Diethylammonium chloride

Endpoint summary

Description of key information

RA from CAS 75-50-3:

NOAEL systemic (oral, subacute, rat, OECD 422) = 40 mg/kg bw/day

RA from CAS 109-89-7:

NOAEC systemic (inhalation, subchronic, mouse and rat, similar to OECD 413): 16 ppm

NOAEC local (inhalation, subchronic, mouse and rat, similar to OECD 413): 16 ppm

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

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

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

(no data on detailed clinical observation, sensory reactivity to stimuli, assessment of grip strength, and motor activity)

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

(no data on detailed clinical observation, sensory reactivity to stimuli, assessment of grip strength, and motor activity)

Qualifier:

according to guideline

Guideline:

other: OPPTS 870-3650

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

-Age: 9 weeks

Route of administration:

oral: gavage

Duration of treatment / exposure:

Males: 42 days; Females: 2 weeks prior to breeding, continuing through breeding (2 weeks), gestation (3 weeks), lactation (4 days), and until the day of necropsy (test day 40 or 54).

Frequency of treatment:

Daily

Dose / conc.:

8 mg/kg bw/day (nominal)

Dose / conc.:

40 mg/kg bw/day (nominal)

Dose / conc.:

200 mg/kg bw/day (nominal)

No. of animals per sex per dose:

13

Control animals:

yes, concurrent vehicle

Observations and examinations performed and frequency:

- General condition was observed at least once a day during breeding and at least twice a day before and after dosing over the administration period.

- Body weights for males were determined on days 1, 7, 14, 21, 28, 35, 42 and on the day of necropsy. Body weights were determined for all females on days 1, 7, 14. Females who took time before mating were weighed on days 35 and 42. Females who copulated were weighed on pregnancy days 0, 7, 14 and 20. Females who delivered were weighed on nursing days 0, 4, and on the day of necropsy. Females who copulated but did not deliver were weighed on the equivalent of pregnancy day 25 (day of necropsy).

- Food consumption was measured on days 1, 7, 13, 29, 35 and 41 for males, and on days 1, 7, and 13 for all females. Females with unconfirmed copulation were measured for food consumption on days 29, 35 and 41.

- Urinalysis was conducted on 5 rats/sex/dose level at week 6.

- Hematology and clinical chemistry: Males prior to necropsy and on the  following day after day 42 administration; Females prior to necropsy: females who delivered-following nursing day 4, females who mated but did  not deliver-equivalent of pregnancy day 25, and  females who did not mate- following day 54 of administration.

Sacrifice and pathology:

ORGANS EXAMINED AT NECROPSY (MACROSCOPIC AND MICROSCOPIC):
-Macroscopic: organ weights: testes and epididymides; females, ovaries and uteri were extracted, the pregnancy corpora lutea number of the ovary was counted under the stereoscopic microscope, the implantation number of the uterus was counted, and the implantation rate ((implantation number/pregnancy corpora lutea number) x 100) was calculated.
-Microscopic: 5 animals/sex/control and high dose group- sperm and prostrate ventral lobes of all males and vagina, ovaries and uteri of all females; also testes, epididymides, ovaries found to be abnormal during pathologic examinations were all examined histopathologically.

Statistics:

Mann-Whitney U Test (2-tailed) and Fisher's Exact Test (1-tailed): histopathological examinations,
Dunnett's Multiple Comparison Test (significance level=5%): body weight, food consumption, hematology, clinical chemistry and organ weights

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

-Clinical signs prior to death
200 mg/kg bw/day: The male that died on Day 25 showed salivation, emaciation, abnormal breathing noise and dyspnea from administration day 19, and vulval peripheral fur soiled and loose passage were observed from the day before the death. The male that died on Day 42 showed salivation, emaciation, abnormal breathing noise, dyspnea, a drop in body temperature, faded auricle, tottering and brown soil around the nose were observed from administration day 10, although discontinuously. The female rat that died on pregnancy day 22, was observed with salivation and abnormal breathing noise sporadically from administration day 11.

-Clinical signs in surviving animals:
200 mg/kg bw/day:
Males: salivation 10/13, abnormal breathing noise 3/13, and decreased contact response 1/13;
Females: salivation 10/13, abnormal breathing noise 3/13, and emaciation 1/13.

40 mg/kg/day: no abnormalities

Mortality:

mortality observed, treatment-related

Description (incidence):

-Mortality and time to death: 1 male given 200 mg/kg/day died on day 25, 1 male given 200 mg/kg/day died on day 42 and 1 female died on pregnancy day 22 (administration day 38)

Body weight and weight changes:

no effects observed

Description (incidence and severity):

Males
No significant differences in body weights at 200 mg/kg bw/day; however, body weight gains were decreased when compared to controls. There were no significant differences in body weight or body weight gains in males administered 40 mg/kg bw/day.
Females
No significant differences in body weight or body weight gains.

Food consumption and compound intake (if feeding study):

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

40 mg/kg bw/day: significant increase in urea nitrogen

Urinalysis findings:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Details on results:

Daily oral administration of trimethylamine by gavage resulted in the death of two males and 1 female administered 200 mg/kg bw/day. Abnormal breathing noise, salivation immediately after the administration, ulcers and inflammatory changes in the stomach and intestinal tracts, squamous hyperplasia and edema in submucosa were observed in both males and females in the 200 mg/kg bw/day group. An inhibitory tendency in body weight increase, decrease in food consumption, total protein concentration and albumin concentration were also observed in the males in the same group.
There was no effect of trimethylamine administration on body weights and food consumption of the females and on organ weights, urine examination and hematological examination results in the males and females. Therefore it was inferred that the general toxicological NOAEL (No Observed Adverse Effect Level) is 40 mg/kg bw/day.

Key result

Dose descriptor:

NOAEL

Effect level:

40 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Treatment-related and adverse effects (clinical signs and mortality) observed at 200 mg/kg bw/day

Critical effects observed:

not specified

Conclusions:

The NOAEL for systemic toxicity was considered to be 40 mg/kg bw/day based on abnormal breathing noise and salivation immediately after the administration, ulcers and inflammatory changes in the stomach and intestinal tracts, squamous hyperplasia and edema in submucosa, which were observed in both males and females in the 200 mg/kg bw/day group. These local effects (ulcers, inflammation) at sites of contact (stomach, intestines) were considered to be due to corrosive properties of substance.

Reference 2

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

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

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

refer to analogue justification provided in IUCLID section 13

Reason / purpose for cross-reference:

read-across source

Key result

Dose descriptor:

NOAEL

Effect level:

40 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Treatment-related and adverse effects (clinical signs and mortality) observed at 200 mg/kg bw/day

Critical effects observed:

not specified

Conclusions:

The NOAEL for systemic toxicity was considered to be 40 mg/kg bw/day based on abnormal breathing noise and salivation immediately after the administration, ulcers and inflammatory changes in the stomach and intestinal tracts, squamous hyperplasia and edema in submucosa, which were observed in both males and females in the 200 mg/kg bw/day group. These local effects (ulcers, inflammation) at sites of contact (stomach, intestines) were considered to be due to corrosive properties of substance.
Applying the RA-approach similar results are expected for the target substance.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

40 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

The available information comprises an adequate and reliable study (Klimisch score 2) from a reference substance with similar structure and intrinsic properties. Read-across is justified based on structural similarities (refer to endpoint discussion for further details). The selected study is thus sufficient to fulfil the standard information requirements set out in Annex VIII, 8.7, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006.

