Benzethonium chloride

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

February - August 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EPA OPP 81-1 (Acute Oral Toxicity)

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Benzethonium chloride

EC Number:

204-479-9

EC Name:

Benzethonium chloride

Cas Number:

121-54-0

Molecular formula:

C27H42NO2.Cl

IUPAC Name:

benzyldimethyl(2-{2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethoxy}ethyl)azanium chloride

Test material form:

solid: compact

Specific details on test material used for the study:

TEST MATERIAL
- Name: HYAMINE 1622
- Other ID (batch): Lonza TRCS Number 40109
- Source: Lonza Inc., Annandale, NJ
- Stability: Considered to be stable under conditions of shipment, storage, and use in this study.
- Purity: 99.3%
- Physical description: Fine white powder
- Storage Conditions: Room temperature
- Expiration date: October 26, 1996

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Test Animals:
Naive young adult male and female Sprague-Dawley derived albino rats of approximately the same age, weighing 181 to 273 grams on the day of dosing were used. The weight variation of the animals did not exceed ± 20% of the mean weight for each sex. The animals were purchased from Harlan Sprague Dawley, Inc. (Indianapolis, Indiana), a U.S.D.A. licensed supplier.

Housine and Animal Care:
All animals were acclimated to the Laboratory for at least six days before being used. Animals utilized for the range-finding phases were housed in groups of two/sex. Animals utilized for the range-finding phase which were incorporated into the definitive study also were housed in groups of two/sex. Animals utilized for the definitive study were housed in groups of five/sex. The additional animals included to complete the 800 mg/kg dose level were housed in groups of one/sex. All animals were housed in wire mesh suspension cages and were supplied Teklad 4% Mouse/Rat Diet and tap water ad libitum during both the acclimation and test periods except for withholding food (but not water) overnight prior to dosing. Food was withheld from the animals for a minimum of 15 hours, but not more than 18 hours, with exception that food was withheld for approximately 19 to 19.5 hours from animals utilized in the second range-finding screen and approximately 19.5 to 20.25 hours from animals utilized in the definitive study.
The animal room was maintained on a 12-hour light/12-hour dark cycle and at a temperature of 64-78°F and a relative humidity of 40-70%. Food and water were checked daily. There were no contaminants in either the feed or the water that were expected to affect the outcome of this study.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

Exposure of the rats was divided into two phases: the dose range-finding study phase and the definitive study phase. During both phases, a single dose ofthe test substance as a 10% w/v mixture in distilled water was administered orally by gavage using a stainless steel ball-tip cannula attached to a disposable syringe. Individual doses were calculated using post-fast body weights. Dose volumes for acute oral toxicity tests generally are limited to 10 ml/kg (maximum allowable volume) and 0.1 ml/rat (minimum volume for accurate delivery).

Doses:

1st PRETEST:
- 100, 400 and 800 mg/kg

2nd PRETEST:
- 100, 250, 500 and 800 mg/kg

MAIN TEST:
- 50, 104, 216, 450 and 800 mg/kg

No. of animals per sex per dose:

1st & 2nd PRETEST:
- Four animals (two males & two females)

MAIN TEST:
- Ten animals (five males & five females)

Control animals:

no

Details on study design:

An initial range-finding test was conducted with the test item. In this screening, the test substance was administered to three groups of two male and two female Sprague Dawley rats at dose levels of 100, 400 and 800 mg/kg. Based on the results of this screen, dose levels of 50, 104, 216, and 450 mg/kg were selected for the definitive study. During the definitive study, the test item was administered to groups of five male and five female Sprague Dawley rats. Following a single oral administration, the animals were observed for fourteen days. Due to the fact that only 50% mortality was observed in the highest dose group and because there was no clear dose response, additional range-finding work was conducted. During the second dose range-finding screen, the test item was administered to four groups oftwo male and two female Sprague Dawley rats at dose levels of 100, 250, 500 and 800 mg/kg.

