Hexylamine

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

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

Adequacy of study:

key study

Study period:

2005-10-12 through 2007-07-30

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study with acceptable restrictions. Please refer to section 13 (read across statement).

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Reference 2

Reference Type:

publication

Title:

Unnamed

Year:

2007

Report date:

2007

Reference 3

Reference Type:

other: TSCA 8(e)

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Octylammonium chloride

EC Number:

205-574-8

EC Name:

Octylammonium chloride

Cas Number:

142-95-0

IUPAC Name:

octan-1-aminium chloride

Test animals

Species:

rat

Strain:

other: Crl:CD (SD) IGS BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Inc., Raleigh, NC
- Age at study initiation: 81 days
- Weight at study initiation: 355.2 - 450.2 grams (males) and 196.3 - 309.0 grams (females)
- Fasting period before study: 15 hours (only animals from which samples were taken for clinical pathology evaluation: hematology, clinical chemistry, and urinalysis)
- Housing: individually during non-mating periods
- Diet: PMI Nutrition International, Certified Rodent LabDiet 5002 ad libitum, except when fasted
- Water: ad libitum
- Acclimation period: 28 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-26
- Humidity (%): 30-70
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
- mixing of test substance with NanoPure water (procedure documented in the study records)
- pH was adjusted to values between 4.0 an 6.0 prior to dosing
- Storage: refrigerated up to 7 days of the low, intermediate,and high dose solution
- stability: demonstrated (Appendix C)

- Dose volume: 4 mL/kg bw

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Dosing samples were diluted to a concentration of 0.100 mg/mL; the pH was adjusted with 8 N NaOH, the samples were then extracted with toluene containing decylamine as internal standard. Sample analysis was performed using Gas Chromatography (cf. Appendix C for details).

Duration of treatment / exposure:

Males: 47-48 days/Females: 42-46 days

Frequency of treatment:

daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0 (Vehicle), 37.5, 75, and 150/100 mg/kg/day
Basis:
actual ingested

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: based on the results of two range-finding studies

Positive control:

not required

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least daily

DETAILED CLINICAL OBSERVATIONS: Yes

BODY WEIGHT: Yes
- Time schedule for examinations: once during pretets (baseline) and weekly thereafter. Observations included (but were not limited to) evaluation of fur, skin, eyes, mucous membranes, occurrence of secretions and excretions, autonomic nervous system activity (lacrimation, piloerection, and unusual respiratory pattern), changes in gait, posture, response to handling, presence of clonic, tonic, stereotypical, or bizarre behavior.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): not applicable

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: test days 13-14; coagulation at study termination, test days 42-47
- Anaesthetic used for blood collection: Yes (carbon dioxide)
- Animals fasted: Yes
- How many animals: all F0 animals

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: test days 13-14
- Animals fasted: Yes
- How many animals: all F0 animals

URINALYSIS: Yes
- Time schedule for collection of urine: test days 13-14
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes

NEUROBEHAVIOURAL EXAMINATION: Yes
- Prior to tretment: test days 7-8 (males and females)
- Prior to the end of the premating period: test days 12-13 (males and females)
- No. of replicates: 4 for each evaluation
- Dose groups that were examined: all groups, all animals

Sacrifice and pathology:

GROSS PATHOLOGY: Yes

HISTOPATHOLOGY: Yes
- Reproductive organs: all (12/sex/dose) control and high dose animals
- Other tissues: from randomly selected animals (5/sex/dose)
- Trachea: from all adult rats
- Pups: no microscopical examinations

Statistics:

Primarily, Levene's test for homogeneity, one-way analysis of variance, Dunnett's test, Kruskal-Wallis test, Dunn's test and Cochran-Armitage test for trend

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Food efficiency:

effects observed, treatment-related

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

not specified

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

effects observed, treatment-related

Behaviour (functional findings):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

no effects observed

Details on results:

EFFECTS BY DOSE LEVEL:

