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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
short-term repeated dose toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable without restriction because it was conducted according to the recommendations of EU method B.7.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995
Report Date:
1995

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))
Version / remarks:
Cited as Directive 84/449/EEC, B.7
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Test compound: TPS 32
Chemical name: di-t-dodecyl polysulfide
CAS no.: 68425-15-0
Source: EAP
Batch: 152319 (94_000858)
Sulfur content 31.07%

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female

Administration / exposure

Route of administration:
oral: gavage
Duration of treatment / exposure:
28 days
Frequency of treatment:
daily
Doses / concentrations
Remarks:
Doses / Concentrations:
50, 250, 1000mg/kg/d
Basis:

Control animals:
yes, concurrent vehicle
Details on study design:
Post-exposure period: 14 days

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:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
not examined
Details on results:
CLINICAL SIGNS AND MORTALITY
Ptyalism was observed in all animals of both sexes given 1000 mg/kg bw/day just after treatment. This finding was considered to be related to the test substance. During the recovery period, no clinical signs were observed. No clinical signs were noted in the other groups.
One female given 250 mg/kg bw/day was found dead on day 16. No clinical signs were observed prior to death. At macroscopic examination, dilatation with reddish coloration was noted for the lungs. No relevant findings were noted at microscopic examination. One female given 1000 mg/kg bw/day was found dead on day 5. Prior to death, piloerection, hypokinesia, dyspnea and loud breathing were noted. At macroscopic examination, foamy contents were found in the trachea as well as dilatation and reddish color was noted for the lungs. No relevant findings were noted at microscopic examination. Neither death was considered to be treatment related. No deaths occurred during the recovery period.

BODY WEIGHT AND WEIGHT GAIN
During the treatment period and the recovery period, the mean body weight gain was similar between treated and control animals.

FOOD CONSUMPTION
During the treatment and recovery periods, the mean food consumption was similar between treated and control animals.

HAEMATOLOGY
On week 4, a slightly higher erythrocyte count and hemoglobin concentration (+5% or +6% for males and females, respectively) was noted in animals of both sexes given 1000 mg/kg bw/day. This was associated with a slightly higher packed cell volume (+7% and +6%, for the males and females, respectively). These differences from controls were not seen after 2 weeks of recovery. Since these differences were minor and the individual values were within the range of the background historical data, this was considered not to be of toxicological importance. The other differences from controls noted among haematological parameters (including lymphocyte and neutrophil counts) were minor and lacked a dose-relationship. Accordingly, they were considered to be of no toxicological significance.

CLINICAL CHEMISTRY
In week 4, the differences from controls noted among blood biochemical parameters (including: sodium, chloride and calcium levels, albumin level, triglyceride and glucose) were minor, without similar trend in both sexes, lacked a dose-relationship and the individual values were within or close to the normal range of the historical data. Consequently, they were considered not to be of toxicological importance.

URINALYSIS
No differences from controls were noted at the end of the treatment period.

ORGAN WEIGHTS
At the end of the treatment period:
Lower mean absolute and relative mandibular lymph node weights were noted in the males (absolute: -29%,-22%,-36%; relative: -27%,-18%,-31%). This was not statistically significant, not dose-related and almost all the individual values were within the range of the control values. Thus, this was considered not to be of toxicological importance. Moreover, this could be explained, at least in part, by a very high absolute and relative mandibular lymph node weight in 1/6 control males (L29587).

Lower mean absolute and relative thymus weights were noted in the males and females (absolute: -2%,-8%,-15% respectively for the males given 50, 250 or 1000 mg/kg/day; -8%, -4%,-13% respectively for the females; relative: -1%,-4%,-9% respectively for the males; -1%,+3%,-7% respectively for the females). These differences were minor, not statistically significant, not dose-related in the females and all the individual values of the treated males, except 1/6 absolute value in the high dose-level group, were within the range of the control values. In the females, 2/6 absolute and 1/6 relative thymus weights were lower than the lowest respective control weight in the low and intermediate dose-level groups and 3/5 absolute and relative thymus weights were lower than the lowest respective control weights in the high doselevel group, whereas 1/5 absolute and 1/5 relative values were higher than the highest respective control values. Moreover no relevant macroscopic or microscopic findings were noted. Thus, this was considered not to be of toxicological importance.