Statistics:

None

Results and discussion

Preliminary study:

1st PRETEST:
- 100 mg/kg: 0% mortality
- 400 mg/kg: 75% mortality
- 800 mg/kg: 100% mortality

2nd PRETEST:
- 100 mg/kg: 25% mortality
- 250 mg/kg: 0% mortality
- 500 mg/kg: 25% mortality
- 800 mg/kg: 100% mortality

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

295 mg/kg bw

Based on:

test mat.

95% CL:

160 - 543

Mortality:

DOSE LEVELS:
- 50 mg/kg: 20%
- 104 mg/kg: 20%
- 216 mg/kg: 10%
- 450 mg/kg: 50%
- 800* mg/kg: 100%

* Represents the animals from both dose range-finding screens and the additional animals included to complete this dose level.

Clinical signs:

other: Treatment related clinical signs were observed at all levels tested: - 50 mg/kg: slightly sluggish, gasping and/or wheezing breathing, red stains on muzzle, fecal stains - 104 mg/kg: slightly sluggish, gasping and/or wheezing breathing, red stains on muzz

Gross pathology:

The gross necropsy findings in the animals that died during the observation period included signs of gastrointestinal irritation and signs typically found in agonal animals. The findings included: small amount of a dried red material on muzzle, lungs pale in color, stomach distended with gas and contained a moderate amount of a watery yellow brown feed-like pastel, small areas of intestines appeared reddened, lungs reddened, liver and spleen mottled, fecal stains, kidneys pale and congested, intestines yellow in color and contained a viscous yellow gel-like material, lungs motted, abdominal cavity contained a small amount of a clear red fluid, stomach with a watery yellow brown feed-like paste, areas of intestines hemorrhagic, intestines contained a viscous red fluid. No necropsy findings were noted in animals that survived until the end of the test.

Any other information on results incl. tables

The overall response observed in the two dose range-finding screens and in the definitive study showed that the dose response below 500 mg/kg was very shallow and that nothing would be gained by dosing additional animals at dose levels between 500 and 800 mg/kg. Therefore, two additional animals were dosed with the test item at 800 mg/kg. Both of these animals died following test substance administration. The data from these two animals were combined with the data from the 800 mg/kg dose levels in the two dose range-finding screens and used as the highest dose level in the definitive study.

Applicant's summary and conclusion

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

The oral LD50 value on rats was calculated to be 295 mg/kg with 95% Confidence Limits of 160 and 543 mg/kg. The test item is therefore classified as orally toxic, Cat. 3.

Executive summary:

This study was performed in accordance with EPA test guideliens no. 798.1175 to determine an estimated oral median lethal dose (LD50). In all phases of this study, the test item was administered as a 10% w/v mixture in distilled water. The study was designed to satisfy EPA Pesticide Assessment. An initial range-finding test was conducted. In this screen, the test substance was administered to three groups of two male and two female Sprague Dawley rats at dose levels of 100, 400 and 800 mg/kg. Due to unclear results, additional range-finding work was conducted. During the second dose range-finding screen, the test item was administered to four groups oftwo male and two female Sprague Dawley rats at dose levels of 100, 250, 500 and 800 mg/kg. Based on the results of the screening studies, dose levels of 50, 104, 216, and 450 mg/kg were selected for the definitive study. Four groups of five male and five female Sprague Dawley rats were tested. Following a single oral administration, the animals were observed for fourteen days.

Based on the mortality observed during the definitive study, the oral LD50 value was calculated to be 295 mg/kg with 95% Confidence Limits of 160 and 543 mg/kg. Treatment-related clinical signs were observed at all dose levels tested. All surviving animals appeared normal by Day 8. All surviving animals showed a positive weight gain during the study. The gross necropsy findings in animals that died during the study included signs of gastrointestinal irritation and signs typically found in agonal animals. No gross pathological changes were noted in animals which survived the observation period. Based on the results of this study, the test item needs to be classified as "Acute toxicity, Cat. 3, oral".