Trimethylamine

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study; no data regarding GLP

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Materials and methods

Test guideline

Test guideline 1

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: OPPTS 870-3650

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Trimethylamine

EC Number:

200-875-0

EC Name:

Trimethylamine

Cas Number:

75-50-3

Molecular formula:

C3H9N

IUPAC Name:

N,N-dimethylmethanamine

Test material form:

liquid

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

- Age: 9 week old

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

no details given

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

no details given

Duration of treatment / exposure:

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:

Once daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

(in water)

Doses / concentrations 2

Dose / conc.:

8 mg/kg bw/day (nominal)

Remarks:

(in water)

Doses / concentrations 3

Dose / conc.:

40 mg/kg bw/day (nominal)

Remarks:

(in water)

Doses / concentrations 4

Dose / conc.:

200 mg/kg bw/day (nominal)

Remarks:

(in water)

No. of animals per sex per dose:

13/sex/dose group

Control animals:

yes, concurrent vehicle

Details on study design:

Post-exposure period: None

Examinations

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.
Haematology 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:

- Haematology 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.
ORGANS EXAMINED AT NECROPSY (MACROSCOPIC AND MICROSCOPIC):
- Macroscopic: organ weights: brain, heart, thymus, liver, kidneys, spleen, adrenals, testes and epididymides; pups were autopsied on day 4 and external and internal organs observed; with 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- brain, pituitary gland, spinal cord, digestive tract, liver, kidneys, adrenal, spleen, heart, thymus, thyroid gland, trachea, lung, bladder, mesenteric lymph nodes, lower jaw lymph nodes, sciatic nerves, thigh bone marrow, sperm and prostrate ventral lobes of all males and vagina, ovaries and uteri of all females; also testes, epididymides, ovaries and stomachs found to be abnormal during pathologic examinations were all examined histopathologically

Other examinations:

no data

Statistics:

Fisher's Exact Test- mating and conception rate,
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, haematology, clinical chemistry and organ weights

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Clinical signs prior to death
(200 mg/kg/day): Day 25 male, showed salivation, emaciation, abnormal breathing noise and dyspnea from administration day 19, and vulval periphery fur soil and loose passage were observed from the day before the death. Day 42 male, 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 was observed with salivation and abnormal breathing noise sporadically from administration day 11.
-Clinical signs in surviving animals:
200 mg/kg/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):

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/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/day. Females- No significant differences in body weight or body weight gains.
There was no effect of trimethylamine administration on body weights and food consumption of the females

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

There was no effect of trimethylamine administration on food consumption of the females

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Description (incidence and severity):

There was no effect of trimethylamine administration on haematological examination results in the males and females.

Clinical biochemistry findings:

not specified

Urinalysis findings:

no effects observed

Description (incidence and severity):

There was no effect of trimethylamine administration on urine examination in the males and females besides a significant increase in urea nitrogen at 40 mg/kg/day, which was not considered to be adverse.

Behaviour (functional findings):

not specified

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

There was no effect of trimethylamine administration on organ weights in the males and females.

Gross pathological findings:

not specified

Histopathological findings: neoplastic:

not specified

Details on results:

- 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)
- Clinical signs prior to death (200 mg/kg/day): Day 25 male, showed salivation, emaciation, abnormal breathing noise and dyspnea from administration day 19, and vulval periphery fur soil and loose passage were observed from the day before the death. Day 42 male, 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 was observed with salivation and abnormal breathing noise sporadically from administration day 11.
-Clinical signs in surviving animals: 200 mg/kg/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
-Body weights: Males- No significant differences in body weights at 200 mg/kg/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/day. Females- No significant differences in body weight or body weight gains.
There was no effect of trimethylamine administration on body weights and food consumption of the females and on organ weights, urine examination and haematological examination results in the males and females.

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

40 mg/kg bw/day (actual dose received)

Sex:

male/female

Basis for effect level:

other: general toxic changes 

2

Dose descriptor:

NOAEL

Effect level:

200 mg/kg bw/day (actual dose received)

Sex:

male/female

Basis for effect level:

other: reproductive/developmental toxic changes for both males and females and for delivered pups

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Daily oral administration of trimethylamine by gavage resulted in the death of two males and 1 female administered 200 mg/kg/day. Abnormal breathing noise, salivation immediately after the administration, ulcers and inflammatory changes in the stomach and intestinal tracts, squamous hyperplasia and oedema in submucosa were observed in both males and females in the 200 mg/kg/day group. An inhibition 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 haematological 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/day.

Executive summary:

Takashima et.al. performed in 2003 a subchronic repeated dose toxicity test according to OECD guideline 422. 13 male and female rats (Sprague-Dawley) each were exposed to a daily oral administration of trimethylamine by gavage. This resulted in the death of two males and 1 female administered 200 mg/kg/day. Abnormal breathing noise, salivation immediately after the administration, ulcers and inflammatory changes in the stomach and intestinal tracts, squamous hyperplasia and oedema in submucosa were observed in both males and females in the 200 mg/kg/day group. An inhibition 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 haematological examination results in the males and females. The slight increase in urea nitrogen observed at 40 mg/kg bw is not considered to be adverse. Therefore it was inferred that the general toxicological NOAEL (No Observed Adverse Effect Level) is 40 mg/kg/day.