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Toxicological information

Repeated dose toxicity: oral

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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: Well reported study, non-guideline, non-GLP. Endpoint study record transfered from Draft EU Risk Assessment, 2008

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1981
Report Date:
1981
Reference Type:
publication
Title:
A Subchronic Toxicity Study of Fyrol PCF in Sprague-Dawley Rats
Author:
Freudenthal RI, Henrich RT
Year:
1999
Bibliographic source:
International Journal of Toxicology April 1999 vol. 18 no. 3 173-176; doi: 10.1080/109158199225468

Materials and methods

Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
To determine the toxic effects of the test substance in rats when administered in the diet for three months. Four dose levels were used. Clinical signs were observed twice daily and food consumption and body weight were determined weekly. Clinical chemistry and haematology were determined at initiation, mid-study and termination; urinanalysis was conducted midstudy and at termination. Gross pathology and histopathology were also perfomed. In addition, a measure of brain cholinesterase was performed at the end of the study.
GLP compliance:
no
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Test material form:
liquid
Specific details on test material used for the study:
Fyrol PCF
lot no ERC-4800-3-10
tris(2-chloroisopropyl)phosphate 70%, 2-chloropropanol phosphate 23%
Stored at ambient temperature

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River LAbs, Wilmington Mass
- Age at study initiation: 6 weeks
- Weight at study initiation: males 186-243g; females 121-160
- Fasting period before study: no
- Housing: individually housed
- Diet (e.g. ad libitum): Purina certified rodent chow blended with 1% Mazola corn oil , ad libitum
- Water (e.g. ad libitum): tap water ad libitum
- Acclimation period: two weeks


ENVIRONMENTAL CONDITIONS
- Temperature (°C): not given
- Humidity (%): not given
- Air changes (per hr): not given
- Photoperiod (hrs dark / hrs light): not given


IN-LIFE DATES: From:11 Dec 1979 To: 14 Mar 1980

Administration / exposure

Route of administration:
oral: feed
Vehicle:
other: rat feed
Details on oral exposure:
rats were fed diets containing 0, 800, 2500, 7500 and 20000 ppm of TCPP for a period of thirteen weeks. This corresponds to mean substance intake values of 0, 52, 160, 481, and 1349 mg/kg/day for males and 0, 62, 171, 570, and 1745 mg/kg/day for females
Analytical verification of doses or concentrations:
not specified
Details on analytical verification of doses or concentrations:
Samples of the blended diet were analysed for homogeneity and concentration of the test substance. The results were:

low dose: 6 Dec 1979; 5 samples; 910 +- 53 ppm; 9 Jan 1980; 10 samples; 710+-40 ppm
low intermediate dose: 6 Dec 1979; 5 samples; 2500+-310ppm; 9 Jan 1980; 10 samples 2100+-47ppm
high intermediate dose: 6 Dec 1979; 5 samples; 7700+-160ppm; 9 Jan 1980; 10 samples; 7500+-190ppm
high dose: 6 Dec 1979; 5 samples; 21000+-550; 9 Jan 1980; 10 samples; 2000 +-1300ppm
Duration of treatment / exposure:
13 weeks
Frequency of treatment:
daily
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
0 ppm
Basis:
nominal in diet
Remarks:
Doses / Concentrations:
800 ppm
Basis:
nominal in diet
Remarks:
Doses / Concentrations:
2500 ppm
Basis:
nominal in diet
Remarks:
Doses / Concentrations:
7500 ppm
Basis:
nominal in diet
Remarks:
Doses / Concentrations:
20000 ppm
Basis:
nominal in diet
No. of animals per sex per dose:
20
Control animals:
yes, plain diet

Examinations

Observations and examinations performed and frequency:
Animals were observed for clinical signs twice daily and food consumption and weight gain was measured weekly. Blood samples were taken for clinical chemistry (including plasma and erythrocyte acetylcholinesterase concentration) and haematological measurements at initiation of the study, at the midpoint and at termination. Urine samples were taken for urinalysis at six weeks and at termination.
The following parameters were determined:
Haematology: packed cell volume; haemoglobin concentration; total erythrocyte, leukocyte and platelet counts; mean corpuscular volume; mean corpuscular haemoglobin; mean corpuscular haemoglobin concentration; blood smears for differential leukocyte counts.

Clinical Chemistry: BUN; LDH; ALT; AST; inorganic phosphate; Alkaline phosphatase; creatinine; direct and total bilirubin; cholesterol; glucose; albumin ; total protein; Na, K, Cl, Ca.

Urinanalysis:colour; turbidity; specific gravity; pH; protien; glucose; ketones; bilirubin; urobilogen. Sediment was examined microscopically.
Sacrifice and pathology:
Complete necropsy was carried out after terminal sacrifice.
The brain, adrenals, heart, liver, kidneys, gonads and thymus were weighed at study termination. Additional tissues and all significant gross lesions were collected as specified in the protocol. All tissue samples were routinely processed, sectioned at 5µm and stained with hematoxylin and eosin. Samples of all tissues from high dose and control animals were examined microscopically. Liver, kidney, heart, thyroid and all significant gross lesions from low and mid-dose animals were examined microscopically.
Other examinations:
Brain cholinesterase activity was measured at termination.
Statistics:
Body and organ weights , food consumption and clinical pathology determinants are reported individually and summarised as the group mean( +- standard deviation) according to treatment and sex. Quantal data, such as clinical observations, gross pathology observations and histopathology findings are reported individually and summarized in incidence tables.
Data summarised as means were analysed statisticallyusing one-way analysis of variance. When significant effects were indicated by the analysis of variance, Dunnett's method for multiple comparisons with control was applied. Differences were considered significant when p< 0.05

