Reaction mass of [[(2-hydroxyethyl)imino]dimethylene]bisphosphonic acid, sodium salt and 4-(Phosphonomethyl)-2-hydroxy-2-oxo-1,4,2-oxazaphosphorinane, sodium salt

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was performed between 16 May 2012 and 30 May 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: Japanese Ministry of Agriculture, Forestry and Fisheries (MAFF), Testing Guidelines for Toxicology Studies, 12 NohSan No. 8147, amended 26 June 2001

Deviations:

no

Test guideline 5

Qualifier:

according to guideline

Guideline:

other: Japanese Ministry of Health and Welfare, 1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

tetrasodium 4-(hydrogen phosphonatomethyl)-2-oxo-1,4,2λ⁵-oxazaphosphinan-2-olate hydrogen {[(hydrogen phosphonatomethyl)(2-hydroxyethyl)amino]methyl}phosphonate

EC Number:

939-513-8

Molecular formula:

C4H12NNaO7P2, C4H11NNa2O7P2 and C4H10NNa3O7P2

IUPAC Name:

tetrasodium 4-(hydrogen phosphonatomethyl)-2-oxo-1,4,2λ⁵-oxazaphosphinan-2-olate hydrogen {[(hydrogen phosphonatomethyl)(2-hydroxyethyl)amino]methyl}phosphonate

Test material form:

other: white paste

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Five male and five female Wistar (RccHan:WIST) strain rats were supplied by Harlan Laboratories UK Ltd., Oxon, UK. On receipt the animals were randomly allocated to cages. The females were nulliparous and non pregnant. After an acclimatisation period of at least five days the animals were selected at random and given a number unique within the study by indelible ink-marking on the tail and a number written on a cage card. At the start of the study the animals weighed at least 200 g, and were eight to twelve weeks of age. The weight variation did not exceed ±20% of the mean weight for each sex.

The animals were housed in suspended solid floor polypropylene cages furnished with woodflakes. The animals were housed individually during the 24 Hour exposure period and in groups of five, by sex, for the remainder of the study. Free access to mains drinking water and food (2014C Teklad Global Rodent diet) was allowed throughout the study. The diet, drinking water and bedding were routinely analysed and were considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study.

The temperature and relative humidity were set to achieve limits of 19 to 25°C and 30 to 70% respectively. Any occasional deviations from these targets were considered not to have affected the purpose or integrity of the study. The rate of air exchange was at least fifteen changes per hour and the lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve hours darkness.

The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

PREPARATION OF TEST ITEM:
The test item contains 10.95% water. For the purposes of the study the test item concentration was corrected for this. The test item was weighed out according to each animal's individual bodyweight and moistened with distilled water prior to application.
The absorption of the test item was not determined.

TEST SITE
On the day before treatment the back and flanks of each animal were clipped free of hair.

Using available information on the toxicity of the test item, a group of five male and five female rats was treated with the test item at a dose level of 2246 mg/kg (equivalent to 2000 mg active ingredient/kg bodyweight).

The appropriate amount of test item, moistened with distilled water, was applied as evenly as possible to an area of shorn skin (approximately 10% of the total body surface area). A piece of surgical gauze was placed over the treatment area and semi-occluded with a piece of self-adhesive bandage. The animals were caged individually for the 24-Hour exposure period. Shortly after dosing the dressings were examined to ensure that they were
securely in place.

REMOVAL OF TEST SUBSTANCE:
After the 24-Hour contact period the bandage was carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with distilled water to remove any residual test item. The animals were returned to group housing for the remainder of the study period.

Duration of exposure:

24 hours

Doses:

2246 mg/kg (equivalent to 2000 mg active ingredient/kg bodyweight).

No. of animals per sex per dose:

5 male and 5 female at 2246 mg/kg (2000 mg ai/kg bodyweight).

Control animals:

not required

Details on study design:

- Duration of observation period following administration: 14 days

- Frequency of observations and weighing:
The animals were observed for deaths or overt signs of toxicity ½, 1, 2 and 4 hours after dosing and subsequently once daily for fourteen days.

After removal of the dressings and subsequently once daily for fourteen days, the test sites were examined for evidence of primary irritation and scored according to the Draize scale (see evaluation of skin reactions).

Any other skin reactions, if present were also recorded.

Individual bodyweights were recorded prior to application of the test item on Day 0 and on Days 7 and 14.

- Necropsy of survivors performed: yes
At the end of the study the animals were killed by cervical dislocation. All animals were subjected to gross necropsy. This consisted of an external examination and opening of the abdominal and thoracic cavities. The appearance of any macroscopic abnormalities was recorded. No tissues were retained.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

>= 2 000 mg/kg bw

Based on:

act. ingr.

Remarks on result:

other: Equivalent to >1580 mg/kg bw active acid

Mortality:

Individual mortality data are given in Table 1 (see attached background material).
There were no deaths.

Clinical signs:

other: Individual clinical observations are given in Table 1 (see attached background material). There were no signs of systemic toxicity.

Gross pathology:

Individual necropsy findings are given in Table 5 (see attached background material).
No abnormalities were noted at necropsy.

Other findings:

Dermal Reactions:
Individual dermal reactions are given in Table 2 and Table 3 (see attached background material).
There were no signs of dermal irritation.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The acute dermal median lethal dose (LD50) of the test item in the Wistar strain rat was found to be greater than 2246 mg/kg bodyweight (equivalent to 2000 mg active ingredient/kg bodyweight, equivalent to to 1580 mg/kg bw active acid).