Isodecyl diphenyl phosphate

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: Study was not performed according to GLP, but equivalent or similar to OECD408.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1986

Report date:

1986

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:

no

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Isodecyl diphenyl phosphate

EC Number:

249-828-6

EC Name:

Isodecyl diphenyl phosphate

Cas Number:

29761-21-5

Molecular formula:

C22H31O4P

IUPAC Name:

isodecyl diphenyl phosphate

Details on test material:

- Name of test material (as cited in study report): Santicizer 148
- Physical state: colorless liqiod
- Analytical purity: confidential information
- Lot/batch No.: confidential information

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratory, Portage, Michigan
- Age at study initiation: 36 days
- Weight at study initiation: males 106.3-143.5 g, females 104.8-133.3 g
- Fasting period before study: no data
- Housing: stainless steel mesh cages suspended over paper bedding
- Diet (e.g. ad libitum): ad libitum (Ralston Purina Rodent Chow No. 5002
- Water (e.g. ad libitum): ad libitum (St. Louis public water supply)
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.1-23.3°C (70-74 degrees FAHRENHEIT)
- Humidity (%):40-60%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 8 February 1983 To: 10 May 1983

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency): weekly
- Mixing appropriate amounts with (Type of food): Ralston Purina Rodent Chow No. 5002
- Storage temperature of food: room temperature

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Homogeneity of mixing was determined by analysis of duplicate samples taken from the top, middle and bottom of the mixer. Furthermore, the stability of Santicizer 148 in the diet was verified over a 14 day period at room temperature. Dose verification was performed by extraction using hexane and analysis with gas chromatography using an N-P detector.
Homogeneity analysis indicated less than 3% difference in average concentration beween levels of the mixer. Analysis after 14 days of storage gave values of -7.3% and -4.7% for the low and high doses, respectively.

Duration of treatment / exposure:

90 days

Frequency of treatment:

daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 ppm

Remarks:

Nominal in diet

Doses / concentrations 2

Dose / conc.:

140 ppm

Remarks:

Nominal in diet

Doses / concentrations 3

Dose / conc.:

1 400 ppm

Remarks:

Nominal in diet

Doses / concentrations 4

Dose / conc.:

7 000 ppm

Remarks:

Nominal in diet

No. of animals per sex per dose:

30 animals/sex/dose

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: no data
- Rationale for animal assignment (if not random): assignments made by a computer generated scheme, taking into account that there was no significant difference between group mean body weights for each sex, or in variability of weights within each group

Positive control:

not relevant

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily
- Cage side observations: mortality, clincial signs

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Blood was collected twice, in week 6/7 and 13/14
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: 10 randomly selected animals/sex/dose
- Parameters examined: total erythrocyte count (RBC, cells per mm3), total leukocyte count (WBC, cells per mm3), platelets (counts per mm3), hematocrit (HCT, %), hemoglobin level (Hgb, g/dL), red blood cell indices (MCV, u3; MCH, uug; MCHC, g/dL),
- Other: Animals used for week 6/7 sampling were euthanized and discarded without necropsy after sample collection was completed

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Blood was collected twice, in week 6/7 and 13/14
- Animals fasted: No data
- How many animals: 10 randomly selected animals/sex/dose
- Parameters examined: serum albumin, total protein, blood urea nitrogen (BUN), total bilirubin, direct bilirubin, glucose, glutamic pyruvic transaminase (SGPT/ALT), alkaline phosphatase, glutamic oxaloacetic transaminase (SGOT/AST), gamma glutamyl transpeptidase (Gamma-GT), creatinine, cholesterol (Chol), calcium, phosphorus, chloride, sodium and potassium

URINALYSIS: Yes
- Time schedule for collection of urine: Urine was collected twice, in week 6/7 and 13/14
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data
- Parameters examined: pH, presence of urine protein, blood, glucose, ketone, bilirubin, urobilirubin

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY:
Yes, detailed necropsies were performed on all rats including those which died spontaneously or were sacrificed at study termination. Organ weights were determined from brain, kidneys, liver, and testes with epididymides. The following tissues were preserved: aorta, adrenals, bone and bone marrow (tibio-femoral joint), brain, colon, esophagus, eyes, heart, kidneys, lesions/abnormal masses, liver, lung (with mainstem bronchi), lymph node (mesenteric), mammary gland, muscle (quadriceps femoris), nerve (sciatic), ovaries, pancreas, prostate, pituitary, salivary gland (submaxillary), skin, small intestine (duodenum, jejunum, ileum), spinal cord, spleen, stomach, testes with epididymides, thymus, thyroid/parathyroid, trachea, uterus (corpus and cervix), urinary bladder,

HISTOPATHOLOGY:
Yes, tissues from all control and high dose group rats were examined microscopally.

Other examinations:

not relevant

Statistics:

- Dunnet's test (two-tailed)
- Bartlett's test
- Analysis of variance
- Mann-Whitney test
- Bonferroni inequality procedure
- Fisher's Exact test

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):

effects observed, treatment-related

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

effects observed, treatment-related

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 SIGNS AND MORTALITY
No treatment-related effects observed.

