Distillates (petroleum), light distillate hydrotreating process, low-boiling

Repeated dose toxicity: dermal

Administrative data

Endpoint:

short-term repeated dose toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1985/11/04 - 1985/12/10

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well-documented study report in general agreement with OECD guideline 410. The treated site used an occlusive wrapping that alters the interpretation of the results. - GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1985

Report date:

1986

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:

the treated site used an occlusive wrapping.

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Gasoline

EC Number:

289-220-8

EC Name:

Gasoline

Cas Number:

86290-81-5

IUPAC Name:

Gasoline

Constituent 2

Reference substance name:

Premium unleaded gasoline

IUPAC Name:

Premium unleaded gasoline

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Simonsen laboratories
- Age at study initiation: approximately 8 weeks at receipt
- Weight at study initiation: Males: 200-300 g; Females: 125-200 g
- Housing: individually
- Diet (e.g. ad libitum): fresh purina certified rodent chow (#5002), ad libitum
- Water (e.g. ad libitum): of potable quality, analyzed periodically for impurities, ad libitum
- Acclimation period: phase I: at least one week (minimum); Phase II: at least 7 days (minimum)

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 68-76
- Humidity (%): 40-60%
- Photoperiod (hrs dark / hrs light): 12hrs dark /12 hrs light cycle

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on exposure:

TEST SITE
- Area of exposure: backs of the animals
- % coverage: approximately 10% of the total body surface area
- Type of wrap if used: skin at site of application will be covered with gauze patches secured in place with surgical hypoallergenic adhesive tape. The trunk of the animal is wrapped with an impervious material (i.e., plastic wrap).
- Time intervals for shavings or clipplings: approximately 24 hours prior to the first application of the test article, the backs of all animals will be closely clipped of hair (may be repeated as needed in the study)

REMOVAL OF TEST SUBSTANCE
- Washing (if done): after removal of the wrap and patch, any residual test article or control article will be wiped from the application site if possible
- Time after start of exposure: at the end of the occlusion period


TEST MATERIAL
The actual quantities applied will be documented for each animal at each application

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

Phase I: five consecutive days
Phase II: five consecutive days per week for four (4) weeks

Frequency of treatment:

once per day

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
Phase I: 375, 750, 1875, 3750, 7500 mg/kg
Basis:
nominal per unit body weight

Doses / concentrations 2

Remarks:

Doses / Concentrations:
Phase II: 375, 1500, 3750 mg/kg
Basis:
nominal per unit body weight

No. of animals per sex per dose:

Phase I: 2 per sex per dose.
Phase II: 10 per sex per dose.

Control animals:

yes, sham-exposed

Details on study design:

The test article was evenly applied to clipped, intact skin sites (~10% total body surface), once per day for five consecutive days. The area of application was approximately ten percent of the total body surface area. The actual quantities applied were documented for each rat at each application interval. Following each application of the test article during all study phases, the treated skin was covered with a gauze patch secured in place with surgical hypoallergenic adhesive tape. The trunk of the animal was then wrapped with an impervious material (wrap). Occlusion lasted for 6 hours after each application. At the end of the occlusion period, the wraps and patches were removed, and any residual test article wiped from the application sites if possible.

Positive control:

None

Examinations

Observations and examinations performed and frequency:

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: twice daily, at least six hours apart

DERMAL IRRITATION (if dermal study): Yes
- Time schedule for examinations: evaluated and recorded daily on each of the five days just prior to test article application, approximately 24hours after the fifth application and just prior to necropsy for erythema, edema, eschar, excessive irritation, fissuring and/or necrosis of the skin according to a modified method of the Draize scoring system

BODY WEIGHT: Yes
- Time schedule for examinations: measured and recorded for each rat near the end of the quarantine period, then on each of the five dosing days of Phase I, three days per week during Phase II and at necropsy

HAEMATOLOGY: Yes
- Time schedule for collection of blood: only at the termination Phase II of the study, on all surviving animals.
- How many animals: all surviving animals
- Parameters examined: erythrocyte count, total leukocyte count, differential leukocyte count, hemoglobin, hematocrit

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: only at the termination Phase II of the study, on all surviving animals.
- How many animals: all surviving animals
- Parameters examined: blood urea nitrogen, glucose, creatinine, cholesterol, triglyceride, total protein, alkaline phosphatase, aspartate aminotransferase (SGOT/AST), alanine aminotransferase (SGPT/ALT)

Sacrifice and pathology:

Phase III (no tissues will be saved in Phase I and II): Necropsy - included the gross examination of the external body surfaces, all orifices, cranial cavity, external and cut surfaces of brain, spinal cord, cervical, thoracic, and abdominal viscera, carcass.

