Tetraamminepalladium(2+) dichloride

Endpoint summary

Description of key information

In an in vivo guinea pig maximisation test (GPMT), conducted to GLP and according to OECD Test Guideline 406, tetraamminepalladium dichloride exhibited moderate skin sensitising potential (Allen, 2000).

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15-16 June 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD Guideline study, to GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Study conducted in 2000

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: David Hall Limited
Burton-on-Trent
Staffordshire
UK
- Age at study initiation:
- Weight at study initiation: 347-421 g
- Housing: solid-floor polypropylene cages; bedding - woodchips
- Diet (e.g. ad libitum): conventional; ad libitum
- Water (e.g. ad libitum): tap water; ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17-23
- Humidity (%): 30-70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Route:

intradermal and epicutaneous

Vehicle:

water

Concentration / amount:

0.01% in distilled water - injection
10% in distilled water - topical induction
1% and 2% in distilled water - topical challenge

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

0.01% in distilled water - injection
10% in distilled water - topical induction
1% and 2% in distilled water - topical challenge

No. of animals per dose:

10 (5 animals in control group)

Details on study design:

RANGE FINDING TESTS:
Intradermal induction: one animal each treated with 0.01, 0.05, 0.1, 0.5, 1.0 or 5% and examined for erythema at 24, 48 and 72 hr and at 7 days

Topical induction: Two guinea pigs (injected with Freund’s complete adjuvant 14 days earlier) each received applications of 5, 10, 25 and 50% of the test material under an occlusive dressing. Examined for erythema and odema at 1, 24 and 48 hr.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: One injection, followed 7 days later by topical application
- Exposure period: topical – 48 hr

- Test groups: Injection – three injections in shoulder region on each side of the mid-line as follows:
a) Freund's Complete Adjuvant plus distilled water in the ratio 1:1
b) 0.01% w/w formulation of the test material in distilled water
c) 0.01% w/w formulation of the test material in a 1:1 preparation of Freund's Complete Adjuvant plus distilled water.

- Control group: as above, but without the test material
- Site: shoulder region, on each side of the mid-line
- Frequency of applications: once
- Duration: topical – 48 hr
- Concentrations: 10%

B. CHALLENGE EXPOSURE
- No. of exposures: one
- Day(s) of challenge: 14 days after the topical induction
- Exposure period: 24 hr
- Test groups:
- Control group: treated with test substance as test group
- Site: flank
- Concentrations: 1% to left flank, 2% to right flank
- Evaluation (hr after challenge): 24 and 48 hr

Challenge controls:

Treated as for test group

Positive control substance(s):

no

Positive control results:

No positive controls included in this study. A table giving historical positive control data for 2-mercaptobenzothiazole is included in the study report, showing between a 70-100% incidence of sensitisation in groups of ten female guinea pigs.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

2%

No. with + reactions:

6

Total no. in group:

10

Clinical observations:

No evidence of adverse effects

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 2%. No with. + reactions: 6.0. Total no. in groups: 10.0. Clinical observations: No evidence of adverse effects.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

1%

No. with + reactions:

5

Total no. in group:

10

Clinical observations:

No evidence of adverse effects

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 1%. No with. + reactions: 5.0. Total no. in groups: 10.0. Clinical observations: No evidence of adverse effects.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

1 and 2%

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

One animal was found dead on day 14 from causes not related to the test material. No other clinical signs were evident.

Remarks on result:

other: see Remark

Remarks:

Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 1 and 2%. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: One animal was found dead on day 14 from causes not related to the test material. No other clinical signs were evident..

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

1 and 2%

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

One animal was found dead on day 14 from causes not related to the test material. No other clinical signs were evident.

Remarks on result:

other: see Remark

Remarks:

Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 1 and 2%. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: One animal was found dead on day 14 from causes not related to the test material. No other clinical signs were evident..

In test group with 2% challenge dose, at 48 hr 6 animals showed erythema (grades 1 and 2) and one animal had odema (at 24 hr the totals were 9 and 4, respectively for erythema and odema. Reactions that had disappeared by 48 hr were not attributed to sensitisation).

In test group with 1% challenge dose, at 48 hr 5 animals showed erythema (grade 1) and one animal had odema (at 24 hr the totals were 9 and 1, respectively for erythema and odema. Reactions that had disappeared by 48 hr were not attributed to sensitisation).

Interpretation of results:

Category 1A (indication of significant skin sensitising potential) based on GHS criteria

Conclusions:

In an in vivo guinea pig maximisation test (GPMT), conducted to GLP and according to OECD Test Guideline 406, tetraamminepalladium dichloride exhibited moderate skin sensitising potential

Executive summary:

Tetraammine palladium chloride was assessed for its contact sensitising potential in a guinea pig maximisation test (GPMT) conducted according to OECD Test Guideline 406, and to GLP.

A group of ten male animals were induced by intradermal injection of 0.1% of the test material (in distilled water), with and without Freund's Complete Adjuvant, followed 7 days later by topical exposure to 10% (in distilled water) under an occluded patch. Challenge doses of 1 and 2% (in distilled water) were applied to different sites 14 days later and the areas examined at 24 and 48 hr for erythema and oedema. A further group of five males were used as controls, receiving the same induction procedure but without the test substance, and challenged similarly to the treatment group.

Six of the ten treated animals showed evidence of sensitisation at 48 hr (erythema, grade 1 or 2); three further animals exhibited erythema at 24 hr but not at 48 hr and these reactions were therefore considered not to be due to sensitisation. Tetraamminepalladium chloride exhibited moderate skin sensitising potential in this study.

According to EU CLP criteria (EC 1272/2008), tetraamminepalladium chloride should be classifed as a skin sensitiser (category 1A).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

No relevant human sensitisation data were identified. No in vitro skin sensitisation studies were identified, or are required, as reliable in vivo studies are already available.

 

Tetraamminepalladium dichloride was assessed for its contact sensitising potential in a guinea pig maximisation test (GPMT) conducted according to OECD Test Guideline 406, and to GLP. A group of ten male animals were induced by intradermal injection of 0.1% of the test material (in distilled water), with and without Freund's Complete Adjuvant, followed 7 days later by topical exposure to 10% (in distilled water) under an occluded patch. Challenge doses of 1 and 2% (in distilled water) were applied to different sites 14 days later and the areas examined at 24 and 48 hr for erythema and oedema. A further group of five males were used as controls, receiving the same induction procedure but without the test substance, and challenged similarly to the treatment group. Six of the ten treated animals showed evidence of sensitisation at 48 hr (erythema, grade 1 or 2); three further animals exhibited erythema at 24 hr but not at 48 hr and these reactions were therefore considered not to be due to sensitisation. Tetraamminepalladium dichloride exhibited moderate skin sensitising potential in this study (Allen, 2000).

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 GPMT, tetraamminepalladium dichloride should be classified as a (strong) skin sensitiser (category 1A) according to EU CLP criteria (EC 1272/2008).