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Acute Toxicity: dermal

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acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
supporting study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference Type:
study report
Report Date:

Materials and methods

Test guideline
equivalent or similar to
OECD Guideline 402 (Acute Dermal Toxicity)
only 1 animal per dose level, only one sex tested, necropsy on only 7 of the 9 animals conducted
GLP compliance:
not specified

Test material

Details on test material:
- Name of test material (as cited in study report): ortho-Phenylenediamine (OPD).
- Samples were obtained by chipping pieces (mainly orange-brown) from the top layers of a solidified mass of orange-brown, yellow brown, and black layers, and grinding them into a uniform mixture. When the material was dispersed into a hydrophilic ointment USP, an orange paste usually formed. On one occasion, a yellow-brownish paste formed.

Test animals

other: albino
Details on test animals and environmental conditions:
- Age at study initiation: Not reported
- Weight at study initiation: 2.5-3.0 g
- Fasting period before study: None
- Housing: Not reported
- Diet (e.g. ad libitum): Not reported
- Water (e.g. ad libitum): Not reported
- Acclimation period: Not reported

- Temperature (°C): Not reported
- Humidity (%): Not reported
- Air changes (per hr): Not reported
- Photoperiod (hrs dark / hrs light): Not reported

Administration / exposure

Type of coverage:
other: hydrophilic ointment or polypropylene glycol
Details on dermal exposure:
TEST SITE: Rabbits were clipped at the trunk and fitted with collars.

- Washing (if done): After 24 hours contact, wrappings were removed and the treated areas were washed with water and dried.

- For solids, paste formed: Yes; material suspended in polypropylene glycol and applied through a single layer of gauze wrapped around the clipped trunk. For higher doses, a 50% paste of the material in hydrophilic ointment, U.S.P., was applied directly to the clipped skin without gauze. After application, all rabbits were then wrapped with impervious film, gauze, and elastic bandage.
Duration of exposure:
24 hours
450, 670, 1000, 1500 (in polypropylene glycol), 1500, 2250 (yellow brown paste), 2250 (orange paste), 7500 and 11000 mg/kg
No. of animals per sex per dose:
Control animals:
Details on study design:
Animals were observed for 14 days before sacrifice. Necropsies were done on 7 of the 9 animals treated, and major tissues of 6 rabbits were saved for histopathological examination. No-necropsy rabbits: dosed at 11000 mg/kg and at 1500 mg/kg of the test substance in hydrophilic ointment; necropsy only - rabbit dosed at 1500 mg/kg of the test substance in polypropylene glycol.

Tissues examined included kidney, liver, trachea, lung, brain, testes, bone marrow, spleen, thymus, gastrointestinal tract and skin.

Results and discussion

Effect levels
Dose descriptor:
other: Approximate Lethal Dose (ALD)
Effect level:
1 500 mg/kg bw
Dose Level Mortality Ratio

450 (in 50% H.O.): 0/1
670 (in 50% H.O.): 0/1
1000 (in 50% H.O.): 0/1
1500 (in 15% DMP): 0/1
1500 (in 50% H.O.): 1/1
2250 (in 50% H.O.)
yellow brown paste: 0/1
2250 (in 50% H.O.)
orange paste: 1/1
7500 (in 50% H.O.): 1/1
11,000 (in 50% H.O.): 1/1
Clinical signs:
Clinical signs of toxicity observed included haematuria and abnormally dark urine, hyperemic eyelids, salivation, and debility.

Local signs: Irritation in most cases was at least partially obscured by residual dye. However, the rabbit dosed at 1000 mg/kg showed initial erythema and edema followed by desquamation. Initial erythema was noted at dose levels above 450 mg/kg.
Body weight:
2250 mg/kg (yellow brown paste): significant weight loss through 14 days
2250 mg/kg (orange paste): weight loss slight at 1 day, severe at 2 days
Gross pathology:
The following pathologic changes were observed at lethal doses:
Bladder - distended with red-tinged urine (gross exam)
Kidney - congestion (gross exam), inflammation and papillary necrosis (7500 mg/kg)
Liver - necrosis (2250 mg/kg)
Spleen - atrophy of lymphoid elements
Skin - necrosis of epithelium of deeper portions of hair follicles
Bone marrow - generalized necrosis
Thymus - lymphocytolysis
Small intestine - degeneration

The following pathologic changes were observed at non-lethal doses:
Kidney - papillary necrosis (2250 mg/kg)
Thymus - lymphoid atrophy at doses above 450 mg/kg
Bone marrow - generalized necrosis (2250 and 1000 mg/kg with regenerative response at 1000 mg/kg)
Other findings:
In general, the orange-brown fraction appeared to be more toxic than the yellow-brown fraction in the skin absorption test.

Applicant's summary and conclusion

Interpretation of results:
Category 4 based on GHS criteria
Dermal ALD = 1500 mg/kg
Executive summary:

The Approximate Lethal Dose (ALD) was 1500 mg/kg for rabbits when the test material was administered as 50% paste in hydrophilic ointment, U.S.P. Clinical signs of toxicity included haematuria and abnormally dark urine, hyperemic eyelids, salivation, and debility. Pathologic examination was done in most cases and showed frequent tissue changes in kidney, liver, bone marrow, lymphoid tissue, small intestine and skin. Local reaction was frequently obscured by the colour of the test material; however, temporary moderate to mild irritation from occluded 24 hour contact was sometimes noted. In general, the orange-brown fraction appeared to be more toxic than the yellow-brown fraction in the skin absorption test.