Registration Dossier

Administrative data

Endpoint:
dermal absorption in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-study according to OECD guideline

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 428 (Skin Absorption: In Vitro Method)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Radiolabelling:
no

Test animals

Species:
human
Strain:
other: not applicable
Sex:
female
Details on test animals and environmental conditions:
Skin was excised from the abdomen from three females aged 30, 43 and 48 years

Administration / exposure

Type of coverage:
other: covered
Vehicle:
unchanged (no vehicle)
Duration of exposure:
24 h
Doses:
- Actual doses: 30 µL
No. of animals per group:
not applicable
Control animals:
no
Details on in vitro test system (if applicable):
SKIN PREPARATION
- Source of skin: abdomen of three females
- Type of skin: abdomen
- Preparative technique: full-thickness skin
- Thickness of skin (in mm): 1520 - 2205 µm
- Membrane integrity check: caffeine as benchmark
- Storage conditions: -20°C

PRINCIPLES OF ASSAY
- Diffusion cell: Franz diffusion cells with a diffusion area of approximately 3 cm2
- Receptor fluid: none
- Solubility of test substance in receptor fluid: no
- Test temperature: 32 +/- °C
- Occlusion: covered with Parafilm
- Reference substance(s): caffeine

Results and discussion

Total recovery:
mean recovery: 104.5%
Percutaneous absorption
Dose:
30 µl
Parameter:
percentage
Absorption:
ca. 0.12 %
Remarks on result:
other: 24h
Remarks:
mean absorption
Conversion factor human vs. animal skin:
not applicable

Applicant's summary and conclusion

Conclusions:
In a GLP-study according to OECD test guideline 428, the dermal penetration of the registered substance was determined to be about 0.12%.
Executive summary:

The skin penetration of the registered substances was determined in a GLP-study according to OECD test guideline 428.

The HPLC method was successfully developed and validated with regard to method selectivity, linearity, accuracy and precision in the extraction medium employed for the penetration experiments (methanol). Furthermore, the test item has demonstrated good stability over the period of 24 hours at RT in methanol.

The content of PHC was determined in triplicate in the test solution and mean value was 109.4 %, which complies to the acceptance criteria of 100 ± 10 %.

The results from the extraction method have shown that methanol was suitable for performing the penetration experiments presenting recovery values which has ranged between 85.18 % to 104.43 % for samples with skin contact, which complies to the acceptance limit 100 ± 20 %.

The mass recovery calculations present amounts and percentages of compound which penetrated and remained in the donor compartment. The mean amount of the registered substance removed from the skin surface (skin wash) ranged from 84.55 % to 121.80 % of the dose applied. The mean recovery in the two first tape strips was 0.36 % during all performed experiments. In the further

18 tape strips a mean recovery of 0.46 % was documented. The mean absorbed dose of the substance,sum of the amounts found in the viable epidermis, dermis and filter, was 0.12 %. That means, most of the test substance remains at the skin surface, a small amount migrates into the Stratum corneum and an even smaller amount enters the deeper skin layers.

The mean Papp values measured for Caffeine in the present study for the human skins are in good agreement with Papp values determined for a variety of skin specimens from different donors under comparable conditions.