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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study in compliance with international guidelines
Reference:
Composition 0
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
GLP compliance:
yes
Type of study:
mouse local lymphnode assay (LLNA)
Test material information:
Composition 1
Species:
mouse
Strain:
other: CBA/CaBkl and CBA/CruBR
Sex:
female
Details on test animals and environmental conditions:
Two female CBA/Ca (CBA/CaBkI) strain mice were supplied by B & K Universal Ltd, Hull, UK and seventeen female CBA/Ca (CBA/Ca CruBR) strain mice were supplied by Charles River UK Limited, Margate, Kent, UK. On receipt the animals were randomly allocated to cages. The animals were nulliparous and non-pregnant. After an acclimatisation period of at least five days the animals were selected at random and given a number unique within the study by indelible ink-marking on the tail and a number written on a cage card. At the start of the study the animals were in the weight range of 15 to 23 g, and were eight to twelve weeks old.
The animals were individually housed in suspended solid-floor polypropylene cages furnished with softwood woodflakes. Free access to mains tap water and food (Certified Rat and Mouse Diet) was allowed throughout the study.
The temperature and relative humidity were controlled to remain within target ranges of 19 to 25°C and 30 to 70%, respectively. Any occasional deviations from these targets were considered not to have affected the purpose or integrity of the study. The rate of air exchange was approximately fifteen changes per hour and the lighting was controlled by a time switch to give twelve hours continuous light (06.00 to 18.00) and twelve hours darkness.
Vehicle:
other: the test item was used undilited and reshly prepared in dimethyl formamide.
Concentration:
Preliminary test: Three mice were treated by daily application of 25 µl of the undiluted test material or the test material at concentrations of 50% or 25% v/v in dimethyl formamide, to the dorsal surface of each ear for up to three consecutive days (Days 1, 2, 3).
Main test: Groups of four mice were treated with the test material at concentrations of 5%, 10% or 25% v/v in dimethyl formamide.
No. of animals per dose:
main test: 4 mouse per dose
Details on study design:
Main test: Groups of four mice were treated with the test material at concentrations of 5%, 10% or 25% v/v in dimethyl formamide. The preliminary screening test suggested that the test material would not produce systemic toxicity or excessive local irritation at the highest suitable concentration. The mice were treated by daily application of 25 µl of the appropriate concentration of the test material to the dorsal surface of each ear for three consecutive days (Days 1, 2, 3). The test material formulation was administered using an automatic micropipette and spread over the dorsal surface of the ear using the tip of the pipette.
A further group of four mice received the vehicle alone in the same manner.
Five days following the first topical application of the test material (Day 6) all mice were injected via the tall vein with 250 µl of phosphate buffered saline (PBS) containing 3H-methyl thymidine (3HTdr: 80 µCi/ml, specific activity 2.0 Ci/mmol, GE Healthcare UK Ltd) giving a total of 20 µCi to each mouse.
Termination: Five hours following the administration of 3HTdR all mice were killed by carbon dioxide asphyxiation. The draining auricular lymph nodes from the four mice were excised and pooled for each experimental group. For each group I ml of PBS was added to the pooled lymph nodes.
Determination of 3HTdR Incorporation: After approximately eighteen hours incubation at approximately 4°C, the precipitates were recovered by centrifugation at 2100 rpm (approximately 450 g) for ten minutes, resuspended in 1 ml of TCA and transferred to 10 ml of scintillation fluid (Optiphase Trisafet). 3HTdR incorporation was measured by p-scintillation counting.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
not applicable
Positive control results:
hexyl cinnamic aldehyde was cisidered to be a sensitizer under the condition of the test.
Parameter:
SI
Remarks on result:
other: see Remark
Remarks:
Concentration (%v/v) in dimethyl formaldehyde Stimulation index Result vehicle na na 5 1.06 negative 10 1.92 negative 25 1.20 negative
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: see Remark
Remarks:
Concentration (%v/v) in dimethyl formaldehyde DPM vehicle 3765.09 5 3976.13 10 7231.61 25 4523.35

Individual clinical observation and mortality data for test and control animals were redorded.

There were no death. No signs of systemic toxicity were noted in the test or control animals during the test

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test material was considered to be a non-sensitizer under the conditions of the test,
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

The skin sensitizing potential of the test item was evaluated in one LLNA study. The LLNA study was conducted both according to OECD Guideline No. 429 and to Good Laboratory Practices (GLP) therefore the study has been consiedered a key study for this endpoint.

 


Migrated from Short description of key information:
The test material did not demonstrate evidence of skin sensitization potential in the Mouse local lymphnode assay (LLNA).

Justification for selection of skin sensitisation endpoint:
GLP study in compliance with international guidelines

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

The available in vivo study indicates that the notifiable substance is not sensitizing to skin. Thus, the data are conclusive but not sufficient for classification for skin sensitization.

No data is available to address respiratory sensitisation. As a result, the substance does not meet the criteria for classification according to Regulation (EC) No 1272/2008.