Tributyl citrate

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

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

Adequacy of study:

key study

Study period:

2001 - 2002

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

yes

Remarks:

Range-finding study: Only limited histopathology performed and no special neurotoxicity examination included

Principles of method if other than guideline:

Range-finding study: Only limited histopathology performed and no special neurotoxicity examination included

GLP compliance:

no

Remarks:

no GLP required (range-finding study for long-term toxicity)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Tributyl O-acetylcitrate

EC Number:

201-067-0

EC Name:

Tributyl O-acetylcitrate

Cas Number:

77-90-7

Molecular formula:

C20H34O8

IUPAC Name:

tributyl 2-acetoxypropane-1,2,3-tricarboxylate

Test material form:

other: liquid

Details on test material:

Name of test material (as cited in study report): ATBC
Substance type: pure active
Physical state: liquid

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

Daily via the diet

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 96.02, 287.50 and 961.16 mg/kg
Basis:
actual ingested

No. of animals per sex per dose:

10 m / 10 f

Control animals:

yes, plain diet

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
Observation for mortality/viability were recorded twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
Time schedule: At least once daily. Palpation for tissue masses were performed at least once weekly

BODY WEIGHT: Yes
Time schedule for examinations: Weekly during pre-test, treatment and before necropsy

FOOD CONSUMPTION AND COMPOUND INTAKE:
Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day

FOOD EFFICIENCY: no

WATER CONSUMPTION AND COMPOUND INTAKE: no

OPHTHALMOSCOPIC EXAMINATION: Yes
Time schedule for examinations: During acclimatization and during week 13
Dose groups that were examined: All groups during acclimatization and all animals of the control and high dose group during week 13

HAEMATOLOGY: Yes
Time schedule for collection of blood: week 13 weeks
Anaesthetic used for blood collection: yes (light isoflurane anaesthesia)
Animals fasted: Yes
How many animals: all (10 m / 10 f per group)
Parameters examined: Erythrocyte count, haemoglobin, haematocrit, MCV, RDW, MCH, MCHC, HDW, reticulocyte, reticulocyte maturity index, leukocyte count, differential leukocyte count, prothrombin time, partial thromboplastin time

CLINICAL CHEMISTRY: Yes
Time schedule for collection of blood: week 13
Animals fasted: Yes
How many animals: all (10 m / 10 f per group)
Parameters examined: Glucose, urea, creatinine, bilirubin (total), cholesterol, tryglicerides, phospholipides, ASAT, ALAT, LDH, CK, ALP, GGT, Sodium, potassium, chloride, calcium, inorganic phosphorus, protein (total), albumin, globulin, albumin/globulin ration

URINALYSIS: no

NEUROBEHAVIOURAL EXAMINATION: no

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, all organs, all groups
HISTOPATHOLOGY: Yes.

Statistics:

Dunnett-test (many to one t-test) based on a pooled variance estimate if variables can be assumed to follow a normal distribution
Steel-test (many-one rank test) was applied instead of the Dunnett-test when data were not assumed to follow a normal distribution
Fisher's exact test was applied for ophthalmoscopic data and macroscopic findings
Armitage/Cochran Trend Test was used for non-neoplastic lesions, if appropriate

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

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:

no effects observed

Details on results:

CLINICAL CHEMISTRY
In m and f at 1000 mg/kg bw/day, decreased bilirubin levels, decreased aspartate aminotransferase and lactate dehydrogenase activity, increased sodium level, decreased chloride and calcium levels, decreased globulin levels (which resulted in increased albumin/globulin ratio) were evident in m at 300 and 1000 mg/kg bw/d

ORGAN WEIGHTS
1000 mg/kg: increased liver weights in m and f

GROSS PATHOLOGY
1000 mg/kg: enlarged livers in 2 f

HISTOPATHOLOGY: NON-NEOPLASTIC
1000 mg/kg: minimal hepatocellular hypertrophy (non-adverse) in several animals

Effect levels

Dose descriptor:

NOAEL

Remarks:

1000 mg/kg bw/day

Effect level:

>= 1 000 mg/kg bw/day (actual dose received)

Based on:

other: actuel ingested

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Table: Summary of test item-related findings for ATBC

 

Intended test item intake (mg/kg bw/day)	0	100	300	1000
Clinical chemistry
Males (means)
Glucose (mmol/L)	4.886	6.124**	5.895**	5.784*
Bilirubin (µmol/L)	2.055	1.955	1.767	1.305**
ASAT (U/L)	82.37	76.37	71.90**	66.08**
LDH (U/L)	136.50	120.88	92.29**	91.27**
Sodium (mmol/L)	144.58	145.00	154.52**	153.72**
Chloride (mmol/L)	100.94	101.33	89.18**	89.25**
Calcium (mmol/L)	2.834	2.811	2.666**	2.694**
Globulin (g/L)	26.356	26.474	24.431**	24.123**
Alb/Glob ratio (rel, %)	1.590	1.640	1.727*	1.755**
Females (means)
Bilirubin (µmol/L)	2.795	2.346	2.057	1.642**
Organ weights
Liver (means)
Males (abs., gram)	8.83	9.30	9.58	10.86**
Males (rel., %)	2.34	2.38	2.51	2.86**
Females (abs., gram	5.88	6.12	5.80	7.10**
Females (rel., %)	2.65	2.71	2.76	3.03*
Macroscopic findings
Liver (no. affected/10)	0/10	0/10	0/10	2/10
Females: Enlarged
Histopathology
Liver (no. affected/10)
Males: Hepatocellular hypertrophy	1/10	0/10	6/10	5/10
Females: Hepatocellular hypertrophy	0/10	0/10	1/10	2/10

 

• * = 5% level (Anova and/or Dunnett-Test)
• ** = 1% level (Anova and/or Dunnett-Test)

 

Applicant's summary and conclusion

Conclusions:

Based on the results of this study, dose levels of 100, 300 and 1000 mg/kg bw/d were proposed for the subsequent 2-year combined chronic/carcinogenicity study. Slight effects seen at 1000 mg/kg bw/d were considered due to hepatic metabolism adaption. Thus the NOAEL for m and f in this study was given with 1000 mg/kg bw/d

Executive summary:

This 13-weeks dietary toxicity study with acetyl tributyl citrate (ATBC) in Wistar rats was designed as dose range finding study for a subsequent combined chronic/carcinogenicity study. In principle, the study was performed according to OECD Guideline 408, but with restricted histopathological organ examinations. The administration at target doses of 100, 300 and 1000 mg/kg bw/d resulted in no unscheduled deaths. No test item-related clinical signs were observed. Treatment-related findings were restricted to slight changes in clinical biochemistry (males were more affected than females) and slightly increased liver weights accompanied by minimal hepatocellular hypertrophy at 1000 mg/kg bw/d. The findings were considered to be due to hepatic metabolic adaption rather than as sign of toxicity. The highest dose of 1000 mg/kg bw can be regarded as NOAEL. The proposed dose levels for a subsequent combined chronic/carcinogenicity study were 100, 300 and 1000 mg/kg bw/d. It can be assumed that the same applies to tributyl citrate (CAS 77-94-1) as it is a near analogue to the test substance acetyl tributyl citrate.