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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
Study period:
Not specified.
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP study, no specific methodology followed although fully documented report available. Read across to Tris(methylphenyl) phosphate, CAS 1330-78-5 which is considered an appropriate structural analogue.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1974
Report Date:
1974

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
The administration of the TCP was performed with a metal probe six days a week ( rest period on Sundays) for three months continuously. The doses were divided into four steps: 30, 100. 300 and 1000 mg/kg.
The experiment vas conducted with a total of five groups, including the control group which was not administered TCP (administered only 5% solution of gum arabic).
GLP compliance:
no
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Tris(methylphenyl) phosphate
- Molecular formula (if other than submission substance): C21H21O4P
- Molecular weight (if other than submission substance): 368.3628
- Smiles notation (if other than submission substance): Cc1ccc(cc1)OP(=O)(Oc2ccc(C)cc2)Oc3ccc(C)c
- InChl (if other than submission substance): InChI=1/C21H21O4P/c1-16-4-10-19(11-5-16)23-26(22,24-20-12-6-17(2)7-13-20)25-21-14-8-18(3)9-15-21/h4-15H,1-3H3
- Structural formula attached as image file (if other than submission substance): See below
- Substance type: Organic multiconstituent
- Physical state: Liquid
- Analytical purity: not specified
- Impurities (identity and concentrations): not specified
- Composition of test material, percentage of components: not specified
- Isomers composition: synthesized from m-cresol (60 - 65%) and p-cresol (40 - 35%)
- Purity test date: not specified
- Lot/batch No.: Oyatsu Chemical Industry, Lot NO. K-193
- Expiration date of the lot/batch: not specified
- Radiochemical purity (if radiolabelling): not applicable
- Specific activity (if radiolabelling): not applicable
- Locations of the label (if radiolabelling): not applicable
- Expiration date of radiochemical substance (if radiolabelling): not applicable
- Stability under test conditions: not specified
- Storage condition of test material: not specified
- Other:

Test animals

Species:
rat
Strain:
other: SD-SLC
Sex:
male/female
Details on test animals and environmental conditions:
The experimental animals were SD-SLC rats 6 weeks of age (Shizuoka Experimental Animals), both male and female. Each group was composed of ten animals. The experimental animals were kept isolated from the outside world in cages at a temperature of 24 +/- 2°C and humidity of 55 +/- 5 %. During the first three weeks, five animals were kept in each of these aluminium cages with plain floors (450 x 340 x 200 mm). Thereafter, the number was reduced to 3-4 animals per cage. The feed was Cobalt 60 irradiated, sterilized (1.5-2.5 x 10 + 6 r ) CE-2 solid pellets (Nihon Kurea). Normal tap water was provided ad libitum for drinking.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: 5% gum arabic solution
Details on oral exposure:
TCP was made into an emulsion in 5% gum arabic solution and regulated to the necessary concentration of for doses of 0.5 ml/100g body weight.
Analytical verification of doses or concentrations:
no
Details on analytical verification of doses or concentrations:
None
Duration of treatment / exposure:
Three months
Frequency of treatment:
The administration of the TCP was performed by oral gavage six days a week (rest period on Sundays) for three months continuously.
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
30 mg/kg body weight
Basis:

Remarks:
Doses / Concentrations:
100 mg/kg body weight
Basis:

Remarks:
Doses / Concentrations:
300 mg/kg body weight
Basis:

Remarks:
Doses / Concentrations:
1000 mg/kg body weight
Basis:

No. of animals per sex per dose:
10
Control animals:
yes, concurrent vehicle
Details on study design:
The administration of the TCP was performed with a metal probe six days a week ( rest period on Sundays) for three months continuously. The doses were divided into four steps: 30, 100. 300 and 1000 mg/kg.
The experiment vas conducted with a total of five groups, including the control group which was not administered TCP (administered only 5% solution of gum arabic). The following parameters were assessed:

Measurement of Body Weight and Food and Water Intake
Urinalysis
Hematologic Study
Serum Biochemical Tests
Measurement of the Weights of the Internal Organs
Positive control:
None

Examinations

Observations and examinations performed and frequency:
Measurement of Body Weight and Food and Water Intake: The presence or absence of general symptoms and deaths was studied each day in the experimental animals throughout the course of the study. The body weight was measured each week and the food and water intake determined.

Urinalysis: The urinalysis was performed once a month. The pH, sugar, protein, ketone bodies and blood reactions (Lab sticks, Nihon EmusuCo.) were studied in five male and female animals each in the control group and the 1000 mg/kg administration group.

