Tetramethylammonium hydrogen phthalate

Endpoint summary

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September 1993 - March 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (U.K.) Limited, Hanston, Kent
- Age at study initiation: approximately five to six weeks old
- Weight at study initiation: males weighed 145g to 172g, females weighed 132g to 177g
- Fasting period before study: no
- Housing: in groups of five by sex in polypropylene gridfloor cages suspended over trays lined with absorbent paper
- Diet: free access to food, a pelleted diet (Rat and Mouse SQC Expanded Diet No. 1, Special Diets Services limited, Witham, Essex, U.K .)
- Water: free access to mains water
- Acclimation period: nine days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24
- Humidity (%): 42 - 81
- Air changes (per hr): at least 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 3 September 1993 To: 1 October 1993

Route of administration:

oral: gavage

Vehicle:

water

Remarks:

distilled

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
Formulations were prepared weekly and stored at 4°C in the dark. Treatment volume was 5 mL/kg bw.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples were taken of each test material formulation, and concentrations were determined spectrophotometrically.
Homogeneity was determined by visual examination.

Duration of treatment / exposure:

28 days

Frequency of treatment:

daily

Remarks:

Doses / Concentrations:
5, 15, 75 mg/kg bw/day
Basis:
actual ingested

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: based on the results of a range-finding study (rats, 3/sex/dose, were treated for 14 days to dose levels 0, 15, 40, 70, 100 mg/kg bw/day)

Positive control:

not required

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Immediately before dosing and one and five hours after dosing during the working week. Animals were observed immediately before dosing and one hour after dosing at weekends .

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: Individual bodyweights were recorded on Day 0 (the day before the start of treatment) and on Days 7, 14, 21 and 28.

FOOD CONSUMPTION: yes
- Food consumption was recorded for each cage group at weekly intervals throughout the study.

WATER CONSUMPTION: Yes
- Time schedule for examinations: Daily visual inspection of the water bottles during the first week of treatment revealed overt intergroup differences. Water intake was therefore measured and recorded for each cage group from Day 8 onwards.

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at the end of the study
- Anaesthetic used for blood collection: No data
- Animals fasted: No
- How many animals: all
- Parameters examined: Ht, Hb, RBC, WBC, differential leucocyte count, platelet count, MCH, MCV, MCHC, clotting time

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at the end of the study
- Animals fasted: No
- How many animals: all
- Parameters examined: blood urea, total protein, albumin, albumin/globulin ratio, sodium, potassium, chloride, calcium, inorganic phosphorus, creatinine, alkaline phosphatase (AP), alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), glucose, total bilirubin

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

OTHER: selected organs from animals that were killed at the end of
the study, were weighed before fixation: adrenals, brain, gonads, heart, kidneys, liver, pituitary, spleen

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes, according to guideline

Statistics:

Data were processed to give group mean values and standard deviations where appropriate.
Absolute and relative organ weights, haematological and blood chemical data were analysed by one way analysis of variance incorporating 'F-max ' test for homogeneity of variance. Data showing heterogeneous variances were analysed using Kruskal Wallis non-parametric analysis of variance and Mann Whitney U-Test.

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

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

effects observed, treatment-related

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not examined

Details on results:

CLINICAL SIGNS AND MORTALITY: No mortality observed. At the highest dose level clinical signs of toxicity, possibly associated with an adverse effect on the CNS, were seen on isolated occasions and included ptosis, lethargy and ataxia (shortlived and were no longer apparent by the following day). Increased salivation either before or immediately after dosing from Day 12 onwards. Associated findings of red/brown staining of the snout, red/brown staining around the mouth and fur wetting together with red/brown staining of the fur and red/brown staining around the ana-genital region. Abdominal distension was observed for two high dose males from Day 6 of treatment and for progressively more animals from Day 12 such that all high dose males had a distended abdomen throughout the second half of the treatment period. Several high dose animals of either sex occasionally appeared hunched during the second half of the treatment period or had red/brown staining around the eyes.

BODY WEIGHT AND WEIGHT GAIN: High dose males showed a lower bodyweight gain than controls over the treatment period, most notably during Week 1. High dose females also showed a lower bodyweight gain than controls during the first three weeks of treatment.

FOOD CONSUMPTION: The dietary intake of high dose males was lower than that of controls over the treatment period, particularly during Week 1 when food efficiency was also slightly reduced. High dose females showed a slightly lower dietary intake than controls during Week 1 only but food efficiency was unaffected by treatment in these animals.