Higher mean absolute and relative ovary weights were noted in the females; this attained statistical significance for the relative weight in the intermediate dose-level group (absolute: +26%,+5% respectively for the intermediate and high dose-level groups; relative: +9%,+35%,+13% respectively for the low, intermediate and high dose-level groups). As this lacked a dose-relationship it was considered to be of no toxicological importance and most probably related to the differences in the phases of oestrous cycle.

Higher mean absolute and relative thyroid gland weights were noted in the females given 1000 mg/kg/day, when compared with the controls (absolute: +12%; relative: +29%). This was not statistically significant and was not observed in the two lower dose-level groups, where lower mean absolute values were noted. Only 1/6 individual absolute and relative values were higher than the highest control value. Thus, this was considered not to be of toxicological importance.
Some other differences were noted between treated males and females and their respective controls: they were minor, not statistically significant, not dose-related and thus, they were considered not to be of toxicological importance.

At the end of the recovery period:
Higher mean absolute and relative kidney weights were noted for the females given 1000 mg/kg/day (absolute and relative:+8%), when compared to the respective controls. This was statistically significant only for the relative weight. In addition, only 2/6 individual absolute and 1/6 individual relative values were higher than the highest respective control values. As this minor difference was not seen after the treatment period, it was not considered to be of toxicological importance.

Higher mean absolute and relative mesenteric lymph node weights were noted for the males and females given 1000 mg/kg/day (absolute: +13%,+18% respectively; relative: +22%,+19% respectively), when compared to the respective controls. This was not statistically significant, except for the relative weight in the females, and the individual absolute and relative values, for the males, were within the range of the respective controls. In the females, 4/6 individual absolute and only 1/6 individual relative values were higher than the highest respective control values. In addition, this was not observed after the treatment period. Consequently, this was not considered to be of toxicological importance.

Statistically significant lower mean absolute and relative mandibular lymph node weights were noted in the females given 1000 mg/kg/day, when compared with their respective controls (absolute and relative:-21%). This was not seen after the treatment period. In addition, only 3/6 individual absolute and 2/6 individual relative values were lower than the lowest respective control values. Consequently, this was not considered to be of toxicological importance.

Lower mean absolute and relative ovary weights were noted in the females given 1000 mg/kg/day (-12% for both absolute and relative weights). This was not statistically significant. Only 2/6 individual absolute or relative values were lower than the lowest respective control values; moreover, higher mean weights were recorded after the treatment period. Thus, this was not considered to be of toxicological importance.

Higher mean absolute and relative spleen weights were noted for the females given 1000 mg/kg/day, when compared to the respective controls (absolute: +19%; relative: +17%). This was not statistically significant. In addition, only 3/6 individual absolute values were higher than the highest respective control value and all the individual relative values were within the range of the controls. Moreover, this was not seen after the treatment period. Thus, this was not considered to be of toxicological importance.

Statistically significant lower mean absolute and relative thyroid gland weights were noted in the females given 1000 mg/kg/day (absolute:-32%; relative:-37%). Only 3/6 individual absolute and 1/6 individual relative values were lower than the lowest respective control values. As higher mean thyroid gland weights were noted after the four week treatment period, this was not considered to be of toxicological importance.

GROSS PATHOLOGY
At the end of the treatment and recovery periods:
The few macroscopic findings encountered were those which are commonly recorded spontaneous changes in the untreated laboratory rat of this strain and age and thus were not considered to be of toxicological importance.