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Scientific study according to NTP standard protocol that fully meets documentation requirements.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Taconic Farms, Inc. (Germantown, NY)
- Age at study initiation: approximately 6 weeks
- Weight at study initiation: males: 110 g (mean), female: 93 g (mean)
- Housing: individually in stainless steel wire bottom (Lab Products, Inc., Seaford, DE), changed weekly and rotated daily
- Diet: NTP-2000 irradiated wafers (Zeigler Brothers, Inc., Gardners, PA), available ad libitum, except during exposure periods
- Water: Tap water (Richland municipal supply) via automatic watering system (Edstrom Industries, Waterford, WI), available ad libitum
- Acclimation period: 12 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±3 °C (72°±3 °F)
- Humidity (%): 50% ± 15%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Remarks:

inhalation chamber

Vehicle:

other: unchanged

Details on inhalation exposure:

Diethylamine was pumped onto glass beads in a heated glass column where it was vaporized. Heated nitrogen flowed through the column and carried the vapor into a short vapor distribution manifold. Concentration in the manifold was determined by the chemical pump rate and nitrogen flow rate. The pressure in the distribution manifold was kept fixed to ensure constant flow through the manifold and into all chambers as the flow of vapor to each chamber was adjusted.
Individual Teflon® delivery lines carried the vapor from the manifold to three-way exposure valves at the chamber inlets. The exposure valves diverted vapor delivery to the exposure chamber exhaust until the generation system was stable and exposures were ready to proceed. A metering valve with a flow indicator at the manifold controlled the flow rate to each chamber. To initiate exposure, the chamber exposure valves were rotated to allow the vapor to flow to each exposure chamber inlet duct where it was further diluted with HEPA®-filtered, conditioned air to achieve the desired exposure concentration.
The study laboratory designed the inhalation exposure chamber (Harford Systems Division of Lab Products, Inc., Aberdeen, MD) so that uniform vapor concen-trations could be maintained throughout the chamber with the catch pans in place. The total active mixing volume of each chamber was 1.7 m3. A small particle detector was used with and without animals in the exposure chambers to ensure that diethylamine vapor, and not aerosol, was produced. No particle counts above the minimum resolvable level (approximately 200 particles/cm3) were detected.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The on-line gas chromatograph was checked throughout the day for instrument drift against an on-line standard of diethylamine in nitrogen supplied by a standard generator. The on-line gas chromatograph was calibrated by a comparison of chamber concentration data to data from grade samples that were collected with acrylic ester adsorbent gas sampling tubes, extracted with methylene chloride containing triethylamine as an internal standard, and analyzed using an off-line gas chromatograph. Known values of chamber atmosphere were sampled at a constant flow rate ensured by a calibrated orifice. The off-line gas chromatograph was calibrated with gravimetrically prepared standards of diethylamine and the internal standard (triethylamine) in methylene chloride.

Duration of treatment / exposure:

93 days

Frequency of treatment:

6 h/d, 5 d/w

Dose / conc.:

8 ppm (analytical)

Remarks:

(corresponding to 24 mg/m3)

Dose / conc.:

16 ppm (analytical)

Remarks:

(corresponding to 49 mg/m3)

Dose / conc.:

32 ppm (analytical)

Remarks:

(corresponding to 97 mg/m3)

Dose / conc.:

62 ppm (analytical)

Remarks:

(corresponding to 188 mg/m3)

Dose / conc.:

125 ppm (analytical)

Remarks:

(corresponding to 379 mg/m3)

No. of animals per sex per dose:

10

Control animals:

yes

Details on study design:

- Dose selection rationale: Because exposure to 250 or 500 ppm diethylamine for 16 days caused significantly decreased body weights in rats, a high concentration of 125 ppm was selected for both sexes in the 3-month study. Although nasal lesions were present in rats exposed to 125 ppm for 16 days, these lesions were generally mild and were not likely to compromise the 3-month study. Diethylamine exposure concentrations of 0, 8, 16, 32, 62, and 125 ppm were selected for both sexes of rats in the 3-month study.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: twice daily

BODY WEIGHT: Yes
- Time schedule for examinations: days 0, 7 and weekly afterwards

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: Yes
- Time schedule for collection of blood: days 0, 23 and 93
- Anaesthetic used for blood collection: Yes
- How many animals: all
- Parameters examined: Erythrocyte count, Mean corpuscular volume, Hemoglobin, Packed cell volume, Mean corpuscular hemoglobin, Mean corpuscular hemoglobin concentration, Erythrocyte morphologic assessment, Leukocyte count, Leukocyte differential, Reticulocyte count, Platelet count and morphologic assessment

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: days 0, 23 and 93
- How many animals: all
- Parameters examined: Sorbitol dehydrogenase (SDH), Alkaline Phosphatase (ALP), Creatine Kinase (CK), Creatinine, Total Protein, Albumin, Urea Nitrogen (BUN), Total Bile Acids, Alanine Aminotransferase (ALT), Glucose

URINALYSIS: No data

NEUROBEHAVIOURAL EXAMINATION: No data

OTHER: Organs weighed were heart, right kidney, liver, lung, right testis, and thymus

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, a complete necropsy was performed on all treated and control animals that either died or were sacrificed

HISTOPATHOLOGY: Complete histopathology was performed on 0 and 125 ppm core study rats. In addition to gross lesions and tissue masses, the following tissues were examined to a no-effect level: adrenal gland, bone with marrow, brain, clitoral gland, esophagus, eyes, Harderian gland, heart, large intestine (cecum, colon, rectum), small intestine (duodenum, jejunum, ileum), kidney, larynx, liver, lungs, lymph nodes (bronchial, mandibular, mediastinal, and mesenteric), mammary gland, nose, ovary, pancreas, parathyroid gland, pituitary gland, preputial gland, prostate gland, salivary gland, skin, spleen, stomach (forestomach and glandular), testis with epididymis and seminal vesicle, thymus, thyroid gland, trachea, urinary bladder, and uterus.

Details on results:

CLINICAL SIGNS AND MORTALITY
All rats survived to the end of the study. The only clinical finding was a single occurrence of a torso lateral ulcer/abscess in a 125 ppm male.

BODY WEIGHT AND WEIGHT GAIN
Final mean body weights and body weight gains of all exposed groups were similar to those of the chamber control groups.

HAEMATOLOGY
There were no exposure-related changes in hematology endpoints.

CLINICAL CHEMISTRY
There were no exposure-related changes in clinical chemistry endpoints.

ORGAN WEIGHTS
The relative kidney weights of all groups of exposed females were increased and were significantly greater than those of the chamber controls, except in the 32 ppm group. The relative liver weight of 125 ppm males was significantly increased.

HISTOPATHOLOGY: NON-NEOPLASTIC
Exposure-related histopathology findings in rats were limited to the nose and were seen primarily in rats exposed to 62 or 125 ppm. These lesions included turbinate necrosis, suppurative inflammation, respiratory epithelial hyperplasia, squamous metaplasia of the respiratory epithelium, and olfactory epithelial atrophy.

There were no inflammatory changes of the eye as had been observed in the 2-week study at higher concentrations.

