7-methyl-3-methyleneocta-1,6-diene

Endpoint summary

Description of key information

Oral and dermal LD50 are higher than 5000 mg/kg bw in rats. Oral LD50 is higher than 3000 mg/kg bw in mice. 

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1972

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Old study with lack of details on test conditions but reliable for acute oral toxicity.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

yes

Remarks:

Lack of details on test conditions

Principles of method if other than guideline:

Not applicable

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Doses:

5 g/kg

No. of animals per sex per dose:

10 males

Control animals:

no

Key result

Sex:

male

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

test mat.

Rats experienced lethargy and urinary incontinence. One death occured overnight following treatment.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Oral LD50 of myrcene is higher than 5000 mg/kg bw.

Executive summary:

Acute oral toxicity study (limit test) similarly to OECD guideline 401 was conducted with test substance myrcene in 10 male rats. The test substance was administered undiluted through oral gavage at the single dose of 5000 mg/kg bw. Animals were observed daily for mortality during 14 days. Gross necropsy was performed in all survivors.

Rats experienced lethargy and urinary incontinence. One death occured overnight following treatment.

Therefore, oral LD50 of the test substance is higher than 5000 mg/kg bw.

Endpoint conclusion

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

No data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Old study conducted similarly to OECD Guideline 402 with minor deviations: few data about test substance and test conditions, skin was abraded.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

yes

Remarks:

Few data about test substance and test conditions, skin was abraded.

Principles of method if other than guideline:

Not applicable

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

yes

Species:

rabbit

Strain:

New Zealand White

Sex:

not specified

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 1.7 to 2.4 kg

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
The test substance was applied at 5 g/kg bw on clipped abraded abdominal skin. The animals were wrapped with binders of rubber dam, gauze and adhesive tap.
Folllowing exposure, the binders were removed and observations were made.

Duration of exposure:

24 hours

Doses:

5 g/kg bw

No. of animals per sex per dose:

10

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations: Animals were observed frequently for mortality for 14 days. Body weights were recorded at pre and post-treatment.
- Necropsy of survivors performed: Yes

Statistics:

None

Preliminary study:

Not applicable

Key result

Sex:

not specified

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality was observed.

Clinical signs:

other: No evidence of systemic toxicity. Signs of irritation were noted (see table 1).

Gross pathology:

No abnormalities were noted upon gross necropsy.

Other findings:

None

Table 1: signs of dermal irritation in rabbits following a 24-h exposure with myrcene

Observation day	Erythema	Edema
1	++ (8) + (2)	++ (9) + (1)
2	++ (5) + (5)	++ (5) + (5)
3	++ (3) + (6)	++ (3) + (6)
4	++ (1) + (7)	++ (2) + (6)
5	+ (5)	+ (4)
6	-	+ (2)
7	-	-
8	-	-
9	-	-
10	-	-
11	-	-
12	-	-
13	-	-
14	-	-

+ : slight ; ++ : moderate ; number in parentheses = number of animals showing sign

Table 2: bodyweights before and after treatment

Animal number	Pre-treatment (kg)	Post-treatment (kg)
1	2.0	1.9
2	1.7	1.8
3	1.9	2.0
4	2.0	1.9
5	2.4	2.4
6	2.0	2.0
7	1.8	1.8
8	2.1	2.0
9	2.2	2.1
10	2.2	2.2

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute dermal LD50 of myrcene was greater than 5 g/kg bw.

Executive summary:

In an acute dermal toxicity study performed similarly to OECD guideline 402, a group of 10 New Zealand White rabbits received a single dermal dose of myrcene at 5 g/kg on clipped abraded abdominal skin in occlusive conditions for 24 h. All animals were observed for mortality and skin reactions for 14 days. No mortality was observed. No changes in bodyweight related to treatment could be observed. No signs of systemic toxicity were observed. All animals showed slight to moderate erythema and edema during the first days after exposure that were completely reversed after 7 days.No abormalities were noted upon gross necropsy. Therefore, the acute dermal LD50 was greater than 5 g/kg bw.

Endpoint conclusion

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Additional information

One acute oral toxicity study was performed in rats at doses up to 11.39 g/kg bw where no mortality was found at any dose (Paumgartten, 1990a). In another acute oral toxicity study, no mortality was found in rats given myrcene at 5 g/kg bw (Moreno, 1972). In mice, no mortality was observed up to 3380 mg/kg bw (Paumgartten, 1990b).

In an acute dermal toxicity study performed in 10 rabbits, no mortality was found in rabbits at an applied dose of 5 g/kg bw (Moreno, 1972).

Justification for classification or non-classification

Oral and dermal LD50 are higher than 5000 mg/kg bw in rats and rabbits respectively therefore myrcene does not need to be classified according to Directive 67/548/EEC and CLP Regulation (EC) N° 1272/2008.