N-(2-ethylhexyl)-8,9,10-trinorborn-5-ene-2,3-dicarboximide

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17 November 2004 to 26 April 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Version / remarks:

December 2002

Deviations:

not specified

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 425 (Acute Oral Toxicity: Up-and-Down Procedure)

Version / remarks:

December 17,2001

Deviations:

not specified

GLP compliance:

yes

Test type:

up-and-down procedure

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

N-(2-ethylhexyl)-8,9,10-trinorborn-5-ene-2,3-dicarboximide

EC Number:

204-029-1

EC Name:

N-(2-ethylhexyl)-8,9,10-trinorborn-5-ene-2,3-dicarboximide

Cas Number:

113-48-4

Molecular formula:

C17H25NO2

IUPAC Name:

N-(2-ethylhexyl)-8,9,10-trinorborn-5-ene-2,3-dicarboximide

impurity 1

Reference substance name:

(E)-1,4-Bis(2-ethylhexylamino)-2-butene-1,4-dione

Molecular formula:

C20H38N2O2

IUPAC Name:

(E)-1,4-Bis(2-ethylhexylamino)-2-butene-1,4-dione

impurity 2

Reference substance name:

1-(2-ethylhexyl)-1H-pyrrole-2,5-dione

Molecular formula:

C12H19NO2

IUPAC Name:

1-(2-ethylhexyl)-1H-pyrrole-2,5-dione

Test material form:

liquid

Details on test material:

Purity and characterisation analysis conducted on the following sample; Supplier: McLaughlin Gormley King ; Batch Number: AB9500

Specific details on test material used for the study:

MGK® 264
Lot No.: AA 7093
Purity: 95.2% MGK 264 (From CofA)

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

Animals
Adult, Hsd: Sprague Dawley® SD® rats were received from Harlan Sprague Dawley, Inc., Indianapolis, IN. Upon receipt, metal ear tags displaying unique identification numbers were used to individually identify the animals. Cage cards displaying at least the study number, animal number and sex were affixed to each cage.
Environment
The animal room temperature and relative humidity ranges were 56-72°F (13-22°C) and 14-61 %, 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 lightll2-hour dark cycle and room ventilation was set to produce 10-15 air changes/hour. The animal room temperature and relative humidity were recorded a minimum of once daily.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Doses:

Limit Test was dosed at 5000 mg/kg
Dose Levels of 175; 550; 1750 and 5000 mg/kg in the main study

No. of animals per sex per dose:

1 animal (female) for Limit Test
15 animals (all Female) for Up/Down Study

Control animals:

no

Details on study design:

The animals chosen for study use were randomly selected from healthy stock animals using a computerized random numbers table to avoid potential bias. All animals received a detailed pretest observation prior to dosing. Only healthy animals were chosen for study use. Females were nulliparous and nonpregnant. The female animals were approximately 9-12 weeks of age and weighed 176-206 grams prior to dosing.

On the day prior to dosing (day -1), the animals chosen for the study were weighed and fasted. On the day of dosing (day 0), the test article was administered orally as a single dose using a ball tipped stainless steel gavage needle attached to a syringe.

The animals were observed for clinical abnormalities a minimum of two times on study day 0 (post-dose) with the first observation within approximately 30 minutes after dosing and daily thereafter (days 1-14). A mortality check was performed twice daily, in the morning and afternoon.
Individual body weights were obtained for the test animals prior to fasting (day -I), prior to dosing on day 0 and on days 7 and 14. Animals found dead after day 0 were also weighed.

Statistics:

After each level was conducted, the short-term and long-term outcome (results) were input into the OECD 425 AOT Statistical Program. When the stopping criteria were engaged, the LD50 and the 95% confidence intervals were calculated using a computer program provided by the OECD (OECD 425 AOT program). Body weight means and standard deviations were calculated (as appropriate).
The results of the study were used to place the test article in the appropriate EPA Toxicity Category for labeling.

Results and discussion

Preliminary study:

Limit Test. 1 female animal dosed at 5000 mg/kg, due to mortality, the limit test was discontinued and an up/down study was initiated.

Effect levels

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

5 000 mg/kg bw

Based on:

test mat.

95% CL:

> 2 736 - < 6 360

Remarks on result:

other: Under the conditions of this test and based on the OECD 425 AOT Statistical Program, the acute oral LD50 of MGK® 264 was determined to be equal to 5000 mg/kg in the rat with a 95% confidence interval of 2736 to 6360.

