Di(tetraethylammonium)hexahydroxoplatinate(IV)

Endpoint summary

Description of key information

No repeated dose toxicity study with HHPA-TEAH is available, thus the repeated dose toxicity is addressed with existing data on HHPA and TEAH as detailed in the ‘HHPA-TEAH ReadAcross justification’ document (Section 13.2). 

For the purpose of hazard assessment of HHPA-TEAH, the point of departure for the most sensitive endpoint of each constituent will be used for the DNEL derivation.

 

 

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 September 2014 - 30 June 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study, conducted according to GLP.

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, 97633 Sulzfeld, Germany.
- Age at study initiation: 67 days (at first test item administration).
- Weight at study initiation: males: 326.4 - 402.7 g; females: 189.4 - 246.0 g (at first test item administration).
- Fasting period before study: no data.
- Housing: animals were housed singly, except during the mating period.
- Diet (e.g. ad libitum): certified commercial diet, offered ad libitum.
- Water (e.g. ad libitum): tap water, offered ad libitum.
- Acclimation period: 8 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): room temperature of 22degC +/- 3degC (maximum range).
- Humidity (%): relative humidity of 55% +/- 15% (maximum range).
- Air changes (per hr): no data.
- Photoperiod (hrs dark / hrs light): 12 hours dark/12 hours light, about 150 lux.

IN-LIFE DATES:
From: July 2014.
To: 23 October 2014 (males); 14 November 2014 (females).

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: test item formulations were prepared once weekly and stored in a tightly closed container at room temperature (+10 to +25 degC) until use.

DIET PREPARATION
- Rate of preparation of diet (frequency): not applicable.
- Mixing appropriate amounts with (Type of food): not applicable.
- Storage temperature of food: not applicable.

VEHICLE
- Justification for use and choice of vehicle (if other than water): the test substance was found to be unstable in water and other aqueous vehicles. Stability for 7 days in corn oil was demonstrated in an identity and stability investigation, and thus corn oil was taken forward as the vehicle for this study.
- Concentration in vehicle: 20, 60 or 200 mg test item/mL vehicle.
- Amount of vehicle (if gavage): 5 mL/kg bw/day.
- Lot/batch no. (if required): Batch nos. 13249003 and 13249006, Caesar & Loretz GmbH, 40721 Hilden, Germany.
- Purity: no data.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples of approximately 10 mL were collected once weekly, at the time of preparation of the formulation, and analysed for homogeneity and concentration.

Duration of treatment / exposure:

Males were dosed from test days 1-35 (inclusive), including 2 weeks prior to mating, the mating period and approximately 2 weeks post-mating. Females were dosed from test day 1 (2 weeks prior to mating), throughout mating and gestation, until day 3 post-partum or the day before sacrifice (from test day 41 for the first sacrificed females to test day 58 for the last sacrificed female).

Frequency of treatment:

Once daily.

Remarks:

Doses / Concentrations:
100 mg/kg bw/day
Basis:
actual ingested

Remarks:

Doses / Concentrations:
300 mg/kg bw/day
Basis:
actual ingested

Remarks:

Doses / Concentrations:
1000 mg/kg bw/day
Basis:
actual ingested

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: dose levels were selected based a 14-day dose range finding study conducted at the same testing laboratory. In the dose range finding study, male and female rats were treated with 1000 mg test item/kg bw/day. No animal died prematurely, there were no test item-related adverse effects, and no test item-related changes noted at necropsy.
- Rationale for animal assignment (if not random): computer-generated randomisation programme.
- Rationale for selecting satellite groups: not applicable.
- Post-exposure recovery period in satellite groups: not applicable.
- Section schedule rationale (if not random): not applicable.

Positive control:

No.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: before and after dosing and, additionally, regularly throughout the working day (7:00 to 15:45 on Monday to Friday; 7:00 to 11:00 with a final check at 15:00 on Saturday and Sunday).
- Cage side observations included any behavioural changes, signs of illness or reaction to treatment. Skin/fur, eyes, mucous membranes, respiratory and circulatory systems, somatomotor activity and behaviour patterns were recorded, together with the onset, intensity and duration of any signs observed.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once weekly, once before the first administration and once a week thereafter.
- Signs recorded included: changes in skin, fur, eyes, mucous membranes; occurrence of secretions, excretions and autonomic activity; changes in gait, posture and response to handling; behavioural changes.