OTHER FINDINGS
There was a dose-related decrease seen in the motility of sperm from male rats with the values of those exposed to 32, 62, or 125 ppm diethylamine being significantly lower (5-26%) than those of the chamber controls; no significant differences were observed in the estrous cyclicity of female rats administered 32, 62, or 125 ppm diethylamine when compared to the chamber controls.

Key result

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

16 ppm

Based on:

test mat.

Remarks:

equivalent to 49 mg/m3 and 0.049 mg/L air

Sex:

male

Basis for effect level:

other: sperm motility

Key result

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

125 ppm

Based on:

test mat.

Remarks:

equivalent to 379 mg/m3 and 0.379 mg/L air

Sex:

female

Basis for effect level:

other: no adverse systemic effcets observed up to the highest dose tested

Key result

Dose descriptor:

NOAEC

Remarks:

local

Effect level:

16 ppm

Based on:

test mat.

Remarks:

equivalent to 49 mg/m3 and 0.049 mg/L air

Sex:

male/female

Basis for effect level:

histopathology: non-neoplastic

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

32 ppm

System:

respiratory system: upper respiratory tract

Organ:

nasal cavity

Treatment related:

yes

Dose response relationship:

yes

Conclusions:

DEA was studied in a subchronic study in rats using the NTP standard protocol. From the data a NOAEC for systemic and local toxicity of 16 ppm (corresponding to 49 mg/m3) was established.

Executive summary:

Diethylamine (DEA) provides a suitable surrogate for diethylamine hydrochloride. DEA was studied in a subchronic study in rats using the NTP standard protocol. The report is publicly avaialable on the NTP website (TR 566).

In the study groups of 10 male and 10 female rats were exposed to diethylamine vapor at concentrations of 0, 8, 16, 32, 62, or 125 ppm (corresponding to 24, 49, 97, 188 and 379 mg/m³, respectively), 6 hours plus T90 (12 minutes) per day, 5 days per week for 14 weeks. All rats survived to the end of the study. Mean body weights of all exposed groups were similar to those of the chamber control groups. There were significant exposure concentration-related decreases in sperm motility in 32, 62, and 125 ppm males; there were no significant differences in the lengths of estrous cycles between chamber control and exposed groups of females. Exposure-related nasal lesions were seen primarily in rats exposed to 62 or 125 ppm, but occurred already at 32 ppm, although not reaching the level of statistical significance. These lesions included turbinate necrosis, suppurative inflammation, respiratory epithelial hyper-plasia, squamous metaplasia of the respiratory epithelium, and olfactory epithelial atrophy.

From the data a NOAEC for systemic and local toxicity of 16 ppm (corresponding to 49 mg/m³) could be established.

Reference 2

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented report which meets basic scientific principles. Study performed according to standard NTP protocols.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

GLP compliance:

yes

Limit test:

no

Species:

mouse

Strain:

CB6F1

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Taconic Farms, Inc. (Germantown, NY)
- Age at study initiation: approximately 6 weeks
- Weight at study initiation: males: 23.3 g (mean), female: 19.8 g (mean)
- Housing: individually in stainless steel wire bottom (Lab Products, Inc., Seaford, DE), changed weekly and rotated daily
- Diet: NTP-2000 irradiated wafers (Zeigler Brothers, Inc., Gardners, PA), available ad libitum, except during exposure periods
- Water: Tap water (Richland municipal supply) via automatic watering system (Edstrom Industries, Waterford, WI), available ad libitum
- Acclimation period: 12 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±3 °C (72°±3 °F)
- Humidity (%): 50% ± 15%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged

Details on inhalation exposure:

Diethylamine was pumped onto glass beads in a heated glass column where it was vaporized. Heated nitrogen flowed through the column and carried the vapor into a short vapor distribution manifold. Concentration in the manifold was determined by the chemical pump rate and nitrogen flow rate. The pressure in the distribution manifold was kept fixed to ensure constant flow through the manifold and into all chambers as the flow of vapor to each chamber was adjusted.
Individual Teflon® delivery lines carried the vapor from the manifold to three-way exposure valves at the chamber inlets. The exposure valves diverted vapor delivery to the exposure chamber exhaust until the generation system was stable and exposures were ready to proceed. A metering valve with a flow indicator at the manifold controlled the flow rate to each chamber. To initiate exposure, the chamber exposure valves were rotated to allow the vapor to flow to each exposure chamber inlet duct where it was further diluted with HEPA®-filtered, conditioned air to achieve the desired exposure concentration.
The study laboratory designed the inhalation exposure chamber (Harford Systems Division of Lab Products, Inc., Aberdeen, MD) so that uniform vapor concen-trations could be maintained throughout the chamber with the catch pans in place. The total active mixing volume of each chamber was 1.7 m3. A small particle detector was used with and without animals in the exposure chambers to ensure that diethylamine vapor, and not aerosol, was produced. No particle counts above the minimum resolvable level (approximately 200 particles/cm3) were detected.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The on-line gas chromatograph was checked throughout the day for instrument drift against an on-line standard of diethylamine in nitrogen supplied by a standard generator. The on-line gas chromatograph was calibrated by a comparison of chamber concentration data to data from grade samples that were collected with acrylic ester adsorbent gas sampling tubes, extracted with methylene chloride containing triethylamine as an internal standard, and analyzed using an off-line gas chromatograph. Known values of chamber atmosphere were sampled at a constant flow rate ensured by a calibrated orifice. The off-line gas chromatograph was calibrated with gravimetrically prepared standards of diethylamine and the internal standard (triethylamine) in methylene chloride.

Duration of treatment / exposure:

93 days

Frequency of treatment:

6 h/d, 5 d/w

Dose / conc.:

8 ppm (analytical)

Remarks:

(corresponding to 24 mg/m3)

Dose / conc.:

16 ppm (analytical)

Remarks:

(corresponding to 49 mg/m3)

Dose / conc.:

32 ppm (analytical)

Remarks:

(corresponding to 97 mg/m3)

Dose / conc.:

62 ppm (analytical)

Remarks:

(corresponding to 188 mg/m3)

Dose / conc.:

125 ppm (analytical)

Remarks:

(corresponding to 379 mg/m3)

No. of animals per sex per dose:

10

Control animals:

yes

Details on study design:

- Dose selection rationale:
Because exposure to 250 and 500 ppm diethylamine for 17 days caused mortality in mice and body weight losses exceeding 18%, a high concentration of 125 ppm was selected for both sexes of mice in the 3-month study. Although nasal lesions were present in mice exposed to 125 ppm for 17 days, these lesions were generally mild and were not likely to compromise the 3-month study. Diethylamine exposure concentrations of 0, 8, 16, 32, 62 and 125 ppm were selected for both sexes of mice in the 3-month study

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: twice daily

BODY WEIGHT: Yes
- Time schedule for examinations: days 0, 7 and weekly afterwards

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: Yes
- Time schedule for collection of blood: days 0, 23 and 93
- Anaesthetic used for blood collection: Yes
- How many animals: all
- Parameters examined: Erythrocyte count, Mean corpuscular volume, Hemoglobin, Packed cell volume, Mean corpuscular hemoglobin, Mean corpuscular hemoglobin concentration, Erythrocyte morphologic assessment, Leukocyte count, Leukocyte differential, Reticulocyte count, Platelet count and morphologic assessment

