Dimethyl methylphosphonate

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: scientifically acceptable study (only one dose level)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1976

Report date:

1976

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Principles of method if other than guideline:

Determination of acute toxicity (LD50) after acute dermal application of the test substance to rats

GLP compliance:

no

Remarks:

well documented study

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dimethyl methylphosphonate

EC Number:

212-052-3

EC Name:

Dimethyl methylphosphonate

Cas Number:

756-79-6

Molecular formula:

C3H9O3P

IUPAC Name:

dimethyl methylphosphonate

Details on test material:

- Name of test material (as cited in study report): 80 021/B
No additional data

Test animals

Species:

rat

Strain:

other: Tif: RAI (SPF)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: healthy random bred rats purchased from local suppliers
- Age at study initiation: no data
- Weight at study initiation: 105 to 155 grams
- Fasting period: animals were fasted overnight before treatment
- Housing: during the treatment and observation period the animals were housed in groups of 5 in Macrolon cages- (size 3)
- Diet (e.g. ad libitum): standard diet of Nafag
- Water (e.g. ad libitum): drinking water
- Acclimation period: a minimum of 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±1°C
- Humidity (%): 55±5%
- Photoperiod (hrs dark / hrs light): 14 hours light cycle day

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: about 100 cm2/kg body weight was shaved on the back of the rats by means of an electric clipper
- % coverage: not specified
- Type of wrap if used: the substance was applied by evenly dispersing it on the skin with a syringe and covered with occlusive dressing, which was held around the trunk with an adhesive elastic bandage

REMOVAL OF TEST SUBSTANCE
- Washing (if done): not specified
- Time after start of exposure: after 24 hours the dressingswere taken off carefully

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 4 ml/kg bw; 1 group of 5 male and 5 female rats received maximum volume of indiluted test substance.

Duration of exposure:

24 hours

Doses:

4 ml/kg bw, corresponding to 4640 mg/kg bw (calculated assuming a test substance density of 1.16 g/cm3)

No. of animals per sex per dose:

5

Control animals:

other: yes, concurrent treated with drinking water

Details on study design:

- Duration of observation period following administration: 8 days
- Frequency of observations and weighing: not specified
- Necropsy of survivors performed:
- Other examinations performed: during this observation period symptoms and mortality were recorded. Local effects (erythema and edema) were also scored according to the OECD scoring system

Statistics:

none reported

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 4 mL/kg bw

Remarks on result:

other: corresponding to 4640 mg/kg bw (calculated assuming a test substance density of 1.16 g/cm3); no animal died at this unique dose level

Mortality:

No mortality was observed until the end of the observation period

Clinical signs:

other: All animals showed no symptoms

Gross pathology:

no data

Other findings:

- Other observations: the test substance caused irritation to the rat skin (see Table 2 and 3), all reversible within 6 days (observation period: 7 days)

Any other information on results incl. tables

Table 1: Body weight

Dose (ml/kg) bw / mg/kg bw	Concentration (%)	Body weight (g)
		Pretest	On day 8 of test
0 / 0	0	196	171
4 / 4640	100	118	148

 

Table 2: Erythema scores assuming

Time point	Individual and mean erythema scores
	Male animals					Male animals					Mean all animals
	1^st	2^nd	3^rd	4^th	5^th	6^th	7^th	8^th	9^th	10^th
24 h	2	2	2	2	2	2	2	2	2	2	2
48 h	2	2	2	2	2	2	2	2	2	2	2
72 h	2	1	1	1	1	1	1	1	1	1	1.1
6 d	0	0	0	0	0	0	0	0	0	0	0
Mean 24-48-72 h	2.0	1.7	1.7	1.7	1.7	1.7	1.7	1.7	1.7	1.7	1.7

 

Table 3: Edema scores

Time point	Individual and mean edema scores
	Male animals					Male animals					Mean all animals
	1^st	2^nd	3^rd	4^th	5^th	6^th	7^th	8^th	9^th	10^th
24 h	2	3	3	3	3	2	2	2	2	2	2.4
48 h	2	3	2	2	2	2	2	2	2	2	2.1
72 h	2	2	2	2	2	1	1	1	1	1	1.1
5 d	0	0	0	0	0	0	0	0	0	0	0
Mean 24-48-72 h	2.0	2.7	2.3	2.3	2.3	1.7	1.7	1.7	1.7	1.7	2.0