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The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

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:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Publication with detailed documentation, used for assessment

Data source

Reference
Reference Type:
publication
Title:
In Vitro Human Skin Penetration of Geraniol and Citronellol
Author:
Gilpin S., Hui X., Maibach H.
Year:
2010
Bibliographic source:
Dermatitis, Vol 21, No 1 (January/February): pp 41-48

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 428 (Skin Absorption: In Vitro Method)
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Citronellol
EC Number:
203-375-0
EC Name:
Citronellol
Cas Number:
106-22-9
Molecular formula:
C10H20O
IUPAC Name:
3,7-dimethyloct-6-en-1-ol
Test material form:
other: aqueous solution
Details on test material:
- Name of test material (as cited in study report): citronellol (1-14C)
- Physical state: aqueous solution
- Analytical purity: 99%
- Specific activity (if radiolabelling): 52 mCi/mmol
Radiolabelling:
yes

Test animals

Species:
human
Strain:
other: not applicable
Sex:
not specified

Administration / exposure

Type of coverage:
occlusive
Vehicle:
other: DEP and ethanol (3:1)
Duration of exposure:
24 hours
Doses:
2% and 5% citronellol (weight per volume). 20 µl dose solution of approximately 0.5 µCi radioactivity applied.
No. of animals per group:
Skin was obtained from four donors
Details on in vitro test system (if applicable):
SKIN PREPARATION
- Source of skin: Department of Pathology at the University of California,San Francisco
- Type of skin: Human cadaver skin without obvious signs of skin disease
- Preparative technique: dermatomed with a Padgett ElectroDermatome
- Thickness of skin (in µm): approx. 400
- Membrane integrity check: checked visually, transepidermal water loss (TEWL): TEWL values of less than 15 g/m2h were considered acceptable
- Storage conditions: obtained within 24 hours of donor death, immediately placed in aluminum foil and amply sealed and stored at ~ 20°C until used.


PRINCIPLES OF ASSAY
- Diffusion cell: continuous-flow diffusion cell (item LG-1084, Laboratory Glass Apparatus, Inc., Berkeley, CA)
- Receptor fluid: 6% polyethylene glycol and sodium phosphate-buffered saline (pH=7.4)
- Test temperature: approx. 32°C skin surface temp.
- Occlusion: Yes (plastic chamber with a 2.2 cm2 cotton pad, sealed with Parafilm M Laboratory Wrapping Film and a layer of adhesive tape)

Results and discussion

Percutaneous absorptionopen allclose all
Dose:
2%
Parameter:
percentage
Absorption:
3.8 %
Remarks on result:
other: 24 hours
Dose:
5%
Parameter:
percentage
Absorption:
4.7 %
Remarks on result:
other: 24 hours

Any other information on results incl. tables

After 24 hours, citronellal had relatively low skin absorption rates. Dose recoveries for all compartments measured are given in a graph only. However, key information for the assessment of bioavailability and total recovery are given as table:

Mass Balance and Percutaneous Absorption of Citronellol by Human Skin in Vitro

Compound Removed dose after 24h [%]* Penetrated dose absorbed after 24h [%]*
Citronellol 2% 86.3+/-5.2 3.8+/-2.1
Citronellol 5% 81.6+/-3.8 4.7+/-1.9

*Values are means +/- SD. Number of determinations = 12.

Based on the text given in the results section, the following has been reported by the authors:

Increasing concentration increased absorption; Recovery for fragrance materials was good; Most of the dose was recovered in the skin washes; Recovery was much less for all other compartments; the cover compartments for 2% and 5% citronellol had the next highest dose recoveries (15.5% ± 3.9% and 10.7% ± 0.9%, respectively), followed by the tape strips (6.1%± 4.3% and 4.3% ± 0.3%, respectively). Examination of the time variable in box plots for the receptor fluid collection points showed a linear increase in the amounts of citronellol that penetrated the skin even though the overall values of absorption were quite small.

 

Applicant's summary and conclusion