Dicarbonyl(pentane-2,4-dionato-O,O')rhodium

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study apparently performed according to the method described in Federal Register 1973, Vol. 38, No. 187, Section 1500:41, which has some significant deviations from current OECD guidelines. Limited reporting, notably of test material (e.g. purity).

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1977

Report date:

1977

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Skin irritation patch test, as described in Federal Register 1973, Vol. 38, No. 187, Section 1500:41.

Deviations:

not specified

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Dicarbonyl(pentane-2,4-dionato-O,O')rhodium

EC Number:

238-947-9

EC Name:

Dicarbonyl(pentane-2,4-dionato-O,O')rhodium

Cas Number:

14874-82-9

Molecular formula:

C7H7O4Rh

IUPAC Name:

Dicarbonyl(pentane-2,4-dionato-O,O')rhodium

Details on test material:

- Name of test material (as cited in study report): rhodium dicarbonyl acetylacetonate
- Lot/batch No.: Sample CB.23

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: “recognised breeders”
- Age at study initiation: 16-18 weeks
- Weight at study initiation: 2.2-2.4 kg
- Housing: unspecified numbers per cage
- Diet: ad libitum commercial rabbit diet supplied by Rank Hovis MacDougal
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Photoperiod (hrs dark / hrs light): “natural lighting conditions”

Test system

Type of coverage:

occlusive

Preparation of test site:

other: Backs of the rabbits were shaved (not “closely clipped” as recommended by the OECD guidelines). One site of each rabbit was abraded immediately before application of the test material, the other site remained intact.

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 ml

Duration of treatment / exposure:

24 hrs

Observation period:

48 hrs after removal of the patch

Number of animals:

six

Details on study design:

TEST SITE
- Area of exposure: Each site 2.5 cm2 (one intact, one abraded)
- % coverage: at least 10%
- Type of wrap if used: Gauze pad was secured by “Sleek” adhesive tape

REMOVAL OF TEST SUBSTANCE
- Washing (if done): None

SCORING SYSTEM: Erythema (and eschar) formation and oedema formation were assessed on the intact and abraded skin of six rabbits at 24 and 72 hr after initial application of the test compound (i.e. as soon as the dressing was removed and again 48 hrs later). The primary irritation index was calculated by adding the four values for erythema (and eschar) formation to the four for oedema formation, and dividing the total by four. According to the study report, Draize (1959) considers that “compounds producing combined averages (primary irritation indices) of 2 or less are only mildly irritating; whereas those with indices of 2 to 5 are moderate irritants, and those with scores above 6 are considered severe irritants”.

Results and discussion

In vivo

Results

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 24 and 72 hrs after initial application

Score:

0.7

Max. score:

8

Reversibility:

other: Reversibility not assessed, as observation period only 48 hrs (not up to 14 days as recommended in the OECD guidelines). However, on the majority of occasions where irritation (score of 1 or 2) was noted after dressing removal, the severity of the irritat

Remarks on result:

other: Average score for abraded and intact skin

Irritant / corrosive response data:

On the intact skin, slight erythema was seen in two (out of 6) rabbits assessed after dressing removal, which was still observed on one of these animals assessed 48 hours later. No oedema was reported on the intact skin of any treated animals assessed at either time point (0 or 48 hours after dressing removal).

Other effects:

No further effects were reported.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In an in vivo skin irritation study, rhodium dicarbonyl acetylacetonate (0.5 mL) produced a primary irritation index of 0.7 following 24-hr occlusive application to the shaved abraded and intact skin of six rabbits. This study was not performed to current OECD guidelines.

Executive summary:

Rhodium dicarbonyl acetylacetonate (0.5 ml) was applied (occluded) to the shaved abraded and intact skin of six albino rabbits. After 24 hrs, the dressings were removed and the sites were quantitatively assessed for erythema (and eschar) formation and oedema formation. Similar assessments were made 48 hrs later. The sum of these values was combined and divided by four to give a primary irritation score of 0.7 (out of a possible 8).On the intact skin, slight erythema (but no oedema) was seen in two rabbits assessed after dressing removal, which was still observed on one of these animals assessed 48 hours later. Overall, rhodium dicarbonyl acetylacetonate was mildly irritating in this test system as there was a tendency for reversibility of effects over time.

 

This study suffered from a number of significant deviations from the recommendations given in the current OECD guidelines. These included use of abraded skin, a longer exposure period, failure to wash off any residual test material after removal of the dressing, an insufficient observation period to assess reversibility of effects, and the skin was only examined on two occasions (at 0 and 48 hrs), rather than at 1, 24, 48 and 72 hrs after patch removal. However, certain of these deviations would have likely increased the possibility of an irritant reaction .

 

Mean erythema and oedema scores were below 2.3 for all six animals. Accordingly, rhodium dicarbonyl acetylacetonate does not require classification for skin irritation according to EU CLP criteria (EC 1272/2008).