Mortality:

Limit Test-
The female does at 5000 mg/kg for the limit test was found dead on day 1.

Up/Down test
For the 175 mg/kg dose level, no mortality occurred.
For the 550 mg/kg dose level, no mortality occurred.
For the 1750 mg/kg dose level, no mortality occurred.
For the 5000 mg/kg dose level, mortality occurred by study day 3. (5/7 animals were deceased)

Clinical signs:

For the 175 mg/kg dose level, no clinical observations were observed during the study.
For the 550 mg/kg dose level, no mortality occurred. Clinical observations during the study included transient incidences of congested breathing and salivation.
For the 1750 mg/kg dose level, no mortality occurred. Clinical observations during the study included transient incidences of congested breathing, few feces, feces small in size, salivation and dark material around the facial area. An additional observation of ocular lesion was noted in one animal that did not resolve by the time of scheduled necropsy on study day 14.
For the 5000 mg/kg dose level the most notable clinical abnormalities observed for the animals that died included decreased activity, wobbly gait, muscle spasms, impaired mobility, hyperextension of the limbs, rigid upon handling, intermittent tremors, congested breathing, labored breathing, slow breathing, shallow breathing, few feces, feces small in size, no feces, soft stools, urine stain, rough coat, cool to tough, hunched posture, piloerection, ocular discharge, eyelids partially closed, dilated pupils, pale eyes, salivation, dark material around the facial area, and decreased food consumption. For the animals that survived, the most notable clinical observations included transient incidences of decreased activity, wobbly gait, rigid upon handling, intermittent tremors, increased reactivity to handling, overt aggressiveness, circling motion (to the left), congested breathing, labored breathing, few feces, feces small in size, urine stain, rough coat, hunched posture, hairloss, piloerection, dehydration, unkempt appearance, swelling in the facial area, dark material around the facial area, salivation, and decreased food consumption.

Body weight:

For the 175 mg/kg dose level, body weight gain was noted for the animal during the test period.
For the 550 mglkg dose level, body weight gain was noted for the animal during the test period.
For the 1750 mglkg dose level, body weight gain was noted for all animals during the test period.
For the 5000 mg/kg dose level there were two surviving animals by day 14. Body weight loss was noted in 1/2 surviving animals during the study day 0 to 7 body weight interval. Body weight gain was noted for the other surviving animal during the test period.

Gross pathology:

For the 175 mg/kg dose level, no gross internal findings were observed at the time of scheduled necropsy on study day 14.
For the 550 mglkg dose level, no gross internal findings were observed at the time of scheduled necropsy on study day 14.
For the 1750 mglkg dose level, no gross internal findings were observed at the time of scheduled necropsy on study day 14.
For the 5000 mg/kg dose level, gross internal findings observed at necropsy included mottled lung, small thymus, distended stomach, and abnormal content in the small intestine.

Any other information on results incl. tables

Following are available in full in the attached report and as single pages in the background meterial attachments:

Table 1 - Summary of Mortality

Table 2 - Summary of Clinical Observations (2 pages)

Table 3 - Summary of Body Weight Data Grams

Table 4 - Summary of Gross Necropsy Observations (3 pages)

Table 5 - AOT results (2 pages)

Applicant's summary and conclusion

Interpretation of results:

other: No symbol and risk phrases are required according to EEC labelling regulations. (EC 1272/2008)

Conclusions:

According to the OECD Test Guideline 425 Acute Oral Toxicity Statistical Program, the LD50 of MGK 264 was determined to be equal to 5000 mg/kg with a 95% confidence interval of 2736 to 6360.

The acute oral median lethal dose (LD50) of the test material, in female Sprague-Dawley rats was found to be greater than 2000 mg/kg bodyweight. No symbol and risk phrases are required according to EEC labelling regulations. (EC 1272/2008)

Executive summary:

Under the conditions of this test and based on the OECD 425 AOT Statistical Program, the acute oral LD50 of MGK® 264 was determined to be equal to 5000 mg/kg in the rat with a 95% confidence interval of 2736 to 6360. The test article would be assigned an EPA-OPPTS Toxicity Category III for labeling.

According to the OECD Test Guideline 425 Acute Oral Toxicity Statistical Program, the LD50 of MGK 264 was determined to be equal to 5000 mg/kg with a 95% confidence interval of 2736 to 6360.

The acute oral median lethal dose (LD50) of the test material, in female Sprague-Dawley rats was found to be greater than 2000 mg/kg bodyweight. No symbol and risk phrases are required according to EEC labelling regulations. (EC 1272/2008)