Statistics:

Phase II - body weights, clinical pathology, terminal body weights, and absolute and relative organ body weight data of the control groups were statistically compared to the treated group data of the same sex, using a two-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:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY: The irritation in the low dose group (375 mg/kg) was moderate to severe erythema with little edema. The females exhibited a slightly higher irritation than the males. Irritation in the mid dose group (1500 mg/kg) was severe. Eschar formation was common to all animals in the group by Day 8. Dried skin and fissuring were also common lesions. The high dose group (3750 mg/kg) was similar to the mid-dose group except that eschar appeared in all animals at Day 5 and edema was more evident in the first week of dosing in the high dose group. One male in the control group died, which is believed to be due to the massive malocclusion which prevented the animal from eating and drinking properly.


BODY WEIGHT AND WEIGHT GAIN: There were no statisticaly significant differences in body weights between the controls and tests group during this study. However, there was a decrease in the weight gain in the male rats and was greatest in the high dose group.


HAEMATOLOGY: The red blood cells count for the high dose (3750 mg/kg) females was significantly lower compared to controls. Neutrophil counts were significantly higher in the high dose (3750 mg/kg) males, eosinophil counts were significantly higher in the mid-dose (1500 mg/kg) females, and lymphocyte counts were significantly lower in the high dose (3750 mg/kg) males as compared to controls. Hematrocrit percentage was significantly higher for the low dose and mid-dose males as compared to controls.

CLINICAL CHEMISTRY: SGPT levels were significantly lower in the mid-dose and high dose males as compared to controls. Glucose levls were significantly higher for the female mid and high dose groups.


ORGAN WEIGHTS: Male liver weights were significantly lower in the low dose (375 mg/kg) and high dose (3750 mg/kg) groups. The male liver/body weights ratio was significantly lower in the low dose group. The female liver/body weights ratio was significantly higher in the high dose group (3750 mg/kg). The male liver/brain weights ratio was significantly lower in the low dose (375 mg/kg) and high dose (3750 mg/kg) groups. The female kidney/brain weights ratio was significantly higher in mid-dose (1500 mg/kg) group.


GROSS PATHOLOGY: Most lesions observed were related to dermal irritation such as dried skin and eschar formation at the exposure site.


HISTOPATHOLOGY: NON-NEOPLASTIC: The only histopathologic finding observed in the non-dermal tissues was eosinophilic casts in the kidneys of control and high dose rats considered to be a spontaneous or naturally occurring lesion expected in Sprague Dawley rats. Dermal findings at the treated skin application site of high dose rats were acanthosis, dermal fibrosis, hyperkeratosis, epidermal crusting, dermal inflammation, and ulceration. All lesions ranged from minimal to mild in severity except for epidermal crusting and ulceration in animal 823322 which were both graded moderate in severity. These dermal lesions were multifocal in distribution pattern.

Effect levels

1

Dose descriptor:

NOAEL

Remarks:

Systemic

Effect level:

3 750 mg/kg bw/day

Sex:

male/female

2

Dose descriptor:

NOAEL

Remarks:

Dermal Irritation NOAEL - Occlusive Dressing

Effect level:

< 375 mg/kg bw/day

Sex:

male/female

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

The results of this study should be interpreted with care. The experimental paradigm utilized an occlusive dressing to retain the test material. Due to the test material’s volatilization properties, the occlusive dressing prevents the material from evaporating off the skin. This results in changes to the permeability of the dermis that artificially increases the irritation score and increases absorption of the test material. The results from this study could be interpreted as a worst case scenario because of the increased absorption. Under the conditions of this study, F-64-01 produced reversible dermal irritation with eschar formation at the lower dose levels (375 mg/kg and 1500 mg/kg) and possible irreversible dermal irritation at 3750 mg/kg when exposed to rats under the test system described. No statistically significant toxicological or pharmacological signs were observed at any dose level other than the dermal irritation. The dermal irritation NOAEL was <375 mg/kg. The systemic NOAEL was 3750 mg/kg.

Executive summary:

F-64 -01 was applied to clipped, intact skin sites, once per day, five times per week, for the duration of the study (4 weeks) at doses of 0, 375, 1500 and 3750 mg/kg. Following each application of the test article during the study phases, the treated skin was covered with an occlusive dressing for 6 hours.  At the end of the occlusion period, the residual test article was wiped from the application sites.  Dermal irritation was scored using the Draize methodology.  In addition to dermal irritation, hematological, clinical chemistry and histopathology were examined.

The results of this study should be interpreted with care.  The experimental paradigm utilized an occlusive dressing to retain the test material.  Due to the test material’s volatilization properties, the occlusive dressing prevents the material from evaporating off the skin.  This results in changes to the permeability of the dermis that artificially increases the irritation score and increases absorption of the test material.  The results from this study could be interpreted as a worst case scenario because of the increased absorption.  Under the conditions of this study, F-64-01 produced reversible dermal irritation with eschar formation at the lower dose levels (375 mg/kg and 1500 mg/kg) and possible irreversible dermal irritation at 3750 mg/kg when exposed to rats under the test system described. No statistically significant toxicological or pharmacological signs were observed at any dose level other than the dermal irritation.  The dermal irritation NOAEL was <375 mg/kg.  The systemic NOAEL was 3750 mg/kg.