BODY WEIGHT: Yes
- Time schedule for examinations: males and females were weighed on the first day of dosing, weekly thereafter, and at termination. During gestations, females were weighed on days 0, 7, 14 and 20, within 24 hours of parturition (day 1 post-partum), and day 4 post-partum.

FOOD AND WATER CONSUMPTION:
- Food consumption for each animal determined: Yes.
- Food intake per animal was determined using the total amount of food given to and left by each animal.
- Drinking water consumption for each animal determined: Yes, by daily visual appraisal throughout the study.

OPHTHALMOSCOPIC EXAMINATION: No.

HAEMATOLOGY: Yes.
- Time schedule for collection of blood: at the end of the pre-mating period.
- Anaesthetic used for blood collection: Yes (ether).
- Animals fasted: Yes, overnight.
- How many animals: 5 males and 5 females randomly selected from each group.
- Parameters checked in Table 1 were examined.

CLINICAL CHEMISTRY: Yes.
- Time schedule for collection of blood: at the end of the pre-mating period.
- Animals fasted: Yes, overnight.
- How many animals: 5 males and 5 females randomly selected from each group.
- Parameters checked in Table 2 were examined.

URINALYSIS: No.

NEUROBEHAVIOURAL EXAMINATION: Yes.
- Time schedule for examinations: males: test day 36; females: during lactation, between test days 41 and 51.
- Dose groups that were examined: 5 males and 5 females randomly selected from each group.
- Battery of functions tested: see Table 3.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes.
- The weights of the organs in Table 4 of all animals were recorded before fixation. The organs or parts of organs in Table 5a of all animals were fixed in 7% formalin (apart from the testes and epididymides, fixed in Bouin's fixative). The organs or parts of organs in Table 5b of 5 randomly selected animals/sex/group were fixed in the same way.
HISTOPATHOLOGY: Yes.
- The organs in Table 6 of the 5 randomly selected animals/sex in the control and high-dose groups were examined histologically.

Other examinations:

No data.

Statistics:

Analysis of normal distribution and homogeneity of variances was performed using the Shapiro-Wilks test and the Bartlett test.
One-way analysis of variance was performed using Anova or the Kruskal-Wallis test.
Intergroup comparisons, in the case of significant differences, were made using the Dunnett test.
Statistical analyses of non-parametrical data were performed using Fisher's exact test or the Chi-squared test.

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):

no effects observed

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

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:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY
No test item-related premature deaths were reported. Two female rats (one from the low-dose group and one from the mid-dose group) died during laboratory examination on test day 15, but their deaths were considered as not test item-related.

There were no changes in behaviour, external appearance, faeces or other clinical signs in any treated group, or the control, at any point during the study.

BODY WEIGHT AND WEIGHT GAIN
There were no test item-related changes in body weight or body weight gain in male rats, in the pre-mating, mating, and post-mating periods, or in females during the pre-mating period, gestation and lactation.

FOOD AND WATER CONSUMPTION
No test item-related changes in food consumption were noted between the control groups and any treated rats. There was a statistically significant decrease in food consumption in mid-dose females during the second week of the test; this showed no dose-response relationship and was considered not to be related to treatment.

The consumption of drinking water, assessed by daily visual appraisal, was not altered by treatment.

FOOD EFFICIENCY
Not examined.

OPHTHALMOSCOPIC EXAMINATION
Not examined.

HAEMATOLOGY
Test item administration was not considered to have an influence on any of the measured haematological parameters in male or female rats. The following statistically significant changes were reported, but considered to be spontaneous and not test item-related:
- Increased number of eosinophil granulocytes in low- and high-dose males.
- Decreased number of eosinophil granulocytes in mid- and high-dose females.
- Decreased number of basophil granulocytes in mid-dose females.
All values were within the range of background data for the testing laboratory.