Haematologic study: After the termination of the three month administration the animals were put under ether anesthesia and blood was collected from the descending aorta. Part of the blood was treated with EDTA-3K to prevent coagulation and the erythrocyte count (RBC), leukocyte count (WBC), haemoglobin (Hb) and packed cell volume (pcv) (the above employed by an autoanalyzer-SMA/4A, "Technicon Company") were measured. In addition, Giesma staining was performed to to producestained blood specimens and the leukocyte types differentiated.

Serum biochemical tests: The serum was isolated from a large part of the blood collected and the blood sugar values (glucose), albumin values (Alb), total protein (TP), SGOT activity values (GOT), blood urea nitrogen (BUN), alkaline phosphatase activity values (ALP), uric acid amounts (UA) and concentratiols of electroly t e s , Na, K, Ca (the above employed an autoanalyzer-SMA12/60, "Technicon Co. ") were measured. Also, SGPT activity values (GPT, Reitman-Frankel method) were measured.
Sacrifice and pathology:
After collection of blood samples, the rats were sacrificed by exsanguination. Along with the macroscopic observation of the various internal organs, the liver, kidneys, spleen, heart, lungs, adrenal glands, testes and ovaries were removedand their wet weight determined. In addition to these organs, the cerebellum, pituitary, medulla, spinal cord, thymus gland, thyroid gland, pancreas, digestive tract, prostate gland, urinary bladder and uterus were investigated pathohistologically after fixing in 10% formalin, and sections were prepared by the usual methods and H-E staining.
Other examinations:
None
Statistics:
Not reported.

Results and discussion

Results of examinations

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):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
no effects observed
Ophthalmological findings:
not examined
Haematological findings:
effects observed, treatment-related
Clinical biochemistry findings:
effects observed, treatment-related
Urinalysis findings:
effects observed, treatment-related
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:
General symptoms and mortality rate: From the beginning of the administration period , there was a transienty excessive salivation seen in all animals in the 1000 mg/kg group immediately after administration. Similarly, in the 300 mg/kg and 100 mg/kg groups, several cases of transient excessive salivation were seen a short time after administration. This symptom continued until the termination of the administrations.
Around the 50th day of the administration, the temperature regulator malfunctioned and the temperature in the cages dropped slightly , so several animals in the various groups, including the control group, showed signs of nasal discharge and sneezing. Following shortly after the appearance of these symptoms, one or two animals in the various groups exhibited discharge from the eyes and swelling of the eyelids, but these symptoms
disappeared in 1-2 weeks.
Excluding the accidental death of one female in the 30 mg/kg group which was not related to the administration of TCP, no deaths were seen in the various groups.

Body weight: The suppression of body weight increases was noted in the males in the 1000 mg/kg group from one week after the start of administration. The suppression continued without recovery until the end of the administrations. A slight suppression of weight increasewas seen in the females of the same group from about the 40th day of administration but the suppression was not as marked as in the males. In the 30 and 300 mg/kg groups, the development of both the males and females equalled or exceeded that of the control group throughout the administration period. For approximately 10 days after the 50th day of administration, the various groups almost all showed a slight decrease in weight or suppression of increase, but since this occurred at the same time as the appearance of the symptoms of nasal discharge etc., it is thought that the temporary decrease in room temperature may have been the cause.

Food and Water Intake: No particular changes were seen the in intake of food and water throughout the administration period.

Urinalysis: The pH of the urine of the males of the 1000 mg/kg group tended to become alkaline after about the second month of administration, and the same tendency was seen in the female animals of this group from about the third month. However, no abnormalities were seen in the protein, sugar, ketone bodies or blood reactions.

Hematologic Tests: An increase or decrease was seen in the erythrocyte count, packed cell volume and amount of hemoglobin in both the males and females of the various administration groups, but no clear relationship with the dose was noted. However, the differences were not so large as to deviate greatly from the range of normal values. The leukocyte count in the female animals tended to increase as the doses administered were increased, but no abnormalities were seen in the types of leukocytes present.

Serum Biochemical Tests: Both the males and the females in the dosage groups above 300 mg/kg showed decreased albumin values and the A/G ratio was slightly decreased. A slight increase was seen in the BUN in the females in the dosage groups above 300 mg/kg, but this change was not noted in the males. The concentration of K tended to show slight increases in both the males and the females as the doses increased. Almost no changes were seen in the enzyme activity values of the various groups.