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: days 0, 23 and 93
- How many animals: all
- Parameters examined: Sorbitol dehydrogenase (SDH), Alkaline Phosphatase (ALP), Creatine Kinase (CK), Creatinine, Total Protein, Albumin, Urea Nitrogen (BUN), Total Bile Acids, Alanine Aminotransferase (ALT), Glucose

URINALYSIS: No data

NEUROBEHAVIOURAL EXAMINATION: No data

OTHER: Organs weighed were heart, right kidney, liver, lung, right testis, and thymus

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, a complete necropsy was performed on all treated and control animals that either die or are sacrificed

HISTOPATHOLOGY: Complete histopathology was performed on 0 and 125 ppm core study rats. In addition to gross lesions and tissue masses, the following tissues were examined to a no-effect level: adrenal gland, bone with marrow, brain, clitoral gland, esophagus, eyes, Harderian gland, heart, large intestine (cecum, colon, rectum), small intestine (duodenum, jejunum, ileum), kidney, larynx, liver, lungs, lymph nodes (bronchial, mandibular, mediastinal, and mesenteric), mammary gland, nose, ovary, pancreas, parathyroid gland, pituitary gland, preputial gland, prostate gland, salivary gland, skin, spleen, stomach (forestomach and glandular), testis with epididymis and seminal vesicle, thymus, thyroid gland, trachea, urinary bladder, and uterus.

Statistics:

Standard statistical methods have been applied for data processing.

Key result

Dose descriptor:

NOAEC

Remarks:

local

Effect level:

16 ppm

Based on:

test mat.

Remarks:

equivalent to 49 mg/m3

Sex:

male/female

Basis for effect level:

histopathology: non-neoplastic

Key result

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

16 ppm

Based on:

test mat.

Remarks:

equivalent to 49 mg/m3 and 0.049 mg/L ait

Sex:

male

Basis for effect level:

other: sperm motility

Key result

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

32 ppm

Based on:

test mat.

Remarks:

equivalent to 97 mg/m3 and 0.097 mg/L air

Sex:

female

Basis for effect level:

other: changes in estrous cycling

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

32 ppm

System:

respiratory system: upper respiratory tract

Organ:

nasal cavity

Treatment related:

yes

Dose response relationship:

yes

Conclusions:

DEA was studied in a subchronic study to mice using the NTP standard protocol. From the data a NOAEC for systemic and local toxicity of 16 ppm could be established.

Executive summary:

Diethylamine (DEA) provides a suitable surrogate for diethylamine hydrochloride.

DEA was studied in a subchronic study in mice using the NTP standard protocol. The report is publicly avaialable on the NTP website (TR 566).

In the studies groups of 10 male and 10 female mice were exposed to diethylamine vapor at concentrations of 0, 8, 16, 32, 62, or 125 ppm (corresponding to 24, 49, 97, 1882 and 379 mg/m³, respectively)

, 6 hours plus T90 (12 minutes) per day, 5 days per week for 14 weeks. All mice survived to the end of the study. The mean body weights of 125 ppm males and females were significantly less than those of the chamber controls. There were significant exposure concentration-related decreases in sperm motility in males exposed to 32, 62, or 125 ppm; the estrous cycle of 125 ppm females was significantly longer than that of the chamber controls but only by half a day. Histopathologic changes were noted primarily in the nasal cavity and involved both the respiratory and olfactory epithelium of males and females principally in the 62 or 125 ppm groups. These lesions included suppurative inflammation, squamous metaplasia of the respiratory epithelium, olfactory epithelial atrophy, and necrosis of the turbinates.

From the data a local and systemic NOAEC of 16 ppm (corresponding to 49 mg/m³) could be established.

Reference 3

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Rationale for reliability incl. deficiencies:

other: Scientific study according to NTP standard protocol that fully meets documentation requirements.

Justification for type of information:

refer to analogue justification provided in IUCLID section 13

Reason / purpose for cross-reference:

read-across source

Control animals:

yes

Key result

Dose descriptor:

NOAEC

Remarks:

local

Effect level:

16 ppm

Based on:

test mat.

Remarks:

corresponding to 49 mg/m3 and 0.049 mg/L air

Sex:

male/female

Basis for effect level:

histopathology: non-neoplastic

Key result

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

16 ppm

Based on:

test mat.

Remarks:

equivalent to 49 mg/m3 and 0.049 mg/L air

Sex:

male

Basis for effect level:

other: sperm motility

Key result

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

32 ppm

Based on:

test mat.

Remarks:

equivalent to 97 mg/m3 and 0.097 mg/L air

Sex:

female

Basis for effect level:

other: changes in estrous cycling

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

32 ppm

System:

respiratory system: upper respiratory tract

Organ:

nasal cavity

Treatment related:

yes

Dose response relationship:

yes

Conclusions:

DEA was studied in a subchronic study in mice using the NTP standard protocol. From the data a NOAEC for systemic and local toxicity of 16 ppm could be established.

Executive summary:

Diethylamine (DEA) provides a suitable surrogate for diethylamine hydrochloride. DEA was studied in a subchronic study in mice using the NTP standard protocol. The report is publicly avaialable on the NTP website (TR 566).

In the studies groups of 10 male and 10 female mice were exposed to diethylamine vapor at concentrations of 0, 8, 16, 32, 62, or 125 ppm

(corresponding to 24, 49, 97, 188 and 379 mg/m³, respectively)

, 6 hours plus T90 (12 minutes) per day, 5 days per week for 14 weeks. All mice survived to the end of the study. The mean body weights of 125 ppm males and females were significantly less than those of the chamber controls. There were significant exposure concentration-related decreases in sperm motility in males exposed to 32, 62, or 125 ppm; the estrous cycle of 125 ppm females was significantly longer than that of the chamber controls but only by half a day. Histopathologic changes were noted primarily in the nasal cavity and involved both the respiratory and olfactory epithelium of males and females in the 32, 62 or 125 ppm groups. These lesions included suppurative inflammation, squamous metaplasia of the respiratory epithelium, olfactory epithelial atrophy, and necrosis of the turbinates.

From the data a local and systemic NOAEC of 16 ppm (corresponding to 49 mg/m³) could be established.

Reference 4

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Study period:

2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Scientific study according to NTP standard protocol that fully meets documentation requirements.

Justification for type of information:

refer to analogue justification provided in IUCLID section 13

Reason / purpose for cross-reference:

read-across source

Details on results:

CLINICAL SIGNS AND MORTALITY
All rats survived to the end of the study. The only clinical finding was a single occurrence of a torso lateral ulcer/abscess in a 125 ppm male.

BODY WEIGHT AND WEIGHT GAIN
Final mean body weights and body weight gains of all exposed groups were similar to those of the chamber control groups.

HAEMATOLOGY
There were no exposure-related changes in hematology endpoints.

CLINICAL CHEMISTRY
There were no exposure-related changes in clinical chemistry endpoints.

ORGAN WEIGHTS
The relative kidney weights of all groups of exposed females were increased and were significantly greater than those of the chamber controls, except in the 32 ppm group. The relative liver weight of 125 ppm males was significantly increased.

HISTOPATHOLOGY: NON-NEOPLASTIC
Exposure-related histopathology findings in rats were limited to the nose and were seen primarily in rats exposed to 62 or 125 ppm. These lesions included turbinate necrosis, suppurative inflammation, respiratory epithelial hyperplasia, squamous metaplasia of the respiratory epithelium, and olfactory epithelial atrophy.

