Diamminedichloropalladium

Endpoint summary

Description of key information

Diamminedichloropalladium gave no indication of skin sensitising potential at concentrations of up to 25% in a mouse local lymph node assay (LLNA), conducted according to OECD Test Guideline 429 study and to GLP (Pooles, 2012).

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

Study period:

03 April 2012 and 17 April 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD guideline study, to GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

No analysis was conducted to determine the homogeneity, concentration or stability of the test item formulation. This is an exception with regard to GLP and has been reflected in the GLP compliance statement.

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

other: CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories UK Ltd., Oxon, UK
- Age at study initiation: eight to twelve weeks
- Weight at study initiation: Range 15 to 23 g
- Housing: individually, in suspended solid floor polypropylene cages furnished with softwood woodflakes
- Diet (e.g. ad libitum): Free access to food (2014C Teklad Global Rodent diet supplied by Harlan Laboratories UK Ltd., Oxon, UK)
- Water (e.g. ad libitum): Free access to mains tap water
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25°C
- Humidity (%): 30 to 70%
- Air changes (per hr): approximately fifteen
- Photoperiod (hrs dark / hrs light): 12/12
- The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study

Vehicle:

other: ethanol/distilled water 7:3

Concentration:

25%, 10% or 5% w/w

No. of animals per dose:

5

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: The vehicle was chosen asa result of it producing the highest concentration that was suitable for dosing
- Irritation: One mouse was treated daily with 25 µl of 25% w/w of test substance in ethanol/distilled water (7:3) to the dorsal surface of each ear for three consecutive days (Days 1, 2, 3). Observation twice daily on Days 1, 2 and 3 and once daily on Days 4, 5 and 6. Local skin irritation was scored daily according to the scale for erythema [redness] - this can be seen in "Any other information on materials and methods ...", below. Any clinical signs of toxicity, if present, were also recorded. The bodyweight was recorded on Day 1 (prior to dosing) and on Day 6. The thickness of each ear was measured using an Oditest micrometer (Dyer, PA), pre dose on Day 1, post dose on Day 3 and on Day 6. Any changes in the ear thickness were noted. Mean ear thickness changes were calculated between Days 1 and 3 and between Days 1 and 6. A mean ear thickness increase of equal to or greater than 25% was considered to indicate excessive irritation and limited biological relevance to the endpoint of sensitisation. The preliminary screening test suggested that the test item would not produce systemic toxicity or excessive local irritation at the highest suitable concentration. Based on this information the dose levels selected for the main test were 25%, 10% and 5% w/w in ethanol/distilled water 7:3

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local lymph node assay
- Criteria used to consider a positive response: The proliferation response of lymph node cells was expressed as the number of radioactive disintegrations per minute per animal and as the ratio of 3HTdR incorporation into lymph node cells of test nodes relative to that recorded for the control nodes (Stimulation Index). The test item is regarded as a sensitiser if at least one concentration of the test item results in a threefold or greater increase in 3HTdR incorporation compared to control values. Any test item failing to produce a threefold or greater increase in 3HTdR incorporation is classified as a "non sensitiser".


TREATMENT PREPARATION AND ADMINISTRATION:
The mice were treated by daily application of 25 µl of the appropriate concentration of the test item to the dorsal surface of each ear for three consecutive days (Days 1, 2 and 3). The test item formulation was administered using an automatic micropipette and spread over the dorsal surface of the ear using the tip of the pipette.
The positive control animals were treated similarly to the test animals except that 25 µl of the positive control item, α-Hexylcinnamaldehyde, tech., 85%, at a concentration of 25% w/w in ethanol/distilled water 7:3 was applied to the dorsal surface of each ear.
Five days following the first topical application, mice were injected via the tail vein with 250 µl of phosphate buffered saline (PBS) containing 3H methyl thymidine (3HTdR:80µCi/ml, specific activity 2.0 Ci/mmol, ARC UK Ltd), giving a total of 20 µCi to each mouse. Five hours following the administration of 3HTdR all mice were killed and the draining auricular lymph nodes were excised and processed.
All animals were observed twice daily on Days 1, 2 and 3 and on a daily basis on Days 4, 5 and 6. Any signs of toxicity or signs of ill health during the test were recorded.
The bodyweight of each mouse was recorded on Day 1 (prior to dosing) and Day 6 (prior to termination).

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

Data was processed to give group mean values for disintegrations per minute and standard deviations where appropriate. Individual and group mean disintegrations per minute values were assessed for dose response relationships by analysis of homogeneity of variance followed by one way analysis of variance (ANOVA). In the event of a significant result from the ANOVA, pairwise comparisons were performed between control and treated groups. For homogenous datasets Dunnett’s Multiple Comparison test was used and for non homogenous datasets Dunnett’s T3 Multiple Comparison Method was used.
A probability value (p) of P>0.05 was considered to be not significant.

Positive control results:

Stimulation index: 15.75.

Parameter:

SI

Remarks on result:

other: Test item at 5%: 1.11 Test item at 10%: 0.80 Test item at 25%: 0.89

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

 

Bodyweight changes of the test animals between Day 1 and 6 were comparable to those observed in the corresponding control group animals over the same period.

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Diammine dichloropalladium gave no indication of skin sensitising potential at concentrations of up to 25% in a mouse local lymph node assay (LLNA), conducted according to OECD Test Guideline 429 study and to GLP.

Executive summary:

Diamminedichloropalladium was assessed for skin sensitisation potential in a mouse local lymph node assay (LLNA), carried out in accordance with OECD Test Guideline 429 and to GLP. Concentrations of 5, 10 and 25% in an ethanol/water vehicle were applied to the ears of groups of five mice for 3 consecutive days.

Diamminedichloropalladium produced proliferation indices in the range of 0.80 -1.11, indicating a lack of skin sensitisation potential. No adverse systemic effects were observed.

In conclusion, diamminedichloropalladium at concentrations of up to 25% gave no indication of skin sensitisation potential under the conditions of this LLNA assay. No classification for skin sensitisation is required, acording to EU CLP critiera.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

No relevant human sensitisation data were identified.

Diamminedichloropalladium was assessed for skin sensitisation potential in a mouse local lymph node assay (LLNA), carried out in accordance with OECD Test Guideline 429 and to GLP. Concentrations of 5, 10 and 25% in an ethanol/water vehicle were applied to the ears of groups of five mice for 3 consecutive days. Diamminedichloropalladium produced proliferation indices in the range of 0.80 -1.11, indicating a lack of skin sensitisation potential. No adverse systemic effects were observed. In conclusion, diamminedichloropalladium at concentrations of up to 25% gave no indication of skin sensitisation potential under the conditions of this LLNA assay (Pooles, 2012).

Justification for selection of skin sensitisation endpoint:
GLP study, conducted according to OECD guidelines, and the only skin sensitising study available.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

No respiratory tract sensitisation data are available. A new study was not conducted as no standard and validated test method is available and it is not a REACH Standard Information Requirement. 

Justification for classification or non-classification

Based on the results of the available and reliable mouse LLNA, diamminedichloropalladium does not require classification as a skin sensitiser according to EU CLP criteria (EC 1272/2008).