2-Ethylhexyl trans-4-methoxycinnamate

Repeated dose toxicity: dermal

Administrative data

Endpoint:

short-term repeated dose toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

May 1979 - August 1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study was not conducted under GLP and according to an OECD guideline. However, the experimental design resembles OECD guideline 410 and the report is well documented.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1980

Report date:

1980

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)

Deviations:

not applicable

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-ethylhexyl 4-methoxycinnamate

EC Number:

226-775-7

EC Name:

2-ethylhexyl 4-methoxycinnamate

Cas Number:

83834-59-7

Molecular formula:

C18H26O3

IUPAC Name:

2-​Propenoic acid, 3-​(4-​methoxyphenyl)​-​, 2-​ethylhexyl ester, (2E)​-

Details on test material:

- Name of test material (as cited in study report): Ethylhexyl Methoxycinnamate
- Physical state: Liquid (oily)
- Stability under test conditions: Stable for up to 3 months
- Storage condition of test material: Room temperature, protected from light

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Bantin & Kingman Ltd., Grimston, Aldbrough, Hull
- Weight at study initiation:
Male: 181 - 232 g
Female: 158 - 196 g
- Housing: Individually, in solid bottomed plastic cages
- Diet (e.g. ad libitum): Ad libitum, pelleted
- Water (e.g. ad libitum): Ad libitum, water bottles
- Acclimation period: 12 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 - 25
- Humidity (%): 40 - 60
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on exposure:

TEST SITE
- Area of exposure: Back and flanks
- Type of wrap if used: Aluminium foil with a strip of impermeable plaster
- Time intervals for shavings or clipplings: 24 hours prior to treatment

TEST MATERIAL
- Amount(s) applied (volume or weight with unit):
Group 1: 0 mL/kg bw/day
Group 2: 0.5 mL/kg bw/day (= 500 mg/kg/day)
Group 3: 1.5 mL/kg bw/day (= 1500 mg/kg/day)
Group 4: 5.0 mL/kg bw/day (= 5000 mg/kg/day)
- Concentration (if solution): 1000 mg/mL (specific gravity: 1.011)
- Constant concentration used: Yes

Analytical verification of doses or concentrations:

no

Details on analytical verification of doses or concentrations:

Not relevant

Duration of treatment / exposure:

28 days, 6 hours contact period/day

Frequency of treatment:

Once daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

500 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

1 500 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

5 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

Intact skin: 5
Abraded skin: 5

Control animals:

yes

Details on study design:

- Dose selection rationale: selected after examination of data from a 7 day dose range-finding study
- Section schedule rationale (if not random): Animals were allocated randomly throughout the whole study

Positive control:

No data

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily
- Cage side observations:
Signs of toxicity
Ill health
Behavioural change

DERMAL IRRITATION (if dermal study): Yes
- Time schedule for examinations: Daily
Erythema and oedema were scored on a scale from 0 - 4.
All-or-nothing scale was used for skin reactions concerning desquamation, fissuring and atonia.

BODY WEIGHT: Yes
- Time schedule for examinations: prior to treatment on first day and thereafter on every Monday and Thursday

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: Pre-dose and pre-termination during week 4
- Dose groups that were examined: All animals

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Prior to commencement of therapy and during week 4 of study
- Anaesthetic used for blood collection: Yes (diethyl ether)
- Animals fasted: Yes, approx. 16 hours
- How many animals: All animals
- Parameters checked:
Haemoglobin (Hb)
Packed cell volume (PCV)
Red blood cell count (RBC)
Mean cell haemoglobin (MCH)
Mean cell volume (MCV)
Mean cell haemoglobin concentration (MCHC)
Total white blood cell count (WBC)
Differential white blood cell count

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Prior to commencement of therapy and during week 4 of study
- Animals fasted: No data
- How many animals: All animals
- Parameters checked:
glucose
blood urea nitrogen (BUN)
glutamate-oxaloacetate transaminase activity (GOT)
glutamate-pyruvate transaminase activity (GPT)
alkaline phosphatase activity (Alk. P)
sodium ions
calcium ions
potassium ions
total protein
albumin
albumin/globulin ratio (A/G ratio)

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
Organ weigths: adrenals, brain, heart, kidneys, liver, ovaries, pituitary, testes, thyroids (with parathyroids)

HISTOPATHOLOGY: Yes
Following tissues:
adrenals
aorta (arch and anterior abdominal)
brain
caecum
colon
duodenum
ep ididymus
eye and optic nerve
heart
ileum
Jejunum
kidneys
liver
lungs
lymph nodes (mandibular and mesenteric)
skeletal muscle (quadriceps)
all unusual lesions
oesophagus
ovaries
pancreas
pituitary
prostate
rib and bone marrow
sciatic nerve
skin and mammary gland
spinal cord (lumbar region)
spleen
stomach
salivary gland (submaxillary)
t est es
trachea
treated and untreated skin
thytnus
thyroids
tongue
urinary bladder
uterus (corpus and cervix)
adrenals
aorta (arch and anterior abdominal)
brain
caecum
colon
duodenum
ep ididymus
eye and optic nerve
heart
ileum
Jejunum
kidneys
liver
lungs
lymph nodes (mandibular and mesenteric)
skeletal muscle (quadriceps)
all unusual lesions
oesophagus
ovaries
pancreas
pituitary
prostate
rib and bone marrow
sciatic nerve
skin and mammary gland
spinal cord (lumbar region)
spleen
stomach
salivary gland (submaxillary)
testes
trachea
treated and untreated skin
thytnus
thyroids
tongue
urinary bladder
uterus (corpus and cervix)

Statistics:

Group mean values and standard deviations

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Dermal irritation:

effects observed, treatment-related

Description (incidence and severity):

Irritation of the skin at the application site was first noted prior to the third application. The severity of reaction was most marked in group 4 (highest dose) animals and in particluar the female animals. This erythema and oedema was accompanied by desquamation of the application site. In general the skin reactions noted in groups 2 and 3 appeared mild (lower dose groups) and little irritation was noted in control group 1.
The irritation reached a maximum at the end of the second week and then regressed. The skin appeared normal in all treated animals at termination, with the exception of one male animal in the highest dose group.
The reactions indicate that the test article is a low grade irritant under the experimental conditions.

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not examined

Effect levels

Key result

Dose descriptor:

NOAEL

Effect level:

5 000 mg/kg bw/day (actual dose received)

Sex:

male/female

Basis for effect level:

other: overall effects

Target system / organ toxicity

Key result

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

The skin irritation reactions indicate that Ethylhexyl Methoxycinnamate is a low grade irritant under the experimental conditions. No evidence of any systemic toxicity by Ethylhexyl Methoxycinnamate was demonstrated. A NOAEL of 5000 mg/kg bw/day was established and the substance does not need to be classified as toxic after repeated exposure according to the criteria outlined in Annex I of 1272/2008/EC.

Executive summary:

Three groups of rats, each containing 5 male and 5 female animals with intact skin and 5 male and 5 female animals with abraded skin were treated by topical application with test article Ethylhexyl Methoxycinnamate at levels of 500, 1500 and 5000 mg/kg bw/day for 28 consecutive days. In addition a control group of 5 male and 5 female animals with intact skin and 5 male and 5 female animals with abraded skin was given a similar topical application of distilled water at a dose level of 5000 mg/kg bw/day for 28 days.

No animals died during the observation period in any group. No overt signs of toxicity were apparent in any treated group or control group during the observation period. No effect on body weight gain was apparent in any treated group compared with the control groups. The skin reactions observed suggest the test article is a low grade irritant under the experimental conditions used. No ocular defects related to treatment could be detected during an ophthalmoscopic examination at week 4. No treatment-induced effects were apparent in the haematology and blood chemistry parameters measured. No treatment related changes in individual organ weights or organ/body weight ratios were apparent. No evidence of systemic toxicity was noted at necropsy in any of the tissues and organs evaluated. Histological evaluation of the skin sites revealed a low grade epidermal proliferation in all groups.The degree of epidermal change tended to be dose-related, and males tended to show more epidermal change than females. There was no appreciable difference between intact and abraded skin sites, and no significant dermal inflammatory or fibrotic responses were seen in any rat.

Overall, a minimal to moderate epidermal proliferation in the absence of significant dermal changes suggested that the test article was a relatively low grade irritant under the prevailing experimental conditions. There was no evidence of systemic toxicity histologically in any of the other organs or tissues examined. A NOAEL of 5000 mg/kg bw/day was established and the substance does not need to be classified as toxic after repeated exposure according to the criteria outlined in Annex I of 1272/2008/EC.