Disodium tetrachloropalladate

Sensitisation data (human)

Administrative data

Endpoint:

sensitisation data (humans)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Published paper, limited reporting. Data appear scientifically acceptable.

Data source

Reference

Reference Type:

publication

Title:

Sensitization to palladium in Europe

Author:

Muris J, Goossens A, Gonçalo M, Bircher AJ, Giménez-Arnau A, Foti C, Bruze M, Andersen KE, Rustemeyer T, Feilzer AJ and Kleverlaan CJ

Year:

2014

Bibliographic source:

Contact dermatitis 72, 11-19

Materials and methods

Type of sensitisation studied:

skin

Study type:

study with volunteers

Test guideline

Qualifier:

no guideline required

Principles of method if other than guideline:

To determine the prevalence of hypersensitivity (patch tests) to disodium tetrachloropalladate (and other platinum group elements) among 1651 patients attending various European dermatology clinics

Test material

Test material information

Constituent 1

Reference substance name:

Disodium tetrachloropalladate

EC Number:

237-502-6

EC Name:

Disodium tetrachloropalladate

Cas Number:

13820-53-6

Molecular formula:

Cl4Pd.2Na

IUPAC Name:

disodium tetrachloropalladate

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report): Sodium tetrachloropalladate (Na2PdCl4)
- Substance type: No data
- Physical state: No data
- Analytical purity: No data
- Impurities (identity and concentrations): No data
- Composition of test material, percentage of components: 2, 3 or 4% Na2PdCl4 in petrolatum
- Isomers composition: No data
- Purity test date: No data
- Lot/batch No.: No data
- Expiration date of the lot/batch: No data
- Stability under test conditions: No data
- Storage condition of test material: No data
- Other: Na2PdCl4 was ground with a porcelainmortar and pestle. Then 2, 3 and 4 g were added to 98, 97 and 96 g of pet., respectively. Na2PdCl4 with the pet. was then suspended in a glass laboratory bottle by heating (55 deg C) in a ultrasonic cleaning unit with intermittent stirring for 4 hr until a homogeneous suspension was obtained. Sterile syringes were then filled with 2%, 3% and 4% Na2PdCl4 pet. and labelled. One batch for each test concentration was used to prepare the syringes for all test centres.

Method

Type of population:

general

Ethical approval:

other: Not required

Subjects:

- Number of subjects exposed: 1651 (for 3% Na2PdCl4); 1634 (for 2 and 4% Na2PdCl4)
- Sex: Male and female (exact numbers not specified for the entire set of subjects; for the subset of 906 patients, 269 were male and 637 were female)
- Age: For the subset of 906 patients, the mean age was 48.3 years
- Race: No data
- Demographic information: Patients were tested in eight European clinics: Amsterdam (n=66), Barcelona (n=118), Bari (n=90), Basle (n=175), Coimbra (n=190), Leuven (n=267), Malmo (n=353) and Odense (n=392)
- Other: The subset of 906 patients from Amsterdam, Barcelona, Bari, Basle, Coimbra and Leuven had additional information on age and sex. Seventeen patients were not tested with 2% and 4% Na2PdCl4, leaving 1634 patients who were tested with these concentrations.

Clinical history:

- History of allergy or casuistics for study subject or populations: Patients with or without active eczema
- Symptoms, onset and progress of the disease: No data
- Exposure history: No data
- Aggravating factors both in home and workplace: No data
- Family history: No data
- Medical history (for respiratory hypersensitivity): No data
- Any other allergic or airway disorders: No data
- Smoking history: No data

Controls:

No data

Route of administration:

dermal

Details on study design:

Patch tests were conducted with 2, 3 and 4% disodium tetrachloropalladate in petrolatum. Patch testing was performed according to the recommendations of the ICDRG. Some test centres preferred to perform readings on D4 instead of D3, which was accepted for the purpose of this study. Except for Basel, Coimbra, and Leuven, all centres performed standard additional readings after 1 week (D7).

Patch tests were regarded as positive if a positive reaction (+, ++, or +++) to the metal salts was observed in at least one reading. If a positive reaction was observed at more than one reading, the strongest reaction defined the actual test result. For statistical analyses, all positive reactions (+, ++, or +++) were clustered as positive. Doubtful reactions (±) and irritant reactions (IRs) were also recorded, but regarded as negative test results.

General exclusion criteria were age under 18 years, pregnancy, systemic corticosteroid or immunosuppressive treatment during the previous 30 days, and topical treatment with corticosteroids or exposure to ultraviolet radiation during the previous 15 days on or around the patch test area.

Results and discussion

Results of examinations:

NO. OF PERSONS WITH/OUT REACTIONS COMPARED TO STUDY POPULATION
2% Disodium tetrachloropalladate
- Number of subjects with positive reactions: approx. 15%
- Number of subjects with negative reactions: approx. 85% (equivocal and irritant reactions were regarded as negative results)
- Number of subjects with equivocal reactions: 72/1634 (4.4%)
- Number of subjects with irritating reactions: 1/1634 (0.1%)

3% Disodium tetrachloropalladate
- Number of subjects with positive reactions: 300/1651 (18.2%)
- Number of subjects with negative reactions: 1351/1651 (81.8%) (equivocal and irritant reactions were regarded as negative results)
- Number of subjects with equivocal reactions: 68/1651 (4.1%)
- Number of subjects with irritating reactions: 1/1651 (0.1%)

4% Disodium tetrachloropalladate
- Number of subjects with positive reactions: 306/1634 (18.7%)
- Number of subjects with negative reactions: 1328/1634 (81.3%) (equivocal and irritant reactions were regarded as negative results)
- Number of subjects with equivocal reactions: 56/1634 (3.4%)
- Number of subjects with irritating reactions: 3/1634 (0.2%)

Applicant's summary and conclusion

Conclusions:

Skin patch tests with disodium tetrachloropalladate (3% in petrolatum) produced a positive reaction in 300 of 1651 (18.2%) patients attending various European dermatology clinics. Analogous tests with 2 and 4% concentrations produced a positive reaction in approximately 15 and 18.7% of the subset of 1634 patients, respectively.

Executive summary:

In an attempt to determine the prevalence of hypersensitivity to various platinum group elements (PGEs), 1651 patients (with and without active eczema) attending eight European dermatology clinics were patch tested with disodium tetrachloropalladate (3% in petrolatum). Patch test readings were scored according to international guidelines on days 3 or 4 and on day 7 after skin testing in the majority of clinics. Positive reactions to disodium tetrachloropalladate were observed in 300 (18.2%) of the 1651 patients. Analogous tests with 2 and 4% concentrations produced a positive reaction in approximately 15 and 18.7% of the subset of 1634 patients, respectively.