Dissection and weight of the primary organs: In the macroscopic examination at the time of dissection, one case of small testes was seen in the control group and one case in the 30 mg/kg group. Edema of the kidneys was seen in one male in the 300 mg/kg group and one animal in the 1000 mg/kg group exhibited large adrenal glands. Other than these, there were no remarkable changes. When the primary organs were weighed, the males and females of the administration groups showed a slight increase in relative liver weight. A slight increase in the relative kidney weight was also seen in the females. The weight of the adrenal glands was found to be increased in the females of the 1000 mg/kg group, but this change was not seen in the males. Other than these changes, the males in the 1000 mg/kg group showed a slight decrease in the relative weight of the spleen, heart and lungs, but this may have been related to the suppression of increase in body weight.

Pathohistologic tests - the primary results were as follows: Edema-like vacuolar degredation in the cerebrum, cellular infilltration of the [illegible], cellular infilltration and fibrosis in the heart, atrophy of the hepatic cells in the liver, vacuolar degeneration and the presence of localized points of cellular infilltration in the liver, slight proliferation of the bile ducts, interstitial cellular infiltration in the kidneys, hyaline casts, calcareous deposits in the renal tubules, appearance of large vacuoles in the adrenal glands of the males and decreased production of spermatocytesin the testes were found.
These changes were also seen in the control animals with no difference in frequency. No relationship with the dose administered was noted. The following are changes not seen in the control group: calcareous deposits in the alveoli of the lungs, limited chronic pancreatitis, bundle-like thickened strips in the adrenal glands of the females and lymphocyte infiltration of the prostate gland were seen, but with the exception of the changes in the adrenal glands, these changes were seen in only a few animals each; thus, correlation with the test drug was not assumed. However, a correlation with the dose of the drug administered was found with the bundle-like thickening seen in the adrenal g1ands. Because special functional tests were not performed regarding this change, its significance is not clear but it is thought that its clinical significance is comparatively small.
The following changes were seen in both the males and females in this experiment: slight increase in liver weight, decreased serum albumin values and a tendency to increased potassium concentration. The following changes were seen only in the females: increased adrenal gland weight in the 1000 mg/kg group, tendency to increased leukocyte count, increased kidney weight and increased blood urea nitrogen. These changes were always comparatively slight. They were not severe even in animals of the 1000 mg/kg group. However, it may be thought that the liver and kidneys were affected from the functional point of view. However, the following results were obtained when the pathohistologic investigation was carried out in detail. There were no abnormalities at all in the liver and kidneys. The adrenal glands of the females showed bundle-like strips of thickening which were taken to be significant. Nothing else significant was noted. The frequency of occurrence of these changes was low and the relation to function unclear. In other words, the various changes seen in this experiment did not show a significant correlation with the pathohistologic tests.
Therefore it may be considered that the changes seen with the highest dose of 1000 mg/kg were comparatively slight.

Effect levels

Key result
Dose descriptor:
NOEL
Effect level:
30 mg/kg bw/day (actual dose received)
Sex:
male/female
Basis for effect level:
other: see 'Remark'

Target system / organ toxicity

Key result
Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
An experiment was performed with the oral administration of doses of 30, 100, 300, and 1000 mg/kg TCP continuously for three months to male and female SD-SLC rats and the following results obtained: 1) As a symptom of intoxication throughout the period of administration of TCP, transient excessive salivation was seen but no other abnornnalities appeared. 2) A slight suppression in body weight was seen in both the males and females of th 1000 mg/kg group. 3) The results of the hematologic tests in the females showed a tendency to increased leukocyte count but no other abnormalities were seen. 4) Decreased albumin values and increased potassium concentrations were seen in both the males and females in the results of a serum biachemical tests. Increased blood urea nitrogen was seen in only the females. 5) The slight increases in the liver weight manifested a correlation with the dose administered. In addition, the kidney weight was increased in the females and the weight of the adrenal gland was increased in the females of the 1000 mg/kg group.
All of the above changes were comparatively slight and, even in the 1000 mg/kg group, the correlation of the changes with the pathohistologic tests showed that the changes were not severe.
Executive summary:

An experiment was performed with the oral administration of doses of 30, 100, 300, and 1000 mg/kg TCP continuously for three months to male and female SD-SLC rats. The physical changes seen in the animals were comparatively slight even at the highest dosage level and except for one animal that was killed accidentally, all animals survived to the end of the experiment. The NOEL is assigned at 30 mg/kg/bw.