There were no inflammatory changes of the eye as had been observed in the 2-week study at higher concentrations.

OTHER FINDINGS
There was a dose-related decrease seen in the motility of sperm from male rats with the values of those exposed to 32, 62, or 125 ppm diethylamine being significantly lower (5-26%) than those of the chamber controls; no significant differences were observed in the estrous cyclicity of female rats administered 32, 62, or 125 ppm diethylamine when compared to the chamber controls.

Key result

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

16 ppm

Based on:

test mat.

Remarks:

equivalent to 49 mg/m3 and 0.049 mg/L air

Sex:

male

Basis for effect level:

other: sperm motility

Key result

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

125 ppm

Based on:

test mat.

Remarks:

equivalent to 379 mg/m3 and 0.379 mg/L air

Sex:

female

Basis for effect level:

other: no adverse systemic effects observed up to the highest dose tested

Key result

Dose descriptor:

NOAEC

Remarks:

local

Effect level:

16 ppm

Based on:

test mat.

Remarks:

equivalent to 49 mg/m3 and 0.049 mg/L air

Sex:

male/female

Basis for effect level:

histopathology: non-neoplastic

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

32 ppm

System:

respiratory system: upper respiratory tract

Organ:

nasal cavity

Treatment related:

yes

Dose response relationship:

yes

Conclusions:

DEA was studied in a subchronic study in rats using the NTP standard protocol. From the data a NOAEC for systemic and local toxicity of 16 ppm was established.

Executive summary:

Diethylamine (DEA) provides a suitable surrogate for diethylamine hydrochloride. DEA was studied in a subchronic study in rats using the NTP standard protocol. The report is publicly avaialable on the NTP website (TR 566).

In the study groups of 10 male and 10 female rats were exposed to diethylamine vapor at concentrations of 0, 8, 16, 32, 62, or 125 ppm (corresponding to 24, 49, 97, 188 and 379 mg/m³, respectively), 6 hours plus T90 (12 minutes) per day, 5 days per week for 14 weeks. All rats survived to the end of the study. Mean body weights of all exposed groups were similar to those of the chamber control groups. There were significant exposure concentration-related decreases in sperm motility in 32, 62, and 125 ppm males; there were no significant differences in the lengths of estrous cycles between chamber control and exposed groups of females. Exposure-related nasal lesions were seen primarily in rats exposed to 62 or 125 ppm, but occurred already at 32 ppm, although not reaching the level of statistical significance. These lesions included turbinate necrosis, suppurative inflammation, respiratory epithelial hyper-plasia, squamous metaplasia of the respiratory epithelium, and olfactory epithelial atrophy.

From the data a NOAEC for systemic and local toxicity of 16 ppm (corresponding to 49 mg/m³) could be established.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEC

49 mg/m³

Study duration:

subchronic

Species:

other: rat and mouse

Quality of whole database:

The available information comprises adequate and reliable (Klimisch score 2) and consistent studies, and is thus sufficient to fulfil the standard information requirements set out in Annex VIII-IX, 8.6, of Regulation (EC) No 1907/2006.

System:

other: males and female reproductive system

Organ:

other: sperm motility and estrous length

Repeated dose toxicity: inhalation - local effects

Link to relevant study records

Reference

Reference 1

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented report which meets basic scientific principles. Study performed according to standard NTP protocols.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

GLP compliance:

yes

Limit test:

no

Species:

mouse

Strain:

CB6F1

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Taconic Farms, Inc. (Germantown, NY)
- Age at study initiation: approximately 6 weeks
- Weight at study initiation: males: 23.3 g (mean), female: 19.8 g (mean)
- Housing: individually in stainless steel wire bottom (Lab Products, Inc., Seaford, DE), changed weekly and rotated daily
- Diet: NTP-2000 irradiated wafers (Zeigler Brothers, Inc., Gardners, PA), available ad libitum, except during exposure periods
- Water: Tap water (Richland municipal supply) via automatic watering system (Edstrom Industries, Waterford, WI), available ad libitum
- Acclimation period: 12 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±3 °C (72°±3 °F)
- Humidity (%): 50% ± 15%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged

Details on inhalation exposure:

Diethylamine was pumped onto glass beads in a heated glass column where it was vaporized. Heated nitrogen flowed through the column and carried the vapor into a short vapor distribution manifold. Concentration in the manifold was determined by the chemical pump rate and nitrogen flow rate. The pressure in the distribution manifold was kept fixed to ensure constant flow through the manifold and into all chambers as the flow of vapor to each chamber was adjusted.
Individual Teflon® delivery lines carried the vapor from the manifold to three-way exposure valves at the chamber inlets. The exposure valves diverted vapor delivery to the exposure chamber exhaust until the generation system was stable and exposures were ready to proceed. A metering valve with a flow indicator at the manifold controlled the flow rate to each chamber. To initiate exposure, the chamber exposure valves were rotated to allow the vapor to flow to each exposure chamber inlet duct where it was further diluted with HEPA®-filtered, conditioned air to achieve the desired exposure concentration.
The study laboratory designed the inhalation exposure chamber (Harford Systems Division of Lab Products, Inc., Aberdeen, MD) so that uniform vapor concen-trations could be maintained throughout the chamber with the catch pans in place. The total active mixing volume of each chamber was 1.7 m3. A small particle detector was used with and without animals in the exposure chambers to ensure that diethylamine vapor, and not aerosol, was produced. No particle counts above the minimum resolvable level (approximately 200 particles/cm3) were detected.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The on-line gas chromatograph was checked throughout the day for instrument drift against an on-line standard of diethylamine in nitrogen supplied by a standard generator. The on-line gas chromatograph was calibrated by a comparison of chamber concentration data to data from grade samples that were collected with acrylic ester adsorbent gas sampling tubes, extracted with methylene chloride containing triethylamine as an internal standard, and analyzed using an off-line gas chromatograph. Known values of chamber atmosphere were sampled at a constant flow rate ensured by a calibrated orifice. The off-line gas chromatograph was calibrated with gravimetrically prepared standards of diethylamine and the internal standard (triethylamine) in methylene chloride.

Duration of treatment / exposure:

93 days

Frequency of treatment:

6 h/d, 5 d/w

Dose / conc.:

8 ppm (analytical)

Remarks:

(corresponding to 24 mg/m3)

Dose / conc.:

16 ppm (analytical)

Remarks:

(corresponding to 49 mg/m3)

Dose / conc.:

32 ppm (analytical)

Remarks:

(corresponding to 97 mg/m3)

Dose / conc.:

62 ppm (analytical)

Remarks:

(corresponding to 188 mg/m3)

Dose / conc.:

125 ppm (analytical)

Remarks:

(corresponding to 379 mg/m3)

No. of animals per sex per dose:

10

Control animals:

yes

Details on study design:

- Dose selection rationale:
Because exposure to 250 and 500 ppm diethylamine for 17 days caused mortality in mice and body weight losses exceeding 18%, a high concentration of 125 ppm was selected for both sexes of mice in the 3-month study. Although nasal lesions were present in mice exposed to 125 ppm for 17 days, these lesions were generally mild and were not likely to compromise the 3-month study. Diethylamine exposure concentrations of 0, 8, 16, 32, 62 and 125 ppm were selected for both sexes of mice in the 3-month study