Low dose group: 37.5 mg/kg bw/day:
F0 parental animals
CLINICAL EXAMINATIONS/CLINICAL PATHOLOGY/URINALYSIS/PATHOLOGY
-statistically significant reductions in body weights (-6%) and body weight gain (-17%) in males from the first week to the end of the study
- slight (not statistically significant) reductions in body weights (-2%/-8%) and body weight gain (-48%/-14%) in females as compared with controls, during premating and gestation, respectively.
-statistically significant reductions in food consumption (-6%) in males during premating
-slight (not statistically significant) reductions in food consumption in females during premating (-8%) and gestation (-12%)
-statistically significant decrease in hemoglobin concentration on day 14 in females, minimal (-4%), not dose-related
-minimal tracheal lesions in males, dosing-related, likely the result of topical exposure to the test substance


Intermediate dose group, 75 mg/kg bw/day:
F0 parental animals
CLINICAL EXAMINATIONS/CLINICAL PATHOLOGY/URINALYSIS/PATHOLOGY
-salivation in 7/12 males and in 1/12 females during premating
-statistically significant reductions in body weights (-6%) and body weight gain (-20%), as compared with controls, in males from the first week to the end of the study
-slight (not statistically significant) reductions in body weights (-3%/-6%) and body weight gain (-27%/-10%) as compared with controls, in females during premating and gestation, respectively
-statistically significant reductions in food consumption (-8%) in males during premating
-slight (not statistically significant) reductions in food consumption in females during premating (-9%) and gestation (-12%)
-minimal tracheal lesions in males and females, dosing-related, likely the result of topical exposure to the test substance


High dose group, 150/100 mg/kg bw/day:
F0 parental animals:
MORTALITY:
Two female rats and one male rat in the150 mg/kg/day group were found dead on test days 8 to 12. Autopsy suggested a dosing accident aggravated by the irritation from the test substance.

CLINICAL EXAMINATIONS/CLINICAL PATHOLOGY/URINALYSIS/PATHOLOGY
-salivation in 12/12 male animals, in 12/12 females during premating, and in 2/12 females during gestation
-irregular respiration, lung noise, and fur-staining (face and nose). Diarrhea, gasping, hunched-over posture, weakness, and abnormal gait/mobility in one male
-statistically significant reductions in body weights (-12%) and body weight gain (-43%) as compared with controls, in males from the first week to the end of the study
-slight (not statistically significant) reductions in body weights (-2%/-7%) and body weight gain(-41%/-11%) as compared with controls, in females during premating and gestation, respectively
-statistically significant reductions in food consumption (-13%) in males during premating
-slight (not statistically significant) reductions in food consumption in females during premating (-8%) and gestation (-11%)
-minimal to mild tracheal lesions in males and females, dosing-related, likely the result of topical exposure to the test substance
-statistically significant decrease in mean cell hemoglobin concentration (-1%) on day 14 in females, without associated changes in other white blood cell parameters, not treatment-related
-statistically significant increase in eosinophils (200%) on day 13 in males, without associated changes in other white blood cell parameters or
correlative histologic changes, possibly treatment-related, but not considered adverse
-statistically significant decrease in absolute heart weight (-13%) as compared with controls, in males accompanied by slight (not significant)
decreases in most other absolute and relative organ weights in males and females, all without microscopic changes and probably related to overall decrease in body weights
-statistically significant increase in relative adrenal gland (36%) and testes (14%) weights in males, without microscopic changes

Effect levels

Dose descriptor:

NOAEL

Effect level:

ca. 100 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: clinical signs; mortality; body weight; food consumption; food efficiency; haematology; clinical chemistry; urinalysis; gross pathology; organ weights; histopathology

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Body weight

Compared to controls, body weight was slightly reduced in treated groups, reaching a level of statistical significance in males. The biological relevance is, however low, because the changes are small and are paralleled by reductions in food consumption which can explain the body weight reductions, rather than test substance-related toxicity.

