Hexylamine

Endpoint summary

Description of key information

oral:
In a read across study the NOAEL  for octylammonium chloride after repeated oral application was determined to be 100 mg/kg bw in rats.
inhalation:
The LOAEC for repeated inhalation of the read across substance butylamine was determined to be 51 mg/m3 in rats.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

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).

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

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

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

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

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

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

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

Critical effects observed:

not specified

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.

 

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

100 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

OECD Guideline Studies, sufficient for assessment

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and Guideline study Please refer to section 13 (read across statement).

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 412 (Subacute Inhalation Toxicity: 28-Day Study)

Deviations:

yes

Remarks:

according to OECD Guideline 414 (Prenatal Developmental Toxicity Study) [see 7.8.2]

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: K. Thomae GmbH/Boehringer Ingelheim, Biberach/Germany
- Age at study initiation: approx. 70 d
- Weight at study initiation: 198 - 246 g
- Housing: single
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 5 d before mating


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24
- Humidity (%): 30 - 70
- Photoperiod (hrs dark / hrs light): 12 / 12

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus:glass-steel inhalation exposure chamber, 1.4 m3, space for 6x6 cages
- Method of holding animals in test chamber: 1 animal/cage
- Source and rate of air: charcoal-filtered air
- System of generating particulates/aerosols: In a thermostated vaporiser (25 - 35 °C), the vapor-air mixture was generated by spraying the TS
with compressed air into a counter current of conditioned air, followed by further mixing with air to achieve required
exposure concentrations.
- Temperature, humidity, pressure in air chamber: 21.2 - 22.5 °C; 50.5 - 62.0 %
- Air change rate: Air changes: 20/hour


TEST ATMOSPHERE
- Brief description of analytical method used: GC/FID after absorption in DMF
- Samples taken from breathing zone: yes

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

- Method: GC with FID detection
- Sampling time: 2 times during each exposure (for controls 2 times during the study)

Duration of treatment / exposure:

14 d (6 - 19 day of gestation)

Frequency of treatment:

6 h/d

Remarks:

Doses / Concentrations:
51.4 +-2.2; 151.8 +-9.2; and 460 +-17.5 mg/m3 (= 17, 50.1, and 151.8 mL/m3)
Basis:
analytical conc.

No. of animals per sex per dose:

20 - 24 pregnant female rats

Control animals:

yes, concurrent no treatment

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: 3x during exposure, other days 1x

BODY WEIGHT: Yes
- Time schedule for examinations: on day 1, 3, 6, 8, 10, 13, 15, 17, 19 and 20

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Organs examined: ovary, uterus, placenta
- macroscopy of dams
- histopathological examination of 4 sections of the nasal cavity

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not examined

Details on results:

- Mortality: none
- Body weight: no treatment related effects
- Clinical signs: no treatment related effects
- Gross pathology incidence and severity: no treatment related effects [incidental congestion, oedema and/or marginal emphysema of the lungs (due to method of sacrifice)
- Histopathology incidence and severity: anterior nasal section showing squamous metaplasia, inflammatory cells and hyperplasia of transitional cells at all concentrations (dose dependent effect). At 450 mg/m3, necrosis of the nasal mucosa (5 animals) and the underlying nasal bone (1 animal).

Dose descriptor:

NOAEC

Effect level:

> 17 ppm

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Histopathology: nasal irritation

Dose descriptor:

NOAEC

Effect level:

> 51 mg/m³ air (analytical)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Histopathology: nasal irritation

Dose descriptor:

LOAEC

Effect level:

51 mg/m³ air (analytical)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Histopathology: nasal irritation

Critical effects observed:

not specified

Table 1: Nasal irritation in dams following inhalation exposure to n-butylamine during gestation (14 d)

	Percentage of dams showing lesions exposed to the following concentrations in ppm [mg/m^3], nominal
Histopathological findings	0	17 [50]	50 [150]	150 [450]
Squamous cell metaplasia	No data	10	50	100
Purulent to mixed inflammatory cell infiltration	No data	30	90	100
Focal necrosis of nasal mucosa	No data	0	0	50
Necrosis of nasal bone	No data	0	0	10

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LOAEC

51 mg/m³

Study duration:

subacute

Species:

rat

Quality of whole database:

GLP guideline study with acceptable restrictions and summary of Guideline study

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Oral

A read across study is available in which Octylamine-HCl was examined for its potential for repeated dose toxicity, developmental and neurotoxicity in a combined OECD TG 422 study under GLP conditions. The dose levels used (0, 37.5, 75, an 100/150 mg/kg bw/day; oral gavage; 12 rats/sex/dose) were selected based on the results of two range finding studies, one in the range 100-1000 mg/kg bw/day, and one in the range 3-100 mg/kg bw/day. The high dose group was initially dosed at 150 mg/kg bw/day, but this was lowered 100 mg/kg bw/day by test day 14 because two mortalities were seen in this group. Therefore, this dose level is called “100/150 mg/kg bw/day”. It should however be mentioned that subsequent examinations revealed that these mortalities resulted from maldosing and were not related to the test substance. Thus, there were no substance-related mortalities in this study, and with few exceptions there were no changes in clinical signs of toxicity, clinic-chemical parameters, hematology, urinalysis, gross observations, organ weights, and histopathology that were attributable to the test substance and of statistical or biological relevance. Effects on male and female body weight, clinical signs including salivation, and changes in the trachea were observed as follows: Minimal to mild squamous metaplasia, and associated hyperplasia and inflammation, was seen in all treated groups. 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. Lung noise was observed only in high dose rats. Weak animals showed also lung noise or noisy respiration. Maldosing or reflux cannot be excluded to be responsible for lung noise, as tracheal metaplasia was seen in 2 of the 4 animals which showed lung noise. Salivation in mid dose males was seen on individual days scattered over the entire study period, and lasted only one day (e.g. day 2-2; day 36-36; etc.). At the high dose, salivation was seen in all animals and persisted for several days. This could result from bad taste, but the biological relevance is, however, not clear. 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. Based on the above, and taking results of the range-finding studies into consideration, it is concluded that the test substance (octylamine hydrochloride; pH adjusted to 4.0-6.0; dose volume 4 mL/kg bw) was irritating. It caused respiratory problems and tracheal irritation after maldosing and/or reflux. The food intake was slightly reduced and led to slight reductions of body weight and body weight gain. The observed clinical signs and slightly reduced body weights are therefore considered to be secondary, rather than to reflect systemic toxicity of the test substance. Therefore, the NOAEL for systemic toxicity was considered to be 100 mg/kg bw/day under the conditions of this study.

Inhalation

In a 14 days repeated dose inhalation study on rats, 20-24 pregnant female animals were exposed to concentrations of 51.4 +/-2.2; 151.8 +/-9.2; and 460 +/-17.5 mg/m3 (analytically verified) for 6 hours/day to the read across substance butylamine. No effects on mortality and body weight and no clinical signs were observed. Nasal irritation was observed in all dose groups. Based on these results, the LOAEC was determined to be 51 mg/m3 (17 ppm) air and the NOAC was determined to be >17 ppm.

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
Only one study availabale

Justification for selection of repeated dose toxicity inhalation - systemic effects endpoint:
Only one study available

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. As a result the substance is not considered to be classified for repeated dose toxicity under Regulation (EC) No 1272/2008, as amended for the sixth time in Directive EC 605/2014.

Dangerous Substance Directive (67/548/EEC)

The available study is considered reliable and suitable for classification purposes under 67/548/EEC. As a result the substance is not considered to be classified for repeated dose toxicity under Directive 67/548/EEC, as amended for the 31st time in Directive 2009/2/EG.