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: twice daily

BODY WEIGHT: Yes
- Time schedule for examinations: days 0, 7 and weekly afterwards

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: Yes
- Time schedule for collection of blood: days 0, 23 and 93
- Anaesthetic used for blood collection: Yes
- How many animals: all
- Parameters examined: Erythrocyte count, Mean corpuscular volume, Hemoglobin, Packed cell volume, Mean corpuscular hemoglobin, Mean corpuscular hemoglobin concentration, Erythrocyte morphologic assessment, Leukocyte count, Leukocyte differential, Reticulocyte count, Platelet count and morphologic assessment

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: days 0, 23 and 93
- How many animals: all
- Parameters examined: Sorbitol dehydrogenase (SDH), Alkaline Phosphatase (ALP), Creatine Kinase (CK), Creatinine, Total Protein, Albumin, Urea Nitrogen (BUN), Total Bile Acids, Alanine Aminotransferase (ALT), Glucose

URINALYSIS: No data

NEUROBEHAVIOURAL EXAMINATION: No data

OTHER: Organs weighed were heart, right kidney, liver, lung, right testis, and thymus

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, a complete necropsy was performed on all treated and control animals that either die or are sacrificed

HISTOPATHOLOGY: Complete histopathology was performed on 0 and 125 ppm core study rats. In addition to gross lesions and tissue masses, the following tissues were examined to a no-effect level: adrenal gland, bone with marrow, brain, clitoral gland, esophagus, eyes, Harderian gland, heart, large intestine (cecum, colon, rectum), small intestine (duodenum, jejunum, ileum), kidney, larynx, liver, lungs, lymph nodes (bronchial, mandibular, mediastinal, and mesenteric), mammary gland, nose, ovary, pancreas, parathyroid gland, pituitary gland, preputial gland, prostate gland, salivary gland, skin, spleen, stomach (forestomach and glandular), testis with epididymis and seminal vesicle, thymus, thyroid gland, trachea, urinary bladder, and uterus.

Statistics:

Standard statistical methods have been applied for data processing.

Key result

Dose descriptor:

NOAEC

Remarks:

local

Effect level:

16 ppm

Based on:

test mat.

Remarks:

equivalent to 49 mg/m3

Sex:

male/female

Basis for effect level:

histopathology: non-neoplastic

Key result

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

16 ppm

Based on:

test mat.

Remarks:

equivalent to 49 mg/m3 and 0.049 mg/L ait

Sex:

male

Basis for effect level:

other: sperm motility

Key result

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

32 ppm

Based on:

test mat.

Remarks:

equivalent to 97 mg/m3 and 0.097 mg/L air

Sex:

female

Basis for effect level:

other: changes in estrous cycling

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

32 ppm

System:

respiratory system: upper respiratory tract

Organ:

nasal cavity

Treatment related:

yes

Dose response relationship:

yes

Conclusions:

DEA was studied in a subchronic study to mice using the NTP standard protocol. From the data a NOAEC for systemic and local toxicity of 16 ppm could be established.

Executive summary:

Diethylamine (DEA) provides a suitable surrogate for diethylamine hydrochloride.

DEA was studied in a subchronic study in mice using the NTP standard protocol. The report is publicly avaialable on the NTP website (TR 566).

In the studies groups of 10 male and 10 female mice were exposed to diethylamine vapor at concentrations of 0, 8, 16, 32, 62, or 125 ppm (corresponding to 24, 49, 97, 1882 and 379 mg/m³, respectively)

, 6 hours plus T90 (12 minutes) per day, 5 days per week for 14 weeks. All mice survived to the end of the study. The mean body weights of 125 ppm males and females were significantly less than those of the chamber controls. There were significant exposure concentration-related decreases in sperm motility in males exposed to 32, 62, or 125 ppm; the estrous cycle of 125 ppm females was significantly longer than that of the chamber controls but only by half a day. Histopathologic changes were noted primarily in the nasal cavity and involved both the respiratory and olfactory epithelium of males and females principally in the 62 or 125 ppm groups. These lesions included suppurative inflammation, squamous metaplasia of the respiratory epithelium, olfactory epithelial atrophy, and necrosis of the turbinates.

From the data a local and systemic NOAEC of 16 ppm (corresponding to 49 mg/m³) could be established.

Reference 2

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Scientific study according to NTP standard protocol that fully meets documentation requirements.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Taconic Farms, Inc. (Germantown, NY)
- Age at study initiation: approximately 6 weeks
- Weight at study initiation: males: 110 g (mean), female: 93 g (mean)
- Housing: individually in stainless steel wire bottom (Lab Products, Inc., Seaford, DE), changed weekly and rotated daily
- Diet: NTP-2000 irradiated wafers (Zeigler Brothers, Inc., Gardners, PA), available ad libitum, except during exposure periods
- Water: Tap water (Richland municipal supply) via automatic watering system (Edstrom Industries, Waterford, WI), available ad libitum
- Acclimation period: 12 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±3 °C (72°±3 °F)
- Humidity (%): 50% ± 15%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Remarks:

inhalation chamber

Vehicle:

other: unchanged

Details on inhalation exposure:

Diethylamine was pumped onto glass beads in a heated glass column where it was vaporized. Heated nitrogen flowed through the column and carried the vapor into a short vapor distribution manifold. Concentration in the manifold was determined by the chemical pump rate and nitrogen flow rate. The pressure in the distribution manifold was kept fixed to ensure constant flow through the manifold and into all chambers as the flow of vapor to each chamber was adjusted.
Individual Teflon® delivery lines carried the vapor from the manifold to three-way exposure valves at the chamber inlets. The exposure valves diverted vapor delivery to the exposure chamber exhaust until the generation system was stable and exposures were ready to proceed. A metering valve with a flow indicator at the manifold controlled the flow rate to each chamber. To initiate exposure, the chamber exposure valves were rotated to allow the vapor to flow to each exposure chamber inlet duct where it was further diluted with HEPA®-filtered, conditioned air to achieve the desired exposure concentration.
The study laboratory designed the inhalation exposure chamber (Harford Systems Division of Lab Products, Inc., Aberdeen, MD) so that uniform vapor concen-trations could be maintained throughout the chamber with the catch pans in place. The total active mixing volume of each chamber was 1.7 m3. A small particle detector was used with and without animals in the exposure chambers to ensure that diethylamine vapor, and not aerosol, was produced. No particle counts above the minimum resolvable level (approximately 200 particles/cm3) were detected.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The on-line gas chromatograph was checked throughout the day for instrument drift against an on-line standard of diethylamine in nitrogen supplied by a standard generator. The on-line gas chromatograph was calibrated by a comparison of chamber concentration data to data from grade samples that were collected with acrylic ester adsorbent gas sampling tubes, extracted with methylene chloride containing triethylamine as an internal standard, and analyzed using an off-line gas chromatograph. Known values of chamber atmosphere were sampled at a constant flow rate ensured by a calibrated orifice. The off-line gas chromatograph was calibrated with gravimetrically prepared standards of diethylamine and the internal standard (triethylamine) in methylene chloride.