WATER CONSUMPTION: Daily visual inspection of water bottles revealed overt intergroup differences during the first week of treatment and measurement of water consumption was therefore initiated on Day 8. A slight increase in water consumption was demonstrated for high dose animals of either sex in comparison with controls.

HAEMATOLOGY: High dose males showed a slight but statistically s ignificant increase in clotting time compared with controls; such findings are often associated with an adverse effect on the liver and, in this instance, a treatment related effect cannot be entirely ruled out.
Statistically significant reductions in haemoglobin concentration, haematocrit, platelet count, lymphocyte count and mean corpuscular haemoglobin concentration were confined to intermediate or low dose animals. These findings were not dose-related and were therefore considered not to be treatment-related.

CLINICAL CHEMISTRY: High dose animals showed statistically significant increase in plasma AP concentration and reduction in total plasma protein and albumin levels together with a rise in the albumin/globulin ratio. Statistically significant increases in ALAT and ASAT together with a reduction in plasma urea were confined to females (probably associated with the morphological hepatic changes detected histopathologically). High dose males showed a slight but statistically significant reduction in plasma sodium concentration whilst plasma calcium was slightly reduced in high dose females.
High dose animals of either sex showed a slight but statistically significant reduction in plasma creatinine concentration. None of the individual values were abnormally low and, in any case, a reduction in this parameter is unlikely to be associated with chemically-induced injury.

ORGAN WEIGHTS: High dose females showed a slight but statistically significant increase in relative liver weight compared with controls.
Statistically significant increases in female relative kidney weight and male relative testicular weight were detected at the high dose level. Most of the individual values were within the normally expected range for rats of the strain and age used in this study and, in the absence of any morphological renal or testicular changes, these findings were considered not to be toxicologically significant.

GROSS PATHOLOGY: All high dose males had a distended stomach at terminal kill. Multiple raised white foci were al so seen on the non-glandular gastric epithelium of one of these animals at necropsy.

HISTOPATHOLOGY: in high dose females hepatocyte basophilia and enlargement were observed in relation to treatment.

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Critical effects observed:

not specified

Conclusions:

Oral administration of TMAP to rats for a period of twenty-eight consecutive days by gavage, resulted in toxicologically significant effects at 75 mg/kg/day (clinical signs related to CNS toxicity, decreased bw gain, lower food consumption, increased water consumption, increased clotting time (m), increased plasma AP, ALAT (f) and ASAT (f), reduced plasma protein and albumin, reduced plasma urea (f), distended stomach (m), increased liver weight (f), hepatocyte basophilia and enlargement (f)). Based on these observations, the NOAEL for repeated dose toxicity is set at 15 mg/kg bw/day.

Executive summary:

TMAP was administered by gavage in a 28-day repeated dose toxicity study (OECD 407) with rats (10/dose) at dose levels of 0, 5, 15 and 75 mg/kg bw/day. Toxicologically significant effects were observed at 75 mg/kg bw/day and included clinical signs related to CNS toxicity, decreased bodyweight gain, lower food consumption, increased water consumption, increased clotting time (m), increased plasma AP, ALAT (f) and ASAT (f), reduced plasma protein and albumin, reduced plasma urea (f), distended stomach (m), increased liver weight (f), hepatocyte basophilia and enlargement (f). Based on these observations, the NOAEL for repeated dose toxicity is set at 15 mg/kg bw/day.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

15 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Study performed according to EC/OECD guidelines and GLP principles.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

TMAP was administered by gavage in a 28-day repeated dose toxicity study (OECD 407) with rats (10/dose) at dose levels of 0, 5, 15 and 75 mg/kg bw/day. Toxicologically significant effects were observed at 75 mg/kg bw/day and included clinical signs related to CNS toxicity, decreased bodyweight gain, lower food consumption, increased water consumption, increased clotting time (m), increased plasma AP, ALAT (f) and ASAT (f), reduced plasma protein and albumin, reduced plasma urea (f), distended stomach (m), increased liver weight (f), hepatocyte basophilia and enlargement (f). Based on these observations, the NOAEL for repeated dose toxicity is set at 15 mg/kg bw/day. It is of note that TMAP is the same test substance as TMHP (tetramethylammonium hydrogen phthalate).

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
One study available.

Repeated dose toxicity: via oral route - systemic effects (target organ) digestive: liver; neurologic: central nervous system

Justification for classification or non-classification

Based on the observed adverse effects at the dose level of 75 mg/kg bw/day in the 28 -day repeated dose toxicity study in rats, tetramethylammonium hydrogen phthalate is classified as STOT RE cat 2 and has obligatory labelling requirements for repeated dose toxicity according to Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2011), -Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures.