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Toxicological information

Dermal absorption

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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:
OECD Guideline 428 (Skin Absorption: In Vitro Method)
Deviations:
yes
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
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 absorptionopen allclose all
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
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
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
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
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
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
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
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
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.