Registration Dossier

n-Butylamine is corrosive. A concentration dependent increase in incidence and severity of changes in the epithelium of the anterior nasal cavity occurred. The LOAEC local for irritation of the upper respiratory tract was 51 mg/m³ (17 mL/m³).

However, no treatment related clinical findings were observed up to the highest concentration so that a NOAEC of 460 mg/m³ could be derived for systemic effects.

Endpoint conclusion:

no study available

Reference

Endpoint:

short-term repeated dose toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

OECD 414 guideline study which does not address all aspects relevant for repeated dose toxicity

Reason / purpose for cross-reference:

reference to same study

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

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

effects observed, treatment-related

Neuropathological findings:

not examined

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).

Key result

Dose descriptor:

LOAEC

Effect level:

51 mg/m³ air (analytical)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Histopathology: local effects (nasal irritation)

Dose descriptor:

NOAEC

Effect level:

< 51 mg/m³ air (analytical)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Histopathology: local effects (nasal irritation)

Key result

Dose descriptor:

NOAEC

Effect level:

460 mg/m³ air (analytical)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: systemic toxicity

Key result

Critical effects observed:

not specified

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

	Percentage of dams (n = 10) showing lesions exposed to the following concentrations in ppm [mg/m³], nominal
Histopathological findings	0	17 [50]	50 [150]	150 [450]
Squamous cell metaplasia	0	10	50	100
Purulent to mixed inflammatory cell infiltration	0	30	90	100
Focal necrosis of nasal mucosa	0	0	0	50
Necrosis of nasal bone	0	0	0	10

Conclusions:

Under the conditions of this study, the LOAEC for irritation of the upper respiratory tract was 51 mg/m3. In the absence of systemic toxicity a NOAEC of 460 mg/m3 can be determined.

Executive summary:

Twenty-five mated female Wistar rats per test group were whole-body exposed to dynamic atmospheres of Mono-n-Butylamin vapors for 6 hours per day on day 6 through day 19 post coitum (p.c.; 14 exposures). The target concentrations were 50, 150 and 450 mg/m 3. A concurrent control group was exposed to clean air.

No treatment related clinical findings were observed. A concentration dependent increase in incidence and severity of changes in the epithelium of the anterior nasal cavity (necrosis, hyper- and metaplasia, inflammatory cell infiltration) occurred. Under the conditions of this prenatal developmental toxicity study, the inhalation exposure of pregnant Wistar rats to vapours of Mono-n-Butylamin from implantation to one day prior to the expected day of parturition (days 6 - 19 p.c.) elicited maternal toxicity at all tested concentrations. Maternal toxicity was substantiated by changes of the respiratory epithelium in the nasal cavity.

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

460 mg/m³

Study duration:

subacute

Species:

rat

Quality of whole database:

Repeated dose toxicity was examined in the context of a developmental toxicity study and the data was considered sufficient for evaluation of this endpoint (see below).

Reference

Endpoint:

short-term repeated dose toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

OECD 414 guideline study which does not address all aspects relevant for repeated dose toxicity

Reason / purpose for cross-reference:

reference to same study

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

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

effects observed, treatment-related

Neuropathological findings:

not examined

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).

Key result

Dose descriptor:

LOAEC

Effect level:

51 mg/m³ air (analytical)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Histopathology: local effects (nasal irritation)

Dose descriptor:

NOAEC

Effect level:

< 51 mg/m³ air (analytical)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Histopathology: local effects (nasal irritation)

Key result

Dose descriptor:

NOAEC

Effect level:

460 mg/m³ air (analytical)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: systemic toxicity

Key result

Critical effects observed:

not specified

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

	Percentage of dams (n = 10) showing lesions exposed to the following concentrations in ppm [mg/m³], nominal
Histopathological findings	0	17 [50]	50 [150]	150 [450]
Squamous cell metaplasia	0	10	50	100
Purulent to mixed inflammatory cell infiltration	0	30	90	100
Focal necrosis of nasal mucosa	0	0	0	50
Necrosis of nasal bone	0	0	0	10

Conclusions:

Under the conditions of this study, the LOAEC for irritation of the upper respiratory tract was 51 mg/m3. In the absence of systemic toxicity a NOAEC of 460 mg/m3 can be determined.

Executive summary:

Twenty-five mated female Wistar rats per test group were whole-body exposed to dynamic atmospheres of Mono-n-Butylamin vapors for 6 hours per day on day 6 through day 19 post coitum (p.c.; 14 exposures). The target concentrations were 50, 150 and 450 mg/m 3. A concurrent control group was exposed to clean air.

No treatment related clinical findings were observed. A concentration dependent increase in incidence and severity of changes in the epithelium of the anterior nasal cavity (necrosis, hyper- and metaplasia, inflammatory cell infiltration) occurred. Under the conditions of this prenatal developmental toxicity study, the inhalation exposure of pregnant Wistar rats to vapours of Mono-n-Butylamin from implantation to one day prior to the expected day of parturition (days 6 - 19 p.c.) elicited maternal toxicity at all tested concentrations. Maternal toxicity was substantiated by changes of the respiratory epithelium in the nasal cavity.

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LOAEC

51 mg/m³

Study duration:

subacute

Species:

rat

Quality of whole database:

Effects in the upper respiratory tract (the most sensitive target) were observed at the lowest exposure concentration.

Endpoint conclusion:

no study available

Endpoint conclusion:

no study available

In the absence of any information on species specific modes of action the available information is regarded as relevant for humans.

The most appropriate route of exposure is inhalation. There is no guideline repeated dose toxicity study, e.g. according to OECD guidelines 412, 413, available.

However, information is available from a developmental study (BASF AG 2001/2002), which is suitable to assess the inhalation toxicity and was selected therefore as key study:

The most relevant effect of n-butylamine is its irritating/corrosive effect on skin and mucous membranes. Effects in the upper respiratory tract (the most sensitive target) were observed at the lowest exposure concentration of 51 mg/m3 in the developmental study (BASF AG 2001/2002) already after 14 days of exposure.

Effects in other organs were not examined, but the absence of systemic responses at this and even higher exposure concentration can be reasonably assumed:

1) As the amines are readily metabolised to biogenic molecules, e.g. butyric acid, systemic effects are not assumed to occur at concentrations which already provoke irritation.

2) A calculation of resulting body doses of the highest exposure concentration (inhalation) with an oral study with pregnant rats receiving the hydrochloride salt of butylamine (see Developmental toxicity, IUCLID 7.8.2) confirm this assumption: An exposure of rats to 460 mg/m3 (6 h/d; analytical), which is severely irritating, corresponds to a body dose of 450 mg/m3 x 0.29 m3/kg bw = 130.5 mg/kg bw (caluclation according to ECHA guidance R.8). The maternal NOAEL in the oral study was 460 mg/kg bw/d hydrochloride, corresponding to 265 mg/kg bw/d amine base, i.e. a factor of about 2 higher than the highest body dose resulting from inhalation exposure.

Therefore, no systemic effects are expected at inhalation concentrations up to 460 mg/m3 (6 h/d; analytical), the highest test concentration in the inhalation study, and a fortiori not at the LOAEC for irritation of 51 mg/m3.

Classification with respect to STOT RE endpoints for maternal effects in a developmental toxicity study according to Regulation (EC) No 1272/2008 is not necessary, as no systemic toxic effects were observed after repeated exposure in a developmental toxicity study (14 exposures). The only effects observed were local effects in the respiratory tract which are already considered in the STOT SE 3 classification.