CLINICAL CHEMISTRY
No test item-related influence was noted on the measured clinical chemistry parameters in any male or female rats. The following statistically significant changes were reported, but considered to be spontaneous and not test item-related:
- Increased globulin content in mid-dose males and all females.
- Decreased albumin/globulin ratio in mid-dose males and all females.
- Decreased blood glucose in low- and high-dose males.
- Increased total protein in mid-dose males and all females.
- Increased sodium in all females.
All values were within or only marginally below the range of background data for the testing laboratory.

URINALYSIS
Not examined.

NEUROBEHAVIOUR
No adverse effects were reported in observational or functional screening or assessment of spontaneous motility in males or females in any treatment group.

ORGAN WEIGHTS
No test item-related change in organ weights was reported in any treatment group. A statistically significant decrease in absolute liver weight was noted in low-dose females. This was within the range of the background data for the testing laboratory.

GROSS PATHOLOGY
No test item-related changes were observed in macroscopic examination of the internal organs and tissues of all test animals.

HISTOPATHOLOGY
No microscopic changes in the examined organs or tissues were seen in any treated animals.

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No general systemic effects seen at highest tested dose

Critical effects observed:

not specified

Conclusions:

In an OECD Test Guideline 422 combined repeated dose and reproductive/developmental toxicity screening study in rats, involving the gavage administration of dihydrogen hexahydroxyplatinate for at least 35 days, no clinical signs of toxicity or any adverse pathological or histopathological effects were observed. The study NOAEL was the highest tested dose (1000 mg/kg bw/day).

Executive summary:

In a combined repeated dose toxicity and reproductive/developmental toxicity screening study, conducted according to OECD Test Guideline 422 and to GLP, CD rats (12/sex/group) were orally administered dihydrogen hexahydroxyplatinate by stomach tube (gavage) at doses of 0, 100, 300 or 1000 mg/kg bw/day. Males were dosed for 35 days (2 weeks pre-mating, during the mating period and for approximately 2 weeks post-mating). Females were dosed for 14 days pre-mating, through mating, gestation and up to post-partum day 3 (test day 41-58).

 

Daily administration of dihydrogen hexahydroxyplatinate by oral gavage to CD rats did not result in test item related mortality, clinical signs of toxicity, or changes in the body weight, food/water consumption, haematology or clinical chemistry parameters, or neurological observations at dose levels of up to 1000 mg/kg bw/day during the treatment period. There were no adverse treatment-related changes in organ weights, or following macroscopic examination and histopathology for the adult animals of either sex.

 

On this basis, a study NOAEL of 1000 mg/kg bw/day was established.

Reference 2

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

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

Adequacy of study:

key study

Study period:

18 September 2014 - 30 June 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study, conducted according to GLP.

Justification for type of information:

Information on read-across approach
Selected endpoints for the human health hazard assessment of di(tetraethylammonium)hexahydroxoplatinate (IV) (HHPA-TEAH) are addressed by read-across, using a combination of data on hexahydroxoplatinate (HHPA) and tetraethylammonium hydroxide (TEAH) (or its substance analogue tetramethylammonium hydroxide (TMAH)). This way forward is acceptable, since HHPA-TEAH has a narrow stability and rapidly dissociates to HHPA and TEAH in acidic (e.g. gastric) environment.

The hazard information of HHPA and TEAH (or TMAH) was obtained from existing REACH registration dossiers via a license-to-use obtained by the registrant.

Detailed information justifying this read-across approach and listing/summarising the available toxicity data of HHPA-TEAH, HHPA and TEAH respectively, are reported in the ‘HHPA-TEAH ReadAcross justification’ document attached in IU section 13.2.

For the purpose of hazard assessment of HHPA-TEAH, the point of departure for the most sensitive endpoint of each constituent will be used for the DNEL derivation.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, 97633 Sulzfeld, Germany.
- Age at study initiation: 67 days (at first test item administration).
- Weight at study initiation: males: 326.4 - 402.7 g; females: 189.4 - 246.0 g (at first test item administration).
- Fasting period before study: no data.
- Housing: animals were housed singly, except during the mating period.
- Diet (e.g. ad libitum): certified commercial diet, offered ad libitum.
- Water (e.g. ad libitum): tap water, offered ad libitum.
- Acclimation period: 8 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): room temperature of 22degC +/- 3degC (maximum range).
- Humidity (%): relative humidity of 55% +/- 15% (maximum range).
- Air changes (per hr): no data.
- Photoperiod (hrs dark / hrs light): 12 hours dark/12 hours light, about 150 lux.

