Solvent naphtha (petroleum), heavy arom.

Repeated dose toxicity: dermal

Administrative data

Endpoint:

sub-chronic toxicity: dermal

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP compliant, near guideline study, available as unpublished report, minor restrictions in design and/or reporting but otherwise adequate for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1985

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)

Deviations:

yes

Remarks:

dosing 3 times per week

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Naphtha (petroleum), heavy catalytic reformed

EC Number:

265-070-9

EC Name:

Naphtha (petroleum), heavy catalytic reformed

Cas Number:

64741-68-0

IUPAC Name:

64741-68-0

Constituent 2

Reference substance name:

Heavy catalytic reformed naphtha (petroleum)

IUPAC Name:

Heavy catalytic reformed naphtha (petroleum)

Details on test material:

- Name of test material (as cited in study report): API 83-06 Heavy catalytic reformed naphtha.
- Description: A complex combination of hydrocarbons produced from the distillation of products from a catalytic reforming process. It consists of predominantly aromatic hydrocarbons having carbon numbers predominantly in the range of C7 through C12 (approx. 91% aromatics, 9% paraffins: no benzene reported present). It has a boiling range of approximately 90°C to 230°C (194-446°F).
- Physical state: clear liquid.

Test animals

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hazleton Dutchland Inc., Denver, Pennsylvania, USA
- Age at study initiation: Young adult
- Weight at study initiation: mean weights per group 2.6-3.6 kg (males), 2.4-3.4 kg (females)
- Housing: Individually in stainless steel cages with grid bottoms
- Diet: Purina Laboratory Rabbit Chow #5321 ad libitum
- Water: ad libitum
- Acclimation period: 20-24 days

ENVIRONMENTAL CONDITIONS
- Temperature: 22±3°C
- Humidity: 63-83%:
- Air changes: 10-15 per hr
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: From: 23 July 1984 To: 24 August 1984

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on exposure:

TEST SITE
- Area of exposure: trunk (approximately 15 cm x 20 cm)
- % coverage: approximately 10% of total body surface
- Type of wrap if used: surgical gauze pad, wrapped with a sheet of polythene and secured with hypoallergenic tape.
- Time intervals for shavings or clippings: approximately 24 hours prior to each application

REMOVAL OF TEST SUBSTANCE
- Washing (if done): wiped with a clean dry absorbent gauze pad (not washed).
- Time after start of exposure: 6 hours

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): Based on the weekly bodyweight of each animal and the specific gravity (0.7480 g/mL) of API 83-06.

USE OF RESTRAINERS FOR PREVENTING INGESTION: no

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

28 days

Frequency of treatment:

three times per week (total of 12 applications)

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 200, 1000, 2000 mg/kg/day
Basis:
nominal per unit body weight

No. of animals per sex per dose:

5

Control animals:

yes, sham-exposed

Details on study design:

- Dose selection rationale: Doses determined in a pilot 5 day dermal study in which moderate dermal irritation was the only treatment-related finding. No justification is provided for the frequency of dosing in the main study.

Examinations

Observations and examinations performed and frequency:

MORTALITY AND CLINICAL OBSERVATIONS: Yes
- Time schedule: twice daily.

DERMAL IRRITATION (if dermal study): Yes
- Time schedule for examinations: twice daily (Draize scoring system used).

BODY WEIGHT: Yes.
- Time schedule for examinations: At start, weekly thereafter and at termination.

FOOD CONSUMPTION: No

WATER CONSUMPTION: No

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at termination
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: all
- Parameters examined: erythrocyte count, total leukocyte count, differential leukocyte count, haemoglobin, haematocrit

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at termination
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: all
- Parameters examined: glucose, blood urea nitrogen, alkaline phosphatase, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, total protein

URINALYSIS: No (urine collected from all control and high dose animals prior to initiation of dosing and at termination. Frozen and stored for possible future evaluation).

