Alcohols, C12-13, ethoxylated

Dermal absorption

Administrative data

Endpoint:

dermal absorption in vivo

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Expert judgement combined with experimental data.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

The absorption, distribution and excretion of alkyl polyethoxylates by rats and humans.

Author:

Drotman, R.B.

Year:

1980

Bibliographic source:

Tox. Appl. Pharm. 52:38-44

Reference 2

Reference Type:

publication

Title:

In vivo percutaneous absorption of polyoxyethylene lauryl ether surfactants in hairless mice.

Author:

Nishiyama, T. et al.

Year:

1983

Bibliographic source:

J. Soc. Cosmet. Chem. 34:263–271

Materials and methods

Principles of method if other than guideline:

No guideline exists for this type of appraisal.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Dodecan-1-ol, ethoxylated

EC Number:

500-002-6

EC Name:

Dodecan-1-ol, ethoxylated

Cas Number:

9002-92-0

Molecular formula:

not applicable

IUPAC Name:

Dodecan-1-ol, ethoxylated

Constituent 2

Reference substance name:

C12AE6

IUPAC Name:

C12AE6

Details on test material:

not applicable

Radiolabelling:

other: partly

Test animals

Species:

other: rat and human

Administration / exposure

Type of coverage:

other: Various, for details see "any other information on materials and methods"

Vehicle:

other: Various, for details see "any other information on materials and methods"

Duration of exposure:

Various, for details see "any other information on materials and methods"

Doses:

Various, for details see "any other information on materials and methods"

No. of animals per group:

Various, for details see "any other information on materials and methods"

Results and discussion

Any other information on results incl. tables

It was shown that the amount absorbed increased linearly with time. In the case of LAE containing ethylene oxide units larger than 2 moles, the LAE absorbed percutaneously was rapidly metabolized to CO2 and excreted in expired air. Therefore, the rate of percutaneous absorption could be calculated from the rare of expiratory excretion. This result coincided with the amount obtained from the slope of the percutaneous absorption curve as a function of time.

Moreover it could be shown that LAE-1 and LAE-2.6 penetrate the skin readily while LAE-10 is barely absorbed.

Most of the activity applied to human skin was removed by cleaning the application site with alcohol soaked gauze (i.e., 73.9% in subject 1; 87.5% in subject 2) and less than 2% (i.e., 1.82% in subject 1; 1.03% in subject 2) was detected in the urine. No radioactivity was found in the faeces or in form of CO2. Radioactivity in the blood was barely detectable. In subject 2, it was equivalent to 0.14 µg/g at 8 hours, 0.02 µg/g at 12 hours and 0.01 µg/g at 24 hours indicating that the vast majority of dermally absorbed AE was absorbed within the first 24 hours. The total recovery of radioactivity was 82.4% for subject 1 and 94.7% for subject 2. Urinary excretion was the primary route of elimination following dermal absorption.

Applicant's summary and conclusion

Conclusions:

The dermal penetration rate for alcohol ethoxylates was calculated on the basis of a dermal penetration study with 14C-labelled C12AE6 in human volunteers and assumes –conservatively- 2% absorption within the first 24 hours following dermal application.