Reaction mass of stigmast-5-en-3-β-ol and stigmasta-5,22-dien-3-β-ol and (24R)-ergost-5-en-3β-ol

Skin sensitisation

Administrative data

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:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 442B (Skin Sensitization: Local Lymph Node Assay: BrdU-ELISA)

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA): BrdU-ELISA

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of (24R)-ergost-5-en-3β-ol and stigmast-5-en-3-β-ol and stigmasta-5,22-dien-3-β-ol

EC Number:

904-790-6

Molecular formula:

C28H48O; C29H50O; C29H48O

IUPAC Name:

Reaction mass of (24R)-ergost-5-en-3β-ol and stigmast-5-en-3-β-ol and stigmasta-5,22-dien-3-β-ol

In vivo test system

Test animals

Species:

mouse

Strain:

CBA:JN

Sex:

female

Details on test animals and environmental conditions:

Species and strain Mice, CBA/JN
Sex Females (nulliparous and non-pregnant)
Age 7 to 8 weeks old, 21 to 25 grams
Supplier Charles River Italia S.p.A., Calco (Lecco), Italy
Weight range at arrival 17 to 20 grams
Acclimatisation period At least 5 days
Animals per cage 5 during acclimatisation; 1/cage during the study
Housing Polysulfone solid bottomed cages measuring 35.5 × 23.5 × 19
cm with nesting material
Cage control Daily inspected and changed as necessary (at least
twice/week)
Water drinking water supplied to each cage via a water bottle
Water supply ad libitum
Diet 4 RF 21 (Mucedola S.r.l., Via G. Galilei, 4, 20019, Settimo
Milanese (MI) Italy)
Diet supply ad libitum throughout the study
Room lighting Artificial (fluorescent tubes), daily light/dark cycle of 12/12
hours
Air changes Approximately 15 to 20 air changes per hour
Temperature range 22 °C ± 2 °C
Relative humidity range 55 % ± 15 %

Study design: in vivo (LLNA)

Vehicle:

propylene glycol

Concentration:

In the main assay, the test item was topically administered at concentrations of 10, 5 and
2.5 % (w/w), in propylene glycol.
Five concentrations [10 (maximum feasible concentration), 5, 2.5, 1 and 0.5 % w/w in
acetone:olive oil 4:1 (v/v)] were tested in the preliminary phase.

Details on study design:

A solubility trial was performed in order to establish if acetone/olive oil 4:1 v/v could be used as vehicle.
At concentrations of 50, 25 and 10 % w/w in acetone/olive oil 4:1 v/v, no dosable prepara-
tions were obtained. Therefore, 3 further vehicles were tested: DMSO, PEG and propylene
glycol at the same concentrations. Results of this trial indicated propylene glycol as vehicle
with a maximum achievable concentration oh 10%.

Positive control substance(s):

other:

Results and discussion

In vivo (LLNA)

Results

Parameter:

SI

Value:

1.7

Test group / Remarks:

high dose group 10% w/w

Any other information on results incl. tables

Neither mortality nor clinical signs were recorded in animals treated at all dose levels investigated [10, 5 and 2.5 % (w/w)].
Changes in body weight observed during the study were within the expected range for this strain and age of animals.

A slight increase in cell proliferation of draining lymph nodes was observed in the high dose group [10 % (w/w)], with a Stimulation Index of 1.70. The other calculated indices (SI) were 1.42 and 1.20 respectively, at a low and medium dose group [2.5 % and 5 % (w/w)
respectively]. No correlation with the doses nor statistical significance was observed. The above results indicate that the test item may elicit a sensitisation response. However, due to the borderline positive response, the absence of a dose-response relationship and statistical
significance, the observed reaction is not sufficient to require classification.
In the group treated with the positive control item, a Stimulation Index of 3.28 was calculated.
As it was greater than 2, the study was regarded as valid.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

A slight increase in cell proliferation of draining lymph nodes was observed in the high
dose group [10 % (w/w)], with a Stimulation Index of 1.70. The other calculated indices
(SI) were 1.42 and 1.20 respectively, at a low and medium dose group [2.5 % and 5 % (w/w)
respectively]. No correlation with the doses nor statistical significance was observed. The
above results indicate that the test item may elicit a sensitisation response. However, due to
the borderline positive response, the absence of a dose-response relationship and statistical
significance, the observed reaction is not sufficient to require classification.