showed that nearly all of the main phase females had regular 4 or 4/5 day oestrous cycles and it was considered that this parameter was not affected by treatment with Fe3P.

Reproductive function: sperm measures:

no effects observed

Description (incidence and severity):

The seminiferous tubules of the testes were evaluated with respect to their stage in the spermatogenic cycle and the integrity of the various cell types present within the different stages. No cell or stage abnormalities were noted.

Reproductive performance:

no effects observed

Description (incidence and severity):

The pre-coital interval was unaffected by treatment, with animals mating at the earliest opportunity, when the female came into oestrus.
Mating performance and fertility as assessed by percentage mating, conception rate and fertility index, were unaffected by treatment.
The gestation length was within the normal range of 22 to 23 days for all animals and the gestation index was unaffected by treatment.
food

Details on results (P0)

Refer to detailed analysis of toxicological parameters in section 7.5.1.

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS)
Assessment of oestrous cycles during the two week pre-pairing period showed that nearly all of the main phase females had regular 4 or 4/5 day oestrous cycles and it was considered that this parameter was not affected by treatment with Fe3P.

REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS)
The seminiferous tubules of the testes were evaluated with respect to their stage in the spermatogenic cycle and the integrity of the various cell types present within the different stages. No cell or stage abnormalities were noted.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
The pre-coital interval was unaffected by treatment, with animals mating at the earliest opportunity, when the female came into oestrus.
Mating performance and fertility as assessed by percentage mating, conception rate and fertility index, were unaffected by treatment.
The gestation length was within the normal range of 22 to 23 days for all animals and the gestation index was unaffected by treatment.

Effect levels (P0)

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reproductive function (oestrous cycle)

reproductive function (sperm measures)

reproductive performance

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

Details on results (F1)

VIABILITY (OFFSPRING)
The mean number of implantations and the live litter size on Days 1, 4 and 7 were similar to control values and unaffected by treatment.
Offspring survival up to Day 7 of age was unaffected by parental treatment.

CLINICAL SIGNS (OFFSPRING)
Refer to table in "Any other information on results".

BODY WEIGHT (OFFSPRING)
Mean bodyweights of male and female offspring of all groups of parents treated with Fe3P were marginally lower than in Controls on Day 1 of age but differences did not attain statistical significance and there was considered to be no effect of treatment on mean bodyweight gains of the offspring between Days 1 and 4 of age. However, between Day 4 and Day 7 of age, mean bodyweight gains of male and female offspring of all groups of parents treated with Fe3P were lower than in Controls and the differences attained statistical significance in the 1000 or 300 mg/kg/day groups (77-80% of Controls) and they showed a dose response. Overall bodyweight gain, between Days 1-7, was statistically lower in all male offspring of all groups of parents treated with Fe3P.

GROSS PATHOLOGY (OFFSPRING)
Macroscopic examination of offspring dying before scheduled termination or killed at scheduled termination on Day 7 of age did not reveal any findings that were attributed to parental treatment.

OTHER FINDINGS (OFFSPRING)
Sex ratio, as expressed in terms of % males, was not affected by parental treatment.

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

1 000 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

viability

sexual maturation

clinical signs

mortality

body weight and weight gain

gross pathology

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Summary of offspring clinical observations

Observation	Group (Dose mg/kg/day)
	1 (0)	2 (100)	3 (300)	4 (1000)
	Number of offspring (litters) affected
Head: bruising and swelling	1(1)
Head: bruising		1(1)	1(1)	1(1)
Umbilical cord attached	1(1)
Missing	2(2)		1(1)	2(2)
Tail absent	1(1)
Dorsal surface: Scab and reddening		1(1)
Found dead		1(1)
Forepaw: Scab		1(1)
Colour: Pale			1(1)

Applicant's summary and conclusion

Conclusions:

The No Observed Adverse Effect Level (NOAEL) for Fe3P for reproductive and developmental effects was considered to be 1000 mg/kg/day.