Table 1: Bodyweights

	Males			Females
Dose (mg/kg bw/day)	37.5	75	150/100	37.5	75	150/100
Reduction body weight (%)	-6*	-6*	-12*	-2 (premating) -8 (gestation)	-2 (premating) -6 (gestation)	-2 (premating) -7 (gestation)
Reduction food consumption (%)	-6*	-8*	-13*	-8 (premating) -12 (gestation)	-9 (premating) -12 (gestation)	-8 (premating) -11 (gestation)

Clinical signs

The incidence of clinical signs was as follows:

 

Table 2: clinical signs

	Male				Female
Dose (mg/kg bw/day)	0	37.5	75	150/100	0	37.5	75	150/100
Number of rats at sacrifice	12	12	12	11	12	12	12	10
Weak, hunched position	0	0	0	1	0	0	0	1
Lung noise	0	0	0	3	0	0	0	1
Salivation	0	0	7	12	0	0	1	12

 

 

Microscopic Findings

Dosing-related microscopic findings were observed in the trachea (mucosal metaplasia, hyperplasia, and inflammation) of males and females at all dose levels. However, these tracheal lesions were interpreted to be the result of inadvertent direct exposure of the trachea to the test substance during dosing and not the effect of gavage exposure. Therefore, these microscopic findings were not test substance-related in the context of a gavage study.

 

Table 3: Incidences of Dosing-Related Microscopic Findings in Male and Female Rats

	Male				Female
Dose (mg/kg bw/day)	0	37.5	75	150/100	0	37.5	75	150/100
Number of rats at sacrifice	12	12	12	11	12	12	12	10
Trachea
Metaplasia, mucosal	1	4	11	7	1	1	5	6
Hyperplasia, mucosal	0	1	1	0	0	0	1	0
Inflammation, mucosal	0	0	0	0	0	0	1	1

 

The authors interpreted the underlined to be dosing-related increases in microscopic findings.

 

 

Trachea

Squamous metaplasia of the proximal to mid-cervical trachea was observed in more than half of the male (18/23) and female (11/22) rats given >/= 75 mg/kg/day and in one-third (4/12) of the male rats given 37.5 mg/kg/day of the test substance. All cases were graded as minimal (grade 1 of 4), except for two males (one each at 75 and 150/100 mg/kg/day) that were graded as mild

The metaplasia consisted of the partial replacement of the normal ciliated pseudostratified columnar epithelium (i.e., respiratory epithelium) on the ventral and lateral aspects of the tracheal mucosa with deciliated round and/or flattened epithelial cells resembling mucous membrane. In two males (one each at 37.5 and 75 mg/kg/day), the metaplasia was associated with minimal hyperplasia. In two females (one each at 75 and 150/100 mg/kg/day), the metaplasia was associated with minimal inflammation.

 The minimal to mild squamous metaplasia, and associated hyperplasia and inflammation, was probably the result of transient topical exposure of the tracheal mucosa to the test substance following gavage administration. These minimal to mild lesions in surviving rats contrast with the moderate (grade 3 of 4) to severe (grade 4 of 4) tracheal ulceration and inflammation observed in the two decedent females that died following accidental administration of the test substance to the trachea.

 The minimal to mild metaplasia observed in the surviving rats was interpreted to be a nonadverse adaptive response, most likely reversible, which was due to transient esophageal reflux or imperfect dosing. The four incidences of minimal tracheal inflammation or hyperplasia were also considered to be artifacts of the dosing procedure rather than test-substance related effects.

 

Other

All other microscopic observations in this study were consistent with normal background lesions in rats of this age and strain.

 

One neoplasm occurred in this study. A malignant renal mesenchymal tumor was observed in a kidney from a high-dose female rat (Animal Number 805). Although this is an uncommon neoplasm, the individual occurrence was considered to be incidental and not test substance related.