Prop-2-yn-1-yl 1H-imidazole-1-carboxylate

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Report date:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity: Fixed Dose Procedure)

Version / remarks:

adopted on 09 October 2017

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

prop-2-yn-1-yl 1H-imidazole-1-carboxylate

EC Number:

695-595-2

Cas Number:

83395-38-4

Molecular formula:

C7H6N2O2

IUPAC Name:

prop-2-yn-1-yl 1H-imidazole-1-carboxylate

Test material form:

solid

Specific details on test material used for the study:

Physical appearance (with colour): White solid
Purity (as per Certificate of Analysis): 99.7789%
Lot No.: S021110385
Date of Manufacture: 2021.11.3
Date of Expiry: 2023.5.6
Storage Conditions: Cool and dry (+2 to +8ºC)

Test animals

Species:

rat

Strain:

Sprague-Dawley

Remarks:

Rattus norvegicus

Sex:

female

Details on test animals or test system and environmental conditions:

Source of Supply : In-house bred animals
Body Weight Range at Receipt: 201.41 g to 213.20 g
No. of Animals and Sex : Range finding study : 3 Females
Main study : 2 Females
Total of 5 females were received.
(Females used were nulliparous and non-pregnant)
Randomization was done during acclimatization period
Age at Treatment : 9 to 11 weeks
Animal Identification :
Acclimatization period: All the animals were identified by tail marking using a black marker pen.
Additionally, a cage card was displayed which included study no., cage no., sex, animal no (temporary), start date and end date of acclimatization period.
Treatment period: The animals were identified by writing last 4 digits of the animal number on tail using a red permanent marker pen. Additionally, a cage card was displayed which included study no., cage no., sex, animal no. (permanent), treatment date and date of necropsy.
Animal Numbers: Rh3957 to Rh3961
Husbandry
a. Environmental conditions:
Animals were housed under standard laboratory conditions, in an environmentally monitored air-conditioned room with adequate fresh air supply (12 to 15 air changes per hour), room temperature 19.5°C to 22.8°C and relative humidity 46% to 66%, with 12 hours fluorescent light and 12 hours dark cycle. The temperature and relative humidity were recorded once
daily.
b. Housing :
Maximum of three animals were housed in a standard polycarbonate cage (size: L 430 x B 280 x H 210 mm) with stainless steel mesh top grill having facilities for holding pelleted feed and drinking water in water bottle fitted with stainless steel sipper tube. For range finding study, animals were housed individually after treatment throughout the observation. For main study, during treatment, the animals were housed individually and after patch removal they were housed together. Clean sterilized corn cob was provided as bedding material. Paper shredding was provided as enrichment.
c. Feed :
Altromin maintenance diet for rats and mice (manufactured by Altromin Spezialfutter GmbH & Co. KG) was provided ad libitum to the animals throughout the experimental period.
d. Water :
Water was provided ad libitum throughout the acclimatization and experimental period. Deep bore-well water passed through Reverse osmosis unit was provided in plastic water bottles with stainless steel sipper tubes.

Acclimatization
Healthy and young adult animals were acclimatized for a period of five, eight and eleven days for range finding study 200 mg/kg, range finding study 1000 mg/kg and range finding study 2000 mg/kg body weight respectively and fourteen days for main study animals to laboratory conditions prior to dosing and were observed for clinical signs once daily. Veterinary examination of all the animals was performed on the day
of receipt.

Preparation of Animals
On the day before the application of the test item, fur on the dorso-lateral area of the trunk of the animals was removed by clipping closely with an electric hair clipper (approximately 6 cm × 10 cm). Care was taken to avoid abrading the skin.

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

water

Details on dermal exposure:

Route of Application and Justification for Selection:
The test item was applied topically (dermal exposure). The dermal route was selected as it is one of the probable route of exposure to human and indicates a concern for human health.

Method of Test Item Application:
Required quantity of the test item per animal (based on the individual animal day 1 body weight) was weighed on to the aluminium foil and moistened with 0.5 mL of distilled water to form a thin paste using glass rod. The thin paste of test item was taken on to porous gauze dressing which was applied uniformly over an area which was approximately 10% of the total body surface. The porous gauze dressing was then wrapped with non- irritating adhesive tape and finally, the application site was wrapped using crepe bandage. The contact period of test item was at least 24 hours. At the end of the contact period, the residual test item was washed with distilled water and dried with absorbent cotton.

Duration of exposure:

The contact period of test item was at least 24 hours.

Doses:

Range finding study: 200, 1000 and 2000 mg/kg body weight.
Main study: 2000 mg/kg body weight.

