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Toxicological information

Dermal absorption

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dermal absorption
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: This study followed OECD 427 protocol with no major deviations and was conducted under GLP. Study is used in weight of evidence/read across approach

Data source

Reference Type:
study report

Materials and methods

Test guideline
according to guideline
OECD Guideline 428 (Skin Absorption: In Vitro Method)
GLP compliance:

Test material

Constituent 1
Chemical structure
Reference substance name:
Phenol, dodecyl-, branched
EC Number:
EC Name:
Phenol, dodecyl-, branched
Cas Number:
Molecular formula:
C15H24O to C21H36O
Phenol, alkyl branched (species comprising decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl substituents)
Test material form:
liquid: viscous
Details on test material:
- Name of test material (as cited in study report): CASRN 74499-35-7
- Substance type: Pure active substance
- Physical state: liquid
C14 ring label

Test animals

other: RCCHan:WIST (SPF): Wistar

Administration / exposure

unchanged (no vehicle)
Duration of exposure:
6 hours
0.01, 0.1, 1 mg/10 cm2
No. of animals per group:
4 (total of 16)
Control animals:

Results and discussion

Signs and symptoms of toxicity:
no effects
Dermal irritation:
no effects

Any other information on results incl. tables

After 6 hours of exposure, 4.4%, 6.9%, and 3.9% of the low, middle, and high dose were dermally absorbed. Most of the remaining applied dose (58-62%) was dislodged from the application site either by being washed off after the exposure period or recovered in the extracts of the covers and O-rings. At 72 hours, systemic absorption increased to 15.7%, 17.3% and 13.4% of the applied low, middle, and high dose, respectively. Consequently the radioactivity recovered at the application site, skin stripping and remaining treated skin after skin stripping, decreased with time indicating that the residues in skin were very slowly absorbed. Most of the radioactivity at the application site was recovered in lower skin levels (tape strips III – VII and remaining treated skin) i.e. 21.7-23.1% at 6 hours, 13.3-17.0% at 24 hours, 14.6-18.2% at 48 hours and 10.7-16.2% at 72 hours. This amount in the lower skin levels of the application site has to be considered as a depot for absorption and therefore the maximum systemic absorption totally accounted for 29.8% of the low dose, 33.6% of the middle dose, and 24.2% of the high dose.

Concentrations in blood and plasma remained low for all doses. When measurable, concentrations in blood and/or plasma stayed relatively constant with time. Concentrations in plasma were higher than concentrations in blood indicating that test item related material is mostly associated with the plasma fraction of the blood.

The systemically absorbed test item was excreted mainly via feces. After 3 days, 10.05% of the low dose, 11.67% of the mid dose and 9.10% of the high dose were excreted with the feces whereas 1.14% of the low dose, 1.00% of the mid dose and 0.81% of the high dose was excreted with the urine. In the cage wash, 0.10%, 0.15% and 0.12% of the applied low, mid and high dose were recovered, respectively. Three days after start of exposure, 4.45% of the low dose, 4.51% of the mid dose and 3.40% of the high dose were still remaining in the animals (i.e. carcass, whole blood, gastrointestinal tract, and non-treated skin).

Applicant's summary and conclusion

[14C]-TPP was systemically absorbed to the same moderate extent for all dose levels tested, i.e. 24-34% (29.8% of the low dose, 33.6% of the middle dose, and 24.2% of the high dose). The calculated penetration rates increased in a proportional fashion with the dose levels.