IN-LIFE DATES:
From: July 2014.
To: 23 October 2014 (males); 14 November 2014 (females).

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: test item formulations were prepared once weekly and stored in a tightly closed container at room temperature (+10 to +25 degC) until use.

DIET PREPARATION
- Rate of preparation of diet (frequency): not applicable.
- Mixing appropriate amounts with (Type of food): not applicable.
- Storage temperature of food: not applicable.

VEHICLE
- Justification for use and choice of vehicle (if other than water): the test substance was found to be unstable in water and other aqueous vehicles. Stability for 7 days in corn oil was demonstrated in an identity and stability investigation, and thus corn oil was taken forward as the vehicle for this study.
- Concentration in vehicle: 20, 60 or 200 mg test item/mL vehicle.
- Amount of vehicle (if gavage): 5 mL/kg bw/day.
- Lot/batch no. (if required): Batch nos. 13249003 and 13249006, Caesar & Loretz GmbH, 40721 Hilden, Germany.
- Purity: no data.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples of approximately 10 mL were collected once weekly, at the time of preparation of the formulation, and analysed for homogeneity and concentration.

Duration of treatment / exposure:

Males were dosed from test days 1-35 (inclusive), including 2 weeks prior to mating, the mating period and approximately 2 weeks post-mating. Females were dosed from test day 1 (2 weeks prior to mating), throughout mating and gestation, until day 3 post-partum or the day before sacrifice (from test day 41 for the first sacrificed females to test day 58 for the last sacrificed female).

Frequency of treatment:

Once daily.

Remarks:

Doses / Concentrations:
100 mg/kg bw/day
Basis:
actual ingested

Remarks:

Doses / Concentrations:
300 mg/kg bw/day
Basis:
actual ingested

Remarks:

Doses / Concentrations:
1000 mg/kg bw/day
Basis:
actual ingested

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: dose levels were selected based a 14-day dose range finding study conducted at the same testing laboratory. In the dose range finding study, male and female rats were treated with 1000 mg test item/kg bw/day. No animal died prematurely, there were no test item-related adverse effects, and no test item-related changes noted at necropsy.
- Rationale for animal assignment (if not random): computer-generated randomisation programme.
- Rationale for selecting satellite groups: not applicable.
- Post-exposure recovery period in satellite groups: not applicable.
- Section schedule rationale (if not random): not applicable.

Positive control:

No.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: before and after dosing and, additionally, regularly throughout the working day (7:00 to 15:45 on Monday to Friday; 7:00 to 11:00 with a final check at 15:00 on Saturday and Sunday).
- Cage side observations included any behavioural changes, signs of illness or reaction to treatment. Skin/fur, eyes, mucous membranes, respiratory and circulatory systems, somatomotor activity and behaviour patterns were recorded, together with the onset, intensity and duration of any signs observed.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once weekly, once before the first administration and once a week thereafter.
- Signs recorded included: changes in skin, fur, eyes, mucous membranes; occurrence of secretions, excretions and autonomic activity; changes in gait, posture and response to handling; behavioural changes.

BODY WEIGHT: Yes
- Time schedule for examinations: males and females were weighed on the first day of dosing, weekly thereafter, and at termination. During gestations, females were weighed on days 0, 7, 14 and 20, within 24 hours of parturition (day 1 post-partum), and day 4 post-partum.

FOOD AND WATER CONSUMPTION:
- Food consumption for each animal determined: Yes.
- Food intake per animal was determined using the total amount of food given to and left by each animal.
- Drinking water consumption for each animal determined: Yes, by daily visual appraisal throughout the study.

OPHTHALMOSCOPIC EXAMINATION: No.

HAEMATOLOGY: Yes.
- Time schedule for collection of blood: at the end of the pre-mating period.
- Anaesthetic used for blood collection: Yes (ether).
- Animals fasted: Yes, overnight.
- How many animals: 5 males and 5 females randomly selected from each group.
- Parameters checked in Table 1 were examined.

CLINICAL CHEMISTRY: Yes.
- Time schedule for collection of blood: at the end of the pre-mating period.