BODY WEIGHT AND WEIGHT GAIN
Significant decreased body weight and body weight gain was observed in the highest dose level.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
Significant decreased food consumption was observed in the highest dose level, which explains the decreased body weight for this dose group.

HAEMATOLOGY
At the interim measurement after 6-7 weeks of exposure, red blood cell count and hematocrit were significantly decreased in male rats in the mid and high dose. As a consequence, the calculated values mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were significantly increased. In females, hematocrit and mean corpuscular colume were significantly decreased at 7000 ppm.
At the end of the study (13-14 weeks), red blood cell count and hematocrit values were significantly increased in males at the mid and high dose, in contrast to the findings at the interim measurement.Consequently, mean corpuscular hemoglobin and mean corpuscular hemoglobin were significantly decreased. Females showed decreased white blood cell count and increased red blood cell count and hematocrit at all doses. Consequently, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were decreased significantly.

CLINICAL CHEMISTRY
Serum gamma glutamyl transpeptidase was increased at the highest dose level at both interim measurement and after termination, and in the mid dose level at termination. At the interim measurement, cholesterol was increased in the mid level in males, and in the high doses in both males in females. At termination this effect was only significant in high dose males, while the observed increased cholesterol level in high dose females was not significant. Serum creatinine levels were significantly depressed in males from the mid and high dose group and in females from all dose groups. Serum glucose levels were decreased at the interim measurement at the highest dose males, and in males and females from the mid and hgh dose group at termination. Other significant deviations were within normal limits for rats and did not appear to show a dose-relationship.

URINALYSIS
Urine bilirubin and urobilinogen levels tended to be elevated in treated males following an apparent linear dose trend. A similar trend was observed for bilirubin in female rats, but less obvious for urobilinogen.

ORGAN WEIGHTS
In high dose males, significantly increased brain, kidney, and testes relative weight were observed, while relative liver weight was increased in mid and high dose males. In female animals, kidney relative weight was increased in the highest dose, while increased liver relative weights were observed in both mid and high dosed females. Observed increases in relative brain, kidney and testes weight were probably a result of the significant reduction in body weight and were not related to other observed effects. Absolute liver weight were significantly decreased in mid and high dose males and high dose females.

GROSS PATHOLOGY
There were no differences in the incidence of gross lesions in treated males and females when compared to the controls.

HISTOPATHOLOGY: NON-NEOPLASTIC
Hepatocellular hypertrophy and/or hyperplasia was observed in males from the mid and high dose and in females from the high dose. The lesion appeared to involve the periportal regions of the hepatic lobule, with extension into the midzonal region. Furthermore, brown pigment was present within the liver cells of high dose females, primarily observed within the cytoplasm of hypertrophic/hyperplastic hepatocytes. These brown pigments were also observed in the liver of two high dose males. Electron microscopy revealed that the hepatocellular hypertrophy appeared to have been due primarily to an increased amount of smooth endoplasmic reticulum.

HISTOPATHOLOGY: NEOPLASTIC (if applicable)
Not applicable

Effect levels

1

Dose descriptor:

LOAEL

Effect level:

140 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: haematology

2

Dose descriptor:

LOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: haematology

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Analysis of feed concentration showed measured concentrations were in agreement with nominal concentrations. Furthermore, uniformity of diet mixing was demonstrated to be adequate.

 

140 ppm - 150 ± 11 µg/g

1400 ppm - 1410 ± 62 µg/g

7000 ppm - 7280 ± 432 µg/g

Based on food consumption measurements, the following average doses could be calculated:

 

140 ppm - 10 mg/kg bw/day

1400 ppm - 100 mg/kg bw/day

7000 ppm - 500 mg/kg bw/day

Applicant's summary and conclusion

Conclusions:

In a 90-day repeated dose toxicity oral feeding study, IDDPP was found to cause significant effects on several haematology parameters at the lowest dose level of 140 ppm. In the mid and high dose, effects were observed on liver-related clinical parameters, relative liver weight, and histopathology of the liver. Based on these findings, it was not possible to derive a NOAEL. The LOAEL was 140 ppm or 10 mg/kg bw/day.

Executive summary:

A 90-day repeated dose toxicity oral feeding study was performed equivalent or similar to OECD408. Male and female rats were exposed to 0, 140, 1400, and 7000 ppm incorporated in the diet, resulting in doses of 0, 10, 100, and 500 mg/kg/bw/day. Rats were observed for mortality and clinical signs twice daily. Body weight and food consumption was determined weekly. Haematology, clinical chemstry and urinalysis were measured at an interim measurement (6 -7 weeks) ant at termination (13 -24 weeks). Gross necropsy was performed animals from all doses, histopathology on animals from the control and high dose group.

Observed effects were reduced body weight gain, reduced food consumption, alterations in numbers of circulating red blood cells and red blood cell indices, decreased white blood cell values, decreased creatinine and serum glutamic oxaloacetic transaminae (SGOT), increased gamma glutamyl transpeptidase (gamma-GT), urobilinogen, urine bilirubin, cholesterol and phosphorus levels, as well as increased liver weights and hepatocellular hypertrophy/hyperplasia and hepatocellular brown pigment. As the effects on haematology parameters occurred at the lowest dose level, it was not possible to derive a NOAEL. The LOAEL was 140 ppm or 10 mg/kg bw/day.