Desmedipham

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1990-10-25 to 1991-03-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

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:

Desmedipham

EC Number:

237-198-5

EC Name:

Desmedipham

Cas Number:

13684-56-5

Molecular formula:

C16 H16 N2 O4

IUPAC Name:

ethyl 3´-phenylcarbamoyloxycarbanilate

Test material form:

solid: particulate/powder

Details on test material:

The test material is Desmedipham but the purity has not been specified.

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Five male and 5 female nulliparous and non-pregnant young adult rats of the Sprague-Dawley strain were used. They were 8-10 weeks old and weighed 215-273 g at dosing. The rats were housed by sex in polypropylene cages with mesh floors suspended over absorbent paper lined trays with a maximum of 5 animals per cage. The rats were fed Rat and Mouse No. 1 Diet. Food and tap water were available ad libitum throughout the study. The diet and water are analysed on a regular basis and meet the laboratory's criteria. Mean environmental maximum and minimum temperatures were 21°C and 19°C and mean relative humidity was 50%. A 12 h light/dark cycle was in operation (light hours 0700-1900 h). The rats were allowed an acclimatisation period of 7 days before test commencement.

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

A group of 5 male and 5 female rats was prepared by clipping the backs free of hair, approximately 24 hours before application of the test material. Care was taken to avoid abrading the skin. Desmedipham was administered dermally in a single application under occlusion at a dose level of 2000 mg/kg bw. The test material was applied evenly onto a gauze dressing which was applied to the shaved back of each rat. At least 10% of the body surface was in contact with the test material. The trunk of the rat was then encircled with a strip of non-irritating tape. After a contact period of 24 hours following dosing the dressing was removed and the skin wiped with a water dampened tissue to remove excess test material.

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Remarks:

Not required for this study type

Details on study design:

- Duration of observation period following administration: 14 days.
- Frequency of observations and weighing: Observed daily. Weighed 3 times: prior to dosing, 7 days after dosing and 14 days after dosing.
- Necropsy of survivors performed: yes

Statistics:

Not specified.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: no mortality observed at the limit dose of 2000 mg/kg bw

Mortality:

None

Clinical signs:

other: other:

Body weight:

other body weight observations

Gross pathology:

There were no effects of treatment

Any other information on results incl. tables

Table 1: Desmedipham: Acute Dermal Toxicity (Limit) Test in Rats, Test Results: Mortality

Animal/Sex	Mortality	Clinical signs	Necropsy findings
11 (M)	0/5	NAD	NAD
12		NAD	NAD
13		NAD	NAD
14		NAD	NAD
15		NAD	NAD
16 (F)	0/5	NAD	NAD
17		NAD	NAD
18		NAD	NAD
19		NAD	NAD
20		NAD	NAD

 

Table 2: Desmedipham: Acute Dermal Toxicity (Limit) Test in Rats, Test Results: Body weight

Animal/Sex	Body Weight (g)
	At Dosing	After 7 Days	After 14 Days	Gain (Loss)
11 (M)	266	305	328	62
12	272	304	337	65
13	264	301	329	65
14	273	305	332	59
15	272	320	351	79
Mean	269	307	335	66
± S.D.	4	7	9	8
16 (F)	215	229	229	14
17	236	252	276	40
18	253	260	290	37
19	238	260	280	42
20	224	241	249	25
Mean	233	248	265	32
± S.D.	14	13	25	12

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The acute dermal LD50 of desmedipham in the rat was found to be >2000 mg/kg bw under the conditions of this study. Desmedipham does not therefore require classification for acute dermal toxicity in any category according to the CLP criteria.

Executive summary:

The acute dermal toxicity potential of Desmedipham, was investigated in rats.  No deaths occurred and no clinical signs were noted after a 24 hour dermal administration, under occlusion, of Desmedipham at a dose level of 2000 mg/kg bw.  No abnormalities were detected at necropsy.  The acute dermal LD₅₀ of desmedipham in the rat was found to be >2000 mg/kg bw under the conditions of this study. Desmedipham does not therefore require classification for acute dermal toxicity in any category according to the CLP criteria.