Duration of treatment / exposure:

93 days

Frequency of treatment:

6 h/d, 5 d/w

Dose / conc.:

8 ppm (analytical)

Remarks:

(corresponding to 24 mg/m3)

Dose / conc.:

16 ppm (analytical)

Remarks:

(corresponding to 49 mg/m3)

Dose / conc.:

32 ppm (analytical)

Remarks:

(corresponding to 97 mg/m3)

Dose / conc.:

62 ppm (analytical)

Remarks:

(corresponding to 188 mg/m3)

Dose / conc.:

125 ppm (analytical)

Remarks:

(corresponding to 379 mg/m3)

No. of animals per sex per dose:

10

Control animals:

yes

Details on study design:

- Dose selection rationale: Because exposure to 250 or 500 ppm diethylamine for 16 days caused significantly decreased body weights in rats, a high concentration of 125 ppm was selected for both sexes in the 3-month study. Although nasal lesions were present in rats exposed to 125 ppm for 16 days, these lesions were generally mild and were not likely to compromise the 3-month study. Diethylamine exposure concentrations of 0, 8, 16, 32, 62, and 125 ppm were selected for both sexes of rats in the 3-month study.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: twice daily

BODY WEIGHT: Yes
- Time schedule for examinations: days 0, 7 and weekly afterwards

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: Yes
- Time schedule for collection of blood: days 0, 23 and 93
- Anaesthetic used for blood collection: Yes
- How many animals: all
- Parameters examined: Erythrocyte count, Mean corpuscular volume, Hemoglobin, Packed cell volume, Mean corpuscular hemoglobin, Mean corpuscular hemoglobin concentration, Erythrocyte morphologic assessment, Leukocyte count, Leukocyte differential, Reticulocyte count, Platelet count and morphologic assessment

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: days 0, 23 and 93
- How many animals: all
- Parameters examined: Sorbitol dehydrogenase (SDH), Alkaline Phosphatase (ALP), Creatine Kinase (CK), Creatinine, Total Protein, Albumin, Urea Nitrogen (BUN), Total Bile Acids, Alanine Aminotransferase (ALT), Glucose

URINALYSIS: No data

NEUROBEHAVIOURAL EXAMINATION: No data

OTHER: Organs weighed were heart, right kidney, liver, lung, right testis, and thymus

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, a complete necropsy was performed on all treated and control animals that either died or were sacrificed

HISTOPATHOLOGY: Complete histopathology was performed on 0 and 125 ppm core study rats. In addition to gross lesions and tissue masses, the following tissues were examined to a no-effect level: adrenal gland, bone with marrow, brain, clitoral gland, esophagus, eyes, Harderian gland, heart, large intestine (cecum, colon, rectum), small intestine (duodenum, jejunum, ileum), kidney, larynx, liver, lungs, lymph nodes (bronchial, mandibular, mediastinal, and mesenteric), mammary gland, nose, ovary, pancreas, parathyroid gland, pituitary gland, preputial gland, prostate gland, salivary gland, skin, spleen, stomach (forestomach and glandular), testis with epididymis and seminal vesicle, thymus, thyroid gland, trachea, urinary bladder, and uterus.

Details on results:

CLINICAL SIGNS AND MORTALITY
All rats survived to the end of the study. The only clinical finding was a single occurrence of a torso lateral ulcer/abscess in a 125 ppm male.

BODY WEIGHT AND WEIGHT GAIN
Final mean body weights and body weight gains of all exposed groups were similar to those of the chamber control groups.

HAEMATOLOGY
There were no exposure-related changes in hematology endpoints.

CLINICAL CHEMISTRY
There were no exposure-related changes in clinical chemistry endpoints.

ORGAN WEIGHTS
The relative kidney weights of all groups of exposed females were increased and were significantly greater than those of the chamber controls, except in the 32 ppm group. The relative liver weight of 125 ppm males was significantly increased.

HISTOPATHOLOGY: NON-NEOPLASTIC
Exposure-related histopathology findings in rats were limited to the nose and were seen primarily in rats exposed to 62 or 125 ppm. These lesions included turbinate necrosis, suppurative inflammation, respiratory epithelial hyperplasia, squamous metaplasia of the respiratory epithelium, and olfactory epithelial atrophy.

There were no inflammatory changes of the eye as had been observed in the 2-week study at higher concentrations.

OTHER FINDINGS
There was a dose-related decrease seen in the motility of sperm from male rats with the values of those exposed to 32, 62, or 125 ppm diethylamine being significantly lower (5-26%) than those of the chamber controls; no significant differences were observed in the estrous cyclicity of female rats administered 32, 62, or 125 ppm diethylamine when compared to the chamber controls.

Key result

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

16 ppm

Based on:

test mat.

Remarks:

equivalent to 49 mg/m3 and 0.049 mg/L air

Sex:

male

Basis for effect level:

other: sperm motility

Key result

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

125 ppm

Based on:

test mat.

Remarks:

equivalent to 379 mg/m3 and 0.379 mg/L air

Sex:

female

Basis for effect level:

other: no adverse systemic effcets observed up to the highest dose tested

Key result

Dose descriptor:

NOAEC

Remarks:

local

Effect level:

16 ppm

Based on:

test mat.

Remarks:

equivalent to 49 mg/m3 and 0.049 mg/L air

Sex:

male/female

Basis for effect level:

histopathology: non-neoplastic

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

32 ppm

System:

respiratory system: upper respiratory tract

Organ:

nasal cavity

Treatment related:

yes

Dose response relationship:

yes

Conclusions:

DEA was studied in a subchronic study in rats using the NTP standard protocol. From the data a NOAEC for systemic and local toxicity of 16 ppm (corresponding to 49 mg/m3) was established.

Executive summary:

Diethylamine (DEA) provides a suitable surrogate for diethylamine hydrochloride. DEA was studied in a subchronic study in rats using the NTP standard protocol. The report is publicly avaialable on the NTP website (TR 566).

In the study groups of 10 male and 10 female rats were exposed to diethylamine vapor at concentrations of 0, 8, 16, 32, 62, or 125 ppm (corresponding to 24, 49, 97, 188 and 379 mg/m³, respectively), 6 hours plus T90 (12 minutes) per day, 5 days per week for 14 weeks. All rats survived to the end of the study. Mean body weights of all exposed groups were similar to those of the chamber control groups. There were significant exposure concentration-related decreases in sperm motility in 32, 62, and 125 ppm males; there were no significant differences in the lengths of estrous cycles between chamber control and exposed groups of females. Exposure-related nasal lesions were seen primarily in rats exposed to 62 or 125 ppm, but occurred already at 32 ppm, although not reaching the level of statistical significance. These lesions included turbinate necrosis, suppurative inflammation, respiratory epithelial hyper-plasia, squamous metaplasia of the respiratory epithelium, and olfactory epithelial atrophy.

From the data a NOAEC for systemic and local toxicity of 16 ppm (corresponding to 49 mg/m³) could be established.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEC

49 mg/m³

Study duration:

subchronic

Species:

other: rat and mouse

Quality of whole database:

The available information comprises adequate and reliable (Klimisch score 2) and consistent studies, and is thus sufficient to fulfil the standard information requirements set out in Annex VIII-IX, 8.6, of Regulation (EC) No 1907/2006.