Results and discussion

Results of examinations

Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not specified
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
no effects observed
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
no effects observed

Effect levels

open allclose all
Dose descriptor:
NOAEL
Effect level:
ca. 2 500 ppm
Based on:
test mat.
Sex:
female
Basis for effect level:
other: A NOAEL of 2500 ppm (equivalent to 171 mg/kg/day) is derived for females, based on increased liver weights observed in females dosed at 7500 ppm and above.
Dose descriptor:
LOAEL
Effect level:
ca. 800 ppm
Based on:
test mat.
Sex:
male
Basis for effect level:
other: see remarks on result
Remarks on result:
other:
Remarks:
Based on the increase in absolute and relative liver weights (16% on the low dose males compared to controls), accompanied by mild thyroid follicular cell hyperplasia, observed in males of all dose groups a LOAEL of 800 ppm (equivalent to 52 mg/kg/day) was established, but a clear dose response was only observed in the two highest dose groups.

Target system / organ toxicity

Critical effects observed:
yes
Lowest effective dose / conc.:
52 mg/kg bw/day (actual dose received)
System:
other: liver and thyroid
Organ:
other: increased liver weight in all dosed males, periportal hepatocyte swelling in the high dose group and mild thyroid follicular cell hyperplasia in males at all doses and females at the highest dose
Treatment related:
yes

Any other information on results incl. tables

There were no treatment-related mortalities. No clinical observations were considered to be related to treatment. A slight, but statistically significant (p<0.05) reduction in mean body weight was apparent from day 22 of the study until termination in the high dose males (7.75% less than controls at day 80) and from day 35 in high dose females (11.8% less than controls on day 80). The mean absolute and relative liver weights were statistically significantly (p<0.05) increased in all male groups given TCPP and in females given 7,500 ppm and 20,000 ppm. In males given 800 ppm the group mean relative hepatic weight exceeded the control group mean by 16%. The absolute liver weight in this low dose group was also 16% greater than control. Relative liver weight of males given 20,000 ppm exceeded the control mean by 41% (absolute liver weight was 31% greater than controls for this group). In females given 7500 and 20,000 ppm, the mean relative liver weight exceeded that of controls by 20% and 30% respectively. The only histopathological finding related to this was periportal hepatocyte swelling (hypertrophy) in the high dose groups (9/20 males and 8/20 females). 0/20 male and 5/20 female control animals showed liver periportal swelling. Relative kidney weights were statistically significantly (p<0.05) increased in males at the two highest doses (13% and 16% greater than control, respectively). There was some evidence of histopathological change in the renal cortical tubule with the finding of mild degenerative change (hyaline droplet formation) in the two highest dose groups in males (12 animals and 7 animals, respectively) and vacuolation in females dosed with the highest dose (4 animals, compared to 1 control animal). The hyaline droplet formation is a male rat specific nephropathy and is not relevant for humans. Mild thyroid follicular cell hyperplasia was recorded in males at all doses (0/20, 2/20, 2/20, 5/20, and 8/20 at 0, 800, 2,500, 7,500 or 20,000 ppm respectively). This was seen in 5/20 females of the 20,000 ppm group, compared to 0/20 in the control group. There were no significant alterations in clinical chemistry, haematology or urinalysis parameters and no treatment-related changes in plasma, erythrocyte or brain cholinesterase activity. A slightly excessive fatty infiltration indicative of mild bone marrow hypoplasia was seen in three high dose females.

Applicant's summary and conclusion

Executive summary:

In an oral repeated dose toxicity study the test substance was axdministered to rats (20/sex/group) at dietary concentrations of 0, 800, 2500, 7500 or 20000 ppm for three months. Rats given 20000 ppm showed significantly (p<0.05) reduced body weight at most weekly intervals from weeks 4 through 12 in the males and weeks 6 through 12 in the females. No other treatment related clinical signs were noted. Significantly (p<0.0.5) higher absolute and relative liver weights were found in male rats of all groups fed the test substance and female groups given 7500 and 20000 ppm. In this study, the toxicologic significance of this observation cannot be ascertained. mean relative kidney weights of male groups given 2500, 7500 and 20000 ppm were significantly (p<0.05) greater than that of controls. hepatic morphologic change considered related to treatment was found only in rats given 20000 ppm, and was characterized by very mild swelling of cells located in the peroportal region of the hepatic lobule. Very mild cortical tubular degenerative changes were found in kidneys of male rats given 7500 ppm and in both sexes given 20000 ppm. Sternal bone marrow of three female rats given 20000 ppm was very mildly hypoplastic. Very mild thyroid follicular hyperplasia was found in male rats in all groups given the test substance and in females given 20000 ppm. Evaluation of hematological and clinical chemistry data, as well as cholinesterase activity in the brain, plasma and erythrocytes showed no change related to treatment. There were no deaths attributed to treatment with the test substance.

Based on the increase in absolute and relative liver weights, accompanied by mild thyroid follicular cell hyperplasia, observed in males of all dose groups a LOAEL of 800 ppm (equivalent to 52 mg/kg/day) is derived from this study for males. A NOAEL of 2500 ppm (equivalent to 171 mg/kg/day) is derived for females, based on increased absolute and relative liver weights observed in females dosed at 7500 ppm and above.