Registration Dossier

Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
5 November 2009- 11 November 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted to GLP in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Qualifier:
according to
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
GLP compliance:
yes (incl. certificate)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): dineodymium tricarbonate
- Substance type: extremely pale purple powder
- Physical state: solid
- Lot/batch No.: not provided, received 15 Feb 2010
- Expiration date of the lot/batch: 15 Jan 2011
- Storage condition of test material: room temperature in the dark over silica gel

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Laboratories, UK., Ltd, Oxon, UK
- Age at study initiation: nulliparous and non-pregnant
- Weight at study initiation: 15-23 g
- Fasting period before study:
- Housing: suspended solid floor polypropylene cages furnished with wood flakes
- Diet (e.g. ad libitum): ad libitum, 2014 Teklad Global Rodent diet supplied by Harlan Teklad, Blackthorn, Bicester, Oxon UK
- Water (e.g. ad libitum): ad libitum, free of contaminants as analyzed
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25 deg C
- Humidity (%): 30-70%
- Air changes (per hr): at least 15 changes per hour
- Photoperiod (hrs dark / hrs light): 12 h

Study design: in vivo (LLNA)

Vehicle:
propylene glycol
Concentration:
Range finding test: 25 uL of test material at 25% w/w in propylene glycol
Main test: 5, 10 and 25% w/w in propylene glycol
No. of animals per dose:
4 females per dose
Details on study design:
RANGE FINDING TESTS:
- Compound solubility: Compound was used as suspension in water
- Irritation: applied 3 consecutive days and observed up to day 6; any irritation was noted during this time
- Lymph node proliferation response: NDA

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA, 25%, 10% or 5% in propylene glycol applied on dorsal surface of ear 3 days in a row; [3H]-methyl thymidine was injected. All animals were observed daily, and weighed on day 1 and 6.
- Criteria used to consider a positive response: proliferation response was expressed as the number of radioactive disintegrations per mintue per lymph node and ratio of [3H]TdR incoproration relative to that recorded for control nodes was called the stimulation index. Material considered a sensitiser if ant least one cncentration resulted in a 3-fold greated incresase in radioactive incorporation compared tho the control values.

TREATMENT PREPARATION AND ADMINISTRATION: Test material was formulated withing 2 h of application; it was assumed that the formulation was stable; no analysis was conducted of compound, this is a deviation with regard to GLP.
Positive control substance(s):
other: phenylacetaldehyde (90%)

Results and discussion

Positive control results:
2.5% phenylacetaldehyde in propylene glycol resulted in a stimulation index of 4.2; it was considered to be a sensitiser

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: Vehicle - na 5% - 1.1 10% 0.88 25% - 0.93
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: Vehicle - 7529.69 dpm 5% - 8269.15 dpm 10% - 6613.97 dpm 25% 7025.55 dpm

Any other information on results incl. tables

No mortality or individual clinical observations

Concentration (% w/w) in
propylene glycol

Stimulation Index

Result

5

1.10

Negative

10

0.88

Negative

25

0.93

Negative

Table1            Clinical Observations, Bodyweight and Mortality Data – Preliminary Screening Test

Concentration (%w/w) in
propylene glycol

Animal Number

Bodyweight (g)

Day

1

2

3

4

5

6

Day 1

Day 6

Pre-Dose

Post Dose

Pre-Dose

Post Dose

Pre-Dose

Post Dose

25

S-1

20

18

0

0

0

0

0

0

0

0

0


0=      No signs of systemic toxicity

Table2            Disintegrations per Minute, Disintegrations per Minute/Node and Stimulation Index

Concentration
(%w/w) in
propylene glycol

dpm

dpm/Nodea

Stimulation Indexb

Result

Vehicle

7529.69

941.21

na

na

5

8269.15

1033.64

1.10

Negative

10

6613.97

826.75

0.88

Negative

25

7025.55

878.19

0.93

Negative

 


dpm=  Disintegrations per minute

a=      Disintegrations per minute/node obtained by dividing the disintegrations per minute value by 8 (total number of lymph nodes)

b=      Stimulation Index of 3.0 or greater indicates a positive result

na =   Not applicable

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
The test material was considered to be a non-sensitiser under the conditions of the test.
Executive summary:

A study was performed to assess the skin sensitisation potential of the test material in the CBA/Ca strain mouse following topical application to the dorsal surface of the ear. The method was designed to meet the requirements of the following: OECD Guideline for the Testing of Chemicals No. 429 "Skin Sensitisation: Local Lymph Node Assay" (adopted 24 April 2002) and Method B42 Skin Sensitisation (Local Lymph Node Assay) of Commission Regulation (EC) No. 440/2008

Following a preliminary screening test in which no clinical signs of toxicity were noted at a maximum attainable concentration of 25% w/w, this concentration was selected as the highest dose investigated in the main test of the Local Lymph Node Assay. Three groups, each of four animals, were treated with 50 µl (25 µl per ear) of the test material as a suspension in propylene glycol at concentrations of 25%,10% or 5% w/w. A further group of four animals was treated with propylene glycol alone.

The Stimulation Index expressed as the mean radioactive incorporation for each treatment group divided by the mean radioactive incorporation of the vehicle control group are as follows:

Concentration (%w/w) in
propylene glycol

Stimulation Index

Result

5

1.10

Negative

10

0.88

Negative

25

0.93

Negative

The test material was considered to be a non-sensitiser under the conditions of the test.