tert-pentyl hydroperoxide

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1994-1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

tert-pentyl hydroperoxide

EC Number:

222-321-7

EC Name:

tert-pentyl hydroperoxide

Cas Number:

3425-61-4

Molecular formula:

C5H12O2

IUPAC Name:

2-methylbutane-2-peroxol

Test material form:

other: liquid

Details on test material:

t-Amyl Hydroperoxide,
Lot 5867422102
Receipt Date: October 3, 1994
Physical Description : Clear colorless liqui
Storage Conditions: Room temperature
Expiration Date:February 9, 1995
Density: 0.91 g/ml
Purity 86.7 %

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Young adults rats were received at SLS from Charles River Laboratories, lnc., Portage, Michigan. 200 to 300 g prior to the study
Method of identification: Upon receipt, metal ear tags displaying unique identification numbers were used to individually identify the animais.
Housing: The animais were housed individually in suspended stainless steel cages.
Environment: The animal room temperature and relative humidity ranges were 65-70° F and 18-65%, respectively. Environmental control equipment was monitored and adjusted as necessary to minimize fluctuations in the animal room environment. Light timers were set to maintain a 12-hour light/12-hour dark cycle. There were ten to twelve air changes in the animal room per hour. The animal room temperature and relative humidity were recorded a minimum of once daily.
Food and water ad libitum
Quarantine: 5 days at minimum

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: dorsal trunk after the fur was removed (on day 1)
- % coverage: 10% of the animal's body surface are
- Type of wrap if used :porous gauze dressing, which was backed by plastic wrap (occlusive binding)

REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes, after removal of the dressing

TEST MATERIAL
- Amount(s) applied (volume or weight with unit):
- Concentration (if solution):
- Constant volume or concentration used: yes/no
- For solids, paste formed: yes/no

VEHICLE
- Amount(s) applied (volume or weight with unit):
- Concentration (if solution):
- Lot/batch no. (if required):
- Purity:

Duration of exposure:

24 hours

Doses:

0.27; 0.55; 0.82 ml/kg bw (equivalent to 250, 500 and 750 mg/kg bw based on a density of 0.91)

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations : LD50 study animals were observed for clinical abnormalities a minimum of two times on study day 0 (postdose) and daily thereafter (days 1-14). A mortality check was performed twice daily, in the morning and afternoon.
-Frequency of dermal observation: LD50 study animals were examined for erythema and edema following patch removal on study day 1 and daily thereafter (days 2-14) according to the Dermal Grading System
- lndividual body weights were obtained for the LD50 study animals prior to dosing on day 0 and for all surviving animais on days 7 and 14 and at the time of death for any animal dying on study.
- Necropsy of survivors performed: yes. All animals which died spontaneously during the study or were euthanized (carbon dioxide inhalation) at study termination (day 14) were necropsied. Body cavities (cranial, thoracic, abdominal and pelvic) were opened and examined. No tissues were retained.
- Other examinations performed: clinical signs, body weight,organ weights, histopathology.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

446 mg/kg bw

Based on:

test mat.

95% CL:

378 - 526

Mortality:

All mortality occured day 4

Clinical signs:

other: at 250 mg/k: dark material around the mouth and urine stain and were noted on study days 0-1 and 0-2, respectively For the surviving animals in the 500 and 750 mg/kg dose levels, clinical abnormalities included decreased activity, which was noted in two

Gross pathology:

For animals that died: discolored kidneys and/or spleen, reddened thymus, abnormal content in the small intestine, stomach, and urinary bladder, mottled lungs, congested meningeal vessels, reddened mucosa in the urinary bladder and reddened cervical lymph nades

Any other information on results incl. tables

Dose	Mortality in males	Mortality in females	Combined mortality
250	0/5	0/5	0/10
500	3/5	5/5	8/10
750	4/5	5/5	9/10

	LD50	95%Confidence Interval		95% Confidence Interval
Sex	(mg/kg)	(mg/kg)	Slope	Slope
Male	491.8	361.1 - 669.8	1.5	1.3-1.8
Female	353.6	294.0 - 425.2	1.2	1.2-1.3
Combined	446.3	378.5 - 526.3	1.4	1.3-1.5

Applicant's summary and conclusion

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

Under the conditions of this test, the acute dermal LD50 of t-Amyl Hydroperoxide in the male rat was determined to be 491.8 mg/kg. ln the female rat, the dermal LD50 was determined to be 353.6 mg/kg. ln the sexes combined, the acute dermal LD50 was determined to be 446.3 mg/kg

Executive summary:

An LD50 study was performed in which three groups of male and female rats received a single dermal administration of the test article at graded dosage levels. Following dosing, the LD50 study rats were observed daily and weighed weekly. A gross necropsy examination was performed on all LD50 study animals at the time of death or scheduled euthanasia (day 14).

All mortality occurred by study day 4.  The majority of clinical observations were observed in the 500 mg/kg and 750 mg/kg dose levels. In these group, for the surviving animals, clinical abnormalities included decreased activity, wobbly gait, transient incidences of rough haircoat, dark material around the facial area, reddish colored urine, decreased defecation, urine stain, eye(s) appeared dark and decreased food consumption.

For the animals that died during the study, notable clinical abnormalities included reddish colored urine, urine stain, dark material around the facial area, eye(s) appear dark, lacrimation, eyelids partially closed, decreased activity, prostration, and fasciculation. Dermal irritation was also noted at the site of test article application.

The most notable gross internal findings were observed in the animals that died and included discolored kidneys and/or spleen, reddened thymus, abnormal content in the small intestine, stomach, and urinary bladder, mottled lungs, congested meningeal vessels, reddened mucosa in the urinary bladder and reddened cervical lymph nodes.

Under the conditions of this test, the acute dermal LD50 of t-Amyl Hydroperoxide in the male rat was determined to be 491.8 mg/kg. ln the female rat, the dermal LD50 was determined to be 353.6 mg/kg. ln the sexes combined, the acute dermal LD50 was determined to be 446.3 mg/kg.