HISTOPATHOLOGY: NON-NEOPLASTIC
At the end of the treatment period:
Minimal to moderate acidophilic globules were found in the cortical tubular epithelium of the kidneys in 3/6 males given 50 mg/kg/day and in 5/6 males given 250 mg/kg/day; minimal to slight acidophilic globules were found in all treated males at 1000 mg/kg/day. This was not found in any male of the control group. The presence of acidophilic globules in the treated males was considered to be treatment-related. However it was not associated with any degeneration/necrosis of the cortical tubular epithelium. This was considered to be due to the well-known increase in accumulation of the sex-linked protein (alpha-2}µglobuline) in the lysosomes of the cortical tubular cells, following absorption of some chemicals and this species and sex-related abnormality was considered to be of no toxicological importance.
No evidence of reversibility was found after the recovery period, as minimal to moderate acidophilic globules were found in the cortical tubular epithelium of 5/6 treated males given 1000 mg/kg/day versus minimal acidophilic globules in 1/6 control males.

Few other microscopic findings were found in the surviving treated animais and not in the controls; due to their low incidence (1/6 or 1/5 or 2/6 animals), the absence of dose-relationship and the fact that they are commonly observed spontaneously in the untreated rat of this strain and age, they were considered to be of no toxicological importance.
These findings included:
. heart: minimal cardiomyopathy in 1/6 males given 1000 mg/kg/day,
. urinary bladder: slight cystitis and slight epithelial cell hyperplasia noted in one female given 1000 mg/kg/day,
. liver: minimal hepatocellular degeneration in 1/6 females given 50 mg/kg/day; slight haemorrhage in 1/6 females given 250 mg/kg/day; minimal tension lipidosis in 1/6 females given 50 mg/kg/day; minimal steatosis in 1/6 females given 250 mg/kg/day; minimal focal coagulative hepatocellular necrosis in 1/6 males given 50 mg/kg/day and slight focal coagulative hepatocellular necrosis in 1/6 males given 250 mg/kg/day; moderate multifocal hepatocellular degeneration/necrosis in 1/6 females given 250 mg/kg/day,
. adrenals: slight vacuolated cortical cells in 1/6 males given 1000 mg/kg/day,
. kidneys: slight leucohistiocytic pyelitis and slight urothelial cell hyperplasia in 1/5 females given 1000 mg/kg/day (the same female which showed cystitis, as above-mentioned); minimal dilated pelvis in 1/6 males given 250 mg/kg/day; slight dilated pelvis in 1/6 males given 250 mg/kg/day; moderate dilated pelvis in 1/6 males given 1000 mg/kg/day; minimal mineralization in 1/6 males and 1/5 females given 1000 mg/kg/day,
. lungs: minimal perivascular haemorrhage in 1/6 males given 50 mg/kg/day; minimal chronic interstitial pneumonia in 1/6 males given 1000 mg/kg/day; slight chronic interstitial pneumonia in 1/6 males and 1/6 females given 50 mg/kg/day and in 1/6 males given 250 mg/kg/day; moderate chronic interstitial pneumonia in 1/6 males given 50 mg/kg/day and in 1/5 females given 250 mg/kg/day.

All the other microscopic findings noted in control and treated animals were those which are commonly recorded spontaneous changes in the untreated laboratory rat of this strain and age and thus, considered to be of no toxicological importance.

HISTOPATHOLOGY: NEOPLASTIC (if applicable)


HISTORICAL CONTROL DATA (if applicable)


OTHER FINDINGS

Effect levels

Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: No treatment-related adverse effects at any dose level tested

Target system / organ toxicity

Critical effects observed:
no

Any other information on results incl. tables

No deaths related to the treatment occurred during the treatment period  or the recovery period. 
Ptyalism was observed in all the animals of both sexes given  1000mg/kg/day during the treatment period. Thereafter, during the  recovery period, no clinical signs were observed. 
During the treatment and the recovery periods, the mean food consumption  and body weight gain were similar between treated and control animals. No  abnormalities of toxicological importance were noted among haematological  and blood biochemical parameters, urinalysis, organ weights, macro- and  microscopic examinations.

Applicant's summary and conclusion

Conclusions:
The oral (gavage) administration of TPS 32 to Sprague-Dawley rats for four weeks at 50 or 250 mg/kg/day was well-tolerated. At 1000 mg/kg/day, ptyalism was noted only during the treatment period and not during the recovery period. Consequently, under the conditions of this study, the No Observable Adverse Effect Level (NOAEL) is 1000 mg/kg/day.
Executive summary:

An OECD TG 407 study was conducted using male and female Sprague-Dawley rats administered 0, 50, 250, or 1000 mg/kg bw/day of di-t-dodecyl polysulfides by daily gavage for 29 days;   a satellite group in the control and high-dose groups were monitored for two weeks for recovery.   Group sizes were 12/sex for the control and 1000 mg/kg bw/day groups, and 6/sex for 50 and 250 mg/kg bw/day groups.   