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
ORGAN WEIGHTS: heart, liver, spleen, kidneys, adrenals, thyroids (with parathyroids), pituitary, testes, ovaries, brain
HISTOPATHOLOGY: Yes. The following tissues from all control and high dose animals were examined: heart, lungs, bronchi, trachea, thyroids, parathyroids, cervical lymph nodes, salivary gland, tongue, oesophagus, stomach, duodenum, jejunum, ileum, sacculus rotundus, colon, thymus, spleen, liver, pancreas, kidneys, adrenals, vagina, seminal vesicles, testes/ovaries, epididymes, prostate, uterus, mesenteric lymph nodes, urinary bladder, mammary gland, brain (cerebellum, cerebrum, pons), pituitary, spinal cord (2 sections), skeletal muscle, sciatic nerve, skin (treated and untreated), bone, bone marrow (smear), eyes, gross lesions

Statistics:

2-tailed Student's t-test at the 5% probability level.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Dermal irritation:

effects observed, treatment-related

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Details on results:

CLINICAL SIGNS AND MORTALITY: No mortalities and no clinical signs of systemic toxicity.

DERMAL IRRITATION: Erythema and oedema, cracked, flaky and/or leathery skin at or around application site in all rabbits. 2000 and 1000 mg/kg - severe irritant, 200 mg/kg moderate irritant (males), slight/moderate irritant (females). Erythema (scores of 1-4 in males; 1-3 in females) were seen in all animals from about day 5 and persisted until the end of the study. Oedema was also seen in males.

BODY WEIGHT AND WEIGHT GAIN: Slight statistically significant reduction in overall bodyweight gain for males at 2000 mg/kg/day. Statistically significantly lower bodyweights for females at 1000 mg/kg/day (days 8 and 29) and at 2000 mg/kg/day (days 8, 15 and 29) and statistically significantly reduced overall bodyweight gain at 2000 mg/kg/day. However, since weight loss/gain of 0.1 or 0.2 kg is frequently observed in rabbits of this strain, no definite conclusions can be drawn from this data.

HAEMATOLOGY: No treatment-related effects.

CLINICAL CHEMISTRY: No treatment-related effects.

ORGAN WEIGHTS: No treatment-related effects.

GROSS PATHOLOGY: Effects confined to treated skin and consisted of reddened, dry, flaky, cracked, leathery and/or thickened skin

HISTOPATHOLOGY: In the high dose group: moderate to moderately severe proliferative and moderate to severe inflammatory changes of the treated skin. Concurrent with these changes there was increased granulopoiesis of the bone marrow, which may be related to the stress or other factors associated with the severe skin irritation. Low and intermediate dose groups were not examined histopathologically.

Effect levels

1

Dose descriptor:

NOAEL

Remarks:

systemic toxicity

Effect level:

2 000 mg/kg bw/day (nominal)

Sex:

male

Basis for effect level:

other: no treatment-related effects at highest dose tested (2000 mg/kg/day)

2

Dose descriptor:

LOAEL

Remarks:

dermal irritation

Effect level:

200 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: slight to moderate irritation at lowest dose tested

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Following repeated 6-hour dermal applications of Heavy catalytic reformed naphtha (API 83-06) to the rabbit skin over a period of 28 days (3 times/week, total of 12 applications), the NOAEL was 2000 mg/kg/day for males and females. Signs of severe skin irritation were seen.

Executive summary:

Repeated dose (6-hour dermal applications) toxicity of heavy catalytic reformed naphtha (API 83-06) was investigated in groups of 5 male and 5 female rabbits. The neat test substance was applied to skin over a period of 28 days (3 times/week, total of 12 applications) at doses of 0, 200, 1000 or 2000 mg/kg/day. Animals were observed daily for clinical signs of toxicity and skin irritation, bodyweight was measured at intervals and at the end of the study blood samples were analysed for changes in haematology and clinical chemistry, a selection of organs were weighed and a full range of tissues examined histopathologically.

The NOAEL for heavy catalytic reformed naphtha (API 83-06) (CAS 64741-68-0) for systemic toxicity was 2000 mg/kg/day. A NOAEL was not established for local irritant effects - 200 mg/kg was a LOAEL based on slight to moderate irritation based on Draize scores.