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

Justification for read-across

There are no data available on repeated dose toxicity of diethylammonium chloride (CAS 660-68-4). Thus, read-across from the appropriate structural analogue substances (diethylamine, CAS 109-89-7 and trimethylamine, CAS 75-50-3) is conducted in accordance with Regulation (EC) No 1907/2006, Annex XI, 1.5. in order to fulfil the standard information requirements defined in Regulation (EC) No 1907/2006, Annex VIII, 8.6. Common functional groups and structural similarities combined with similar toxicokinetic properties of the source and target substance are the basis of read-across. A detailed justification for the analogue read-across approach is provided in the technical dossier (see IUCLID Section 13).

No dermal repeated dose toxicity studies are available.

Oral

Reliable data is available for the source substance trimethylamine (CAS 75-50-3). Trimethylamine was tested in a combined repeated dose oral toxicity study with the reproduction/developmental toxicity screening study according to OECD Guideline 422 (Takashima et al., 2003). 13 Sprague Dawley rats per sex and dose were treated via gavage with the test substance at doses of 8, 40 and 200 mg/kg bw/day, respectively. The control group received the vehicle water. Males were treated for 42 days. Females were treated for 2 weeks prior to breeding, continuing through breeding (2 weeks), gestation (3 weeks), lactation (4 days), and until the day of necropsy. Clinical observations, food consumption, body weights, hematology, clinical chemistry, urinalysis, organ weights and gross examination at necropsy, microscopic examination of various organs and tissues were used for detecting the effects of treatment. At 200 mg/kg bw/day, one male died on day 25 and on day 42, respectively. One high-dose female died on pregnancy day 22 (administration day 38). Clinical signs such as abnormal breathing noise and salivation were observed in the surviving animals and the animals of the high-dose group that died, respectively. In addition, emaciation and dyspnea were noted in the high-dose males that died. Based on the results of this study, the NOAEL systemic was derived to be 40 mg/kg bw/day.

Inhalation

90-days rat

A reliable inhalation repeated dose toxicity study (90-day) conducted with diethylamine (CAS 109-89-7) is available and was performed equivalent or similar to OECD 413 (reference 7.5.2-1). Groups of 10 male and 10 female Fisher 344 rats were exposed to diethylamine vapor at concentrations of 0, 8, 16, 32, 62, or 125 ppm (corresponding to 24, 49, 97, 188 and 379 mg/m³, respectively), 6 hours plus T90 (12 minutes) per day, 5 days per week for 14 weeks. All rats survived to the end of the study. Mean body weights of all exposed groups were similar to those of the chamber control groups. There were significant exposure concentration-related decreases in sperm motility in 32, 62, and 125 ppm males (no histopathological correlate was noted); there were no significant differences in the lengths of estrous cycles between chamber control and exposed groups of females. Exposure-related nasal lesions were seen primarily in rats exposed to 62 and 125 ppm, but occurred already at 32 ppm, although not reaching the level of statistical significance. These lesions included turbinate necrosis, suppurative inflammation, respiratory epithelial hyperplasia, squamous metaplasia of the respiratory epithelium, and olfactory epithelial atrophy indicative of severe irritation of the respiratory tract. Accordingly, the NOAEC for systemic and local effects was considered to be 16 ppm (corresponding to 49 mg/m³).

90-days mouse

A reliable inhalation repeated dose toxicity study (90-day) conducted with diethylamine (CAS 109-89-7) is available and was performed equivalent or similar to OECD 413 (NTP, 2011). Groups of 10 male and 10 female CB6F1 mice were exposed to diethylamine vapor at concentrations of 0, 8, 16, 32, 62, or 125 ppm (corresponding to 24, 49, 97, 188 and 379 mg/m³, respectively), 6 hours plus T90 (12 minutes) per day, 5 days per week for 14 weeks. All mice survived to the end of the study. The mean body weights of 125 ppm males and females were significantly less than those of the chamber controls. There were significant exposure concentration-related decreases in sperm motility in males exposed to 32, 62 and 125 ppm (no histopathological correlate was noted); the estrous cycle of 125 ppm females was significantly longer than that of the chamber controls but only by half a day (no histopathological correlate was noted). Histopathologic changes were noted in the nasal cavity and involved both the respiratory and olfactory epithelium of males and females at the 32, 62 or 125 ppm groups. These lesions included suppurative inflammation, squamous metaplasia of the respiratory epithelium, olfactory epithelial atrophy, and necrosis of the turbinates. Accordingly, the NOAEC for systemic and local effects was considered to be 16 ppm (corresponding to 49 mg/m³).

24 weeks rat

In this supporting study performed equivalent or similar to OECD 413, male and female Fischer 344 rats were exposed to 25 or 250 ppm diethylamine vapor (corresponding to 76 and 760 mg/m³), 6.5 h per day, 5 days per week, for 24 weeks in order to assess cardiac and other organ system toxicity (reference 7.5.2-3). Scheduled sacrifices were performed following 30, 60, and 120 days of exposure. During the first 2 weeks of exposure, the rats exposed at 250 ppm did not gain weight. After 2 weeks, however, the rate of weight gain of these rats was greater than that of controls. Nevertheless, mean body weights for both sexes of rats exposed at 250 ppm remained depressed compared to controls throughout the study. Sneezing, tearing, and reddened noses were seen in rats exposed at 250 ppm. Histopathologic examinations revealed lesions of the nasal mucosa of rats exposed at 250 ppm (rats exposed at 25 ppm were not evaluated). These lesions of the respiratory epithelium consisted of squamous metaplasia, suppurative rhinitis, and lymphoid hyperplasia. There were no pronounced treatment-related effects on organ weights, hematology, or clinical chemistry indices except for blood urea nitrogen which was evaluated in rats of both sexes exposed at 250 ppm for 24 weeks. In contrast to the high-dose animals, no treatment-related effects were observed in rats intermittently exposed at 25 ppm for up to 24 weeks. No evidence of cardiotoxicity was seen in rats exposed to either concentration for up to 24 weeks. Accordingly, the NOAEC in this study was considered to be 25 ppm (corresponding to 76 mg/m³).

In all repeated dose studies, the test substance diethylamine caused local irritating effects in the upper respiratory tract (respiratory and olfactory epithelium). These effects were already observed after single exposure in the acute inhalation toxicity study (reference 7.2.2-1). Thus the substance diethylamine was classified as specific target organ toxicant after single exposure Cat. 3 (STOT SE 3, respiratory irritation, H335).

Justification for classification or non-classification

According to Article 13 of Regulation (EC) No. 1907/2006 "General Requirements for Generation of Information on Intrinsic Properties of substances", information on intrinsic properties of substances may be generated by means other than tests e.g. from information from structurally related substances (grouping or read-across), provided that conditions set out in Annex XI are met. Annex XI, "General rules for adaptation of this standard testing regime set out in Annexes VII to X” states that “substances whose physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity may be considered as a group, or ‘category’ of substances. This avoids the need to test every substance for every endpoint". Since the analogue concept is applied to diethylammoinum chloride, data will be generated from information on reference source substance(s) to avoid unnecessary animal testing. Additionally, once the analogue read-across concept is applied, substances will be classified and labelled on this basis.

The available data on the source substance diethylamine on repeated dose toxicity following inhalation and the available data on the source substance trimethylamine on repeated dose toxicity following oral administration are conclusive but not sufficient to meet the criteria for classification according to Regulation (EC) 1272/2008. Applying the RA-A approach, similar results are expected for the target substance diethylammonium chloride.