One female given 1000 mg/kg bw/day was found dead on day 5.   Prior to death, piloerection, hypokinesia, dyspnea and loud breathing were noted.   At macroscopic examination, foamy contents were found in the trachea as well as dilatation and reddish color was noted for the lungs.   No relevant findings were noted at microscopic examination.   One female given 250 mg/kg bw/day was found dead on day 16; however, no clinical signs were observed prior to death.   At macroscopic examination, dilatation with reddish coloration was noted for the lungs.   No relevant findings were noted at microscopic examination.   The probable cause of death of these two females might be regurgitation or misdosing, consequently these mortalities were not considered to be related to test substance toxicity. No deaths occurred during the recovery period.   Ptyalism was observed in all animals of both sexes given 1000 mg/kg bw/day just after treatment.   This finding was considered to be related to the test substance.   During the recovery period, no clinical signs were observed in the high dose group, and no clinical signs were noted in the other groups during the dosing phase of the study.   During the treatment and recovery periods, mean body weights and food consumption were similar between treated and control animals.   With respect to clinical pathology, on week 4, a slightly higher erythrocyte count and hemoglobin concentration (+5% or +6% for males and females, respectively) was noted in animals of both sexes given 1000 mg/kg bw/day.   This was associated with a slightly higher packed cell volume (+7% and +6%, for the males and females, respectively).   These differences from controls were not seen after 2 weeks of recovery.   These differences were not considered to be of toxicological significance.   There were no differences in hematology, blood chemistry and urinalysis measurements that were considered to be of toxicological importance.   Higher mean absolute and relative ovary weights were noted in the females, attaining statistical significance for the relative weight in the intermediate dose-level group (absolute: +26%, +5%, respectively for the intermediate and high dose-level groups; relative: +9%, +35%, +13%, respectively, for the low, intermediate and high dose-level groups).   Higher mean absolute and relative kidney weights were noted for the females given 1000 mg/kg bw/day (absolute and relative: +8%), when compared to the respective controls.  This difference was statistically significant for the relative weight only, and was not considered to be of toxicological importance.   Statistically significantly lower mean absolute and relative mandibular lymph node weights were noted in the females given 1000 mg/kg bw/day as compared to the controls.   Because this was not observed following the treatment period, it was not considered to be of toxicological importance.   Statistically significant lower mean absolute and relative thyroid gland weights were noted in the females given 1000 mg/kg bw/day (absolute: -32%; relative: -37%).   As higher mean thyroid weights were noted after the recovery period, this was not considered to be of toxicological importance.   At necropsy, there were no macroscopic findings considered to be of toxicological importance.   Microscopically, minimal to moderate acidophilic globules were found in the cortical tubular epithelium of kidneys in 3/6 males given 50 mg/kg bw/day and in 5/6 males given 250 mg/kg bw/day; minimal to slight acidophilic globules were found in all treated males at 1000 mg/kg bw/day.   These kidney findings were not observed in any males of the control group.   The presence of acidophilic globules in the treated males was considered to be treatment-related.   No evidence of reversibility was found after the recovery period, as minimal to moderate acidophilic globules were found in the cortical tubular epithelium of 5/6 treated males given 1000 mg/kg bw/day versus minimal acidophilic globules in 1/6 control males.   However it was not associated with any degeneration/necrosis of the cortical tubular epithelium. This was considered to be due to the well-known increase in accumulation of sex-linked protein (α2-µglobuline) in the lysosomes of the cortical tubular cells and this species   and sex-related abnormality was considered to be of no toxicological importance (Hard et al., 2009). Few other microscopic findings were noted, and due to their low incidence, the absence of a dose relationship, they were considered to be of no toxicological importance.   

The NOAEL for both males and females was 1000 mg/kg bw/day