Registration Dossier

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
dermal absorption in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 428 (Skin Absorption: In Vitro Method)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Radiolabelling:
yes
Species:
human
Sex:
not specified
Details on test animals or test system and environmental conditions:
Human skin membranes were prepared from frozen skin samples, present at TNO
Quality of Life. Human skin (derived from abdomen and/or breast) was obtained from
six donors, directly after surgery.
Donor 1: TNA# 44/09, born in 1961, arrival at TNO on 20 November 2009
Donor 2: TNA 45/09, born in 1968, arrival at TNO on 10 December 2009
Donor 3: TNA 01/10, born in 1954, arrival at TNO on 14 January 2010
Donor 4: TNA 02/10, born in 1969, arrival at TNO on 15 January 2010
Donor 5: TNA 06/10, born in 1983, arrival at TNO on 28 January 2010
Donor 6: TNA 07/10, born in 1973, arrival at TNO on 29 January 2010
The transportation of the skin to the laboratory was carried out as soon as possible after
dissection, while the skin was placed in a plastic container that was kept on ice.
Subcutaneous fat was removed and the skin was stored in aluminium foil at < −18 °C
until use. The skin of donors 2, 3 and 4 was stored overnight at 2 – 10 °C before
subcutaneous fat was removed. Informed consent was provided by all donors.
Upon thawing of the skin, human skin was cut to a thickness of ca 400 μm using a
Dermatome (25 mm, Nouvag GmbH, Germany). The thickness of all skin preparations
was measured with a digimatic micrometer (Mitutoyo Corporation, Japan).
Type of coverage:
other: not applicable
Vehicle:
other: cream rinse formulation (test substance content: 5%) and cationic O/W cream (test substance content: 3%)
Duration of exposure:
30 minutes for the rinse-off product and 24 hours for the leave-on product
Doses:
C22-ATQ was applied to the skin surface in two relevant formulations under anticipated in use conditions as follows:

Test group Group size Product Concentration Dose a.i. (microg/cm²) Exposure time
A 18 Cream rinse (rinse off) 5.01 % (w/w) 279 +/- 87 30 min.
B 18 Cationic O/W Cream (leave on) 3.01 % (w/w) 153 +/- 37 24 h

Approximately 3.2 mg of the formulation was applied on each skin membrane (0.64 cm2), i.e. ca 5 mg/cm².
No. of animals per group:
Three skin membranes from six donors in each test group.
Control animals:
no
Details on in vitro test system (if applicable):
See below
Total recovery:
See below
Dose:
279
Parameter:
percentage
Absorption:
0.2 %
Remarks on result:
other: total
Remarks:
Formulation A (5% Cream rinse)
Dose:
153
Parameter:
percentage
Absorption:
0.16 %
Remarks on result:
other: total
Remarks:
Formulation B (3 % Cationic O/W Cream)

Results

Integrity of skin membranes

Prior to the determination of the percutaneous absorption of C22-ATQ, the permeation

coefficient (Kp) for tritiated water was determined.

Skin membranes with a Kp value below the cut-off value of 2.5 ×10-3 cm/h (human)

were selected for the study. All replicates of donor 4 were found to have (slightly)

higher Kp values for tritiated water than the cut-off value. Since at that time, these

membranes could not be replaced, these cells were taken along anyway. The individual

data of the absorption of tritiated water through the skin preparations are given in

Appendix 1.

Percutaneous absorption of C22-ATQ

Formulation A (5% Cream rinse):

The mean absorption of C22-ATQ from the 5% cream rinse formulation into the

receptor fluid after 24 hours was 0.063 microg/cm², representing 0.02% of the applied

dose. The mean maximal flux for the absorption of C22-ATQ was 0.013 microg/cm²h.

The lag time was 0.5 h (Table 1, Appendices 4 and 6). A total of 15 replicates from five

donors were considered for the calculations of mean values.

The mean total absorption, defined as the compound-related radioactivity present in the

receptor fluid, the receptor compartment wash and the skin membranes (excluding tape

strips) was 0.20 ± 0.20 % of the dose applied (Appendix 6).

The mean recovery of C22-ATQ was 91.6 ± 15.9 % (Appendix 6).

Formulation B (3 % Cationic O/W Cream)

The mean absorption of C22-ATQ from the 3% Cationic O/W Cream into the receptor

fluid after 24 hours was 0.086 microg/cm², representing 0.06 % of the applied dose. The

mean maximal flux for the absorption of C22-ATQ was 0.004 microg/cm²h. The lag time

was 2.6 h (Table I, Appendices 4 and 6). A total of 14 replicates from five donors were

considered for the calculations of mean values.

The mean total absorption was 0.16 ± 0.08 % of the applied dose. The mean recovery of

C22-ATQ was 102.8 ± 11.8 % (Appendix 6).

For some individual values, the mean recovery did not meet the OECD criteria of 100 ±

10 % or the criteria as set by the SCCP (i.e. ranging from 85 to 115 %). Differences are

most likely caused by the technical difficulties that go together with the adequate

application of small amounts of formulation. However, since the dermal absorption data

are comparable to the other replicates with appropriate recovery levels, the data were

not excluded from the calculations of the mean values.

Conclusions:
The dermal penetration was investigated according to guideline OECD 428 ( Skin Adsorption; In vitro method). When 5% formulation of behenyl trimethyl ammonium chloride was applied for 30 min on human skin the mean total absorption was 0.20 +/-0.20%. When 3% formulation of behenyl trimethyl ammonium chloride (major component of the registration substance) was applied for 24 h on human skin the mean total absorption was 0.16+/-0.08%.
Executive summary:

The dermal penetration was investigated according to guideline OECD 428 ( Skin Adsorption; In vitro method). When 3.2 mg of 5% formulation of behenyl trimethyl ammonium chloride was applied for 30 min on human skin membrane (i.e. ca 5 mg/cm2) the mean total absorption was 0.20 +/-0.20%. When the same amount of 3% formulation of behenyl trimethyl ammonium chloride (major component of the registration substance) was applied for 24 h the mean total absorption was 0.16+/-0.08%.

Description of key information

The dermal penetration was investigated according to guideline OECD 428 ( Skin Adsorption; In vitro method). When 3.2 mg of 5% formulation of behenyl trimethyl ammonium chloride was applied for 30 min on human skin membrane (i.e. ca 5 mg/cm2) the mean total absorption was 0.20 +/-0.20%. When the same amount of 3% formulation of behenyl trimethyl ammonium chloride (major component of the registration substance) was applied for 24 h the mean total absorption was 0.16+/-0.08%.

Key value for chemical safety assessment

Additional information