No. of animals per sex per dose:

Range finding study : 3 Females
Main study : 2 Females

Control animals:

not required

Details on study design:

The study was performed in two phases that is range finding study and main study.
Range finding study was performed with three animals (single animal per dose) and
main study was performed with two animals.
The animals were dosed in a stepwise procedure with one female in range finding
study. Since the LD50 information is not available, starting dose of 200 mg/kg body
weight was selected from the fixed dose levels of 50, 200, 1000 and 2000 mg/kg body
weight. No clinical signs and mortalities were observed at the dose level of
200 mg/kg body weight in range finding study. Further one animal was dosed at
1000 mg/kg body weight approximately after 71 hours. No clinical signs and
mortalities were observed at the dose level of 1000 mg/kg body weight in range
finding study. Next one animal was dosed at 2000 mg/kg body weight approximately
after 71 hours. No clinical signs and mortalities were observed at the dose level of
2000 mg/kg body weight in range finding study. Hence, during main study, two
animals were administered with the same dose level of 2000 mg/kg body weight
approximately after 72 hours. No clinical signs and mortalities were observed at the
dose level of 2000 mg/kg body weight. No mortality was observed at any of the dosed
steps. Hence, no further testing was carried out.

Results and discussion

Preliminary study:

Since the LD50 information is not available, in range finding study, a starting dose of
200 mg/kg body weight was selected from the fixed dose levels of 50, 200, 1000 and
2000 mg/kg body weight. No clinical signs and mortalities were observed at the dose
level of 200 mg/kg body weight in range finding study. Further one animal was dosed
at 1000 mg/kg body weight. No clinical signs and mortalities were observed at the
dose level of 1000 mg/kg body weight in range finding study. Next one animal was
dosed at 2000 mg/kg body weight. No clinical signs and mortalities were observed at
the dose level of 2000 mg/kg body weight in range finding study.

Effect levels

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

no indication of skin irritation up to the relevant limit dose level

Mortality:

No treatment related clinical signs of toxicity and mortality were observed in both range finding study and main study.

Body weight:

other body weight observations

Remarks:

No treatment related changes were observed in mean body weight and percent change in body weight with respect to day 1 in both range finding study and main study. All animals revealed physiologically normal increase in the body weight in both range finding study and main study.

Gross pathology:

No treatment related gross pathological changes were observed in any of the animals in both range finding study and main study.

Other findings:

Skin Reactions: No treatment related skin reactions were observed in both range finding study and
main study.

Any other information on results incl. tables

INDIVIDUAL ANIMAL SKIN REACTION SCORE RECORD

Phase of the Experiment	Dose (mg/kg body weight)	Sex	Animal No.	Skin Reaction Observations	Skin Reaction Score on Days
					3                (24 hour)	4                   (48 hour)	5              (72 hour)
Range Finding Study	200	F	Rh3957	ER	0	0	0
				ED	0	0	0
	1000	F	Rh3958	ER	0	0	0
				ED	0	0	0
	2000	F	Rh3959	ER	0	0	0
				ED	0	0	0
Main Study	2000	F	Rh3960	ER	0	0	0
				ED	0	0	0
		F	Rh3961	ER	0	0	0
				ED	0	0	0

F: Female; ER: Erythema; ED: Edema; 0: No erythema/edema  

Applicant's summary and conclusion

Interpretation of results:

Category 5 based on GHS criteria

Conclusions:

Under the experimental conditions employed and based on the above results, it is
concluded that the acute dermal median lethal dose (LD50) of test item prop-2-yn-1-yl
1H-imidazole-1-carboxylate in Sprague Dawley rats is > 2000 mg/kg body weight and
classified as “Category 5 / Unclassified” (2000 < ATE ≤ 5000 mg/kg body weight)
according to the Globally Harmonized System (GHS) of Classification.

Executive summary:

The test item prop-2-yn-1-yl 1H- imidazole-1-carboxylate was evaluated for Acute Dermal Toxicity in Sprague Dawley Rats.

The study was performed in two phases i.e. range finding study and main study. Range finding study was performed with three female rats (single animal per dose) and main study was performed with two female rats.

The required quantity of the test item was applied as uniform film over an area of approximately 10% of the total body surface. The test item was moistened with 0.5 mL of distilled water to form a thin paste using glass rod and was held on to the applied surface by covering with cotton gauze dressing and wrapped with non- irritating adhesive tape and finally the application site was wrapped using semi-occlusive crepe bandage. The contact period of test item was 24 hours.

No clinical signs and mortalities were observed at the dose level of 200 mg/kg body weight in range finding study. Further one animal was dosed
at 1000 mg/kg body weight. No clinical signs and mortalities were observed at the dose level of 1000 mg/kg body weight in range finding study. Next one animal was dosed at 2000 mg/kg body weight. No clinical signs and mortalities were observed at the dose level of 2000 mg/kg body weight in range finding study. Hence, during main study, two animals were administered with the same dose level of 2000 mg/kg body weight. No clinical signs and mortalities were observed at the dose level of 2000 mg/kg body weight. No mortality was observed at any of the dosed steps. Hence, no further testing was carried out.

No mortality and clinical signs were noted.
No skin reactions were observed at 24, 48 and 72 hours after patch removal.
No treatment related changes in body weight and percent change in body weight with respect to day 1 were noted. Normal increase in body weights were noted during the observation period. No treatment related gross pathological changes were noted in any of the dosed animals (range finding study and main study) during necropsy.