2-Ethylhexyl trans-4-methoxycinnamate

Dermal absorption

Administrative data

Endpoint:

dermal absorption in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Study was conducted according to an equivalent of OECD guideline 428, but not under GLP conditions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1979

Report date:

1979

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 428 (Skin Absorption: In Vitro Method)

Deviations:

yes

GLP compliance:

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
- Specific activity (if radiolabelling): 2.55 uCi/mg, 0.86 uCi/mg and 0.26 uCi/mg

Radiolabelling:

yes

Remarks:

14C

Test animals

Species:

other: naked rat

Strain:

not specified

Sex:

not specified

Administration / exposure

Type of coverage:

other: Closed system

Vehicle:

other: Carbitol

Duration of exposure:

1, 6, 16 and 24 hours

Doses:

- Nominal doses: 1, 3 and 10 % in carbitol
- Actual doses: 120, 360, 1200 µg substance/cm² respectively

Control animals:

no

Results and discussion

Percutaneous absorption

Percutaneous absorption 1

Dose:

1 % in carbitol

Parameter:

percentage

Absorption:

1.7 %

Remarks on result:

other: 1 hr

Remarks:

Based on amount of test material in stripped skin and chamber liquid

Percutaneous absorption 2

Dose:

1 % in carbitol

Parameter:

percentage

Absorption:

21.3 %

Remarks on result:

other: 6 hrs

Remarks:

Based on amount of test material in stripped skin and chamber liquid

Percutaneous absorption 3

Dose:

1 % in carbitol

Parameter:

percentage

Absorption:

39.7 %

Remarks on result:

other: 16 hrs

Remarks:

Based on amount of test material in stripped skin and chamber liquid

Percutaneous absorption 4

Dose:

3 % in carbitol

Parameter:

percentage

Absorption:

1.9 %

Remarks on result:

other: 1 hr

Remarks:

Based on amount of test material in stripped skin and chamber liquid

Percutaneous absorption 5

Dose:

3 % in carbitol

Parameter:

percentage

Absorption:

13.6 %

Remarks on result:

other: 6 hrs

Remarks:

Based on amount of test material in stripped skin and chamber liquid

Percutaneous absorption 6

Dose:

3 % in carbitol

Parameter:

percentage

Absorption:

33.2 %

Remarks on result:

other: 16 hrs

Remarks:

Based on amount of test material in stripped skin and chamber liquid

Percutaneous absorption 7

Dose:

10 % in carbitol

Parameter:

percentage

Absorption:

2.1 %

Remarks on result:

other: 1 hr

Remarks:

Based on amount of test material in stripped skin and chamber liquid

Percutaneous absorption 8

Dose:

10 % in carbitol

Parameter:

percentage

Absorption:

12.8 %

Remarks on result:

other: 6 hrs

Remarks:

Based on amount of test material in stripped skin and chamber liquid

Percutaneous absorption 9

Dose:

10 % in carbitol

Parameter:

percentage

Absorption:

22.8 %

Remarks on result:

other: 16 hrs

Remarks:

Based on amount of test material in stripped skin and chamber liquid

Any other information on results incl. tables

Percentage of substance absorbed after 24 hrs:

1 % in carbitol: 44.3 %

3 % in carbitol: 35.6 %

10 % in carbitol: 22.7 %

About 70 - 90 % of the applied dose of Ethylhexyl Methoxycinnamate was found on the skin surface during the first 6 hours after application

The amount recovered from the stratum corneum was low and reached its maximum 24 hours after application. The steady state was attained within 6 hours.

The portion of Ethylhexyl Methoxycinnamate found in the stripped skin increased to its maximum within 16 hours. Lower levels of the test material were found 24 hours after application.

A significant part of the applied dose was found in the chamber liquid (7 - 17 %) after longer times of exposure.

Applicant's summary and conclusion

Conclusions:

In an in vitro system using naked rat skin, the skin penetration potential and resorption capacity of Ethylhexyl Methoxycinnamate were significant after longer times of exposure, based on the high amount of Ethylhexyl Methoxycinnamate found in the stripped skin, the low levels in the stratum corneum and the amount of activity recovered from the chamber liquid.

Executive summary:

Skin penetrating potential of Ethylhexyl Methoxycinnamate in naked rat skin was determined in a study using an in vitro system. The study was performed according to an equivalent of OECD guideline 428. Three concentrations of Ethylhexyl Methoxycinnamate in carbitol (1, 3 and 10 %) were applied and skin absorption rates were determined by the activity of the 14C-labelled test article.

It was found that the higher amount of Ethylhexyl Methoxycinnamate is absorbed into the upper layer of the skin (stripped skin). The low levels in the stratum corneum and the amount of activity recovered from the chamber liquid indicate significant penetration and resorption capacities of Ethylhexyl Methoxycinnamate through the intact skin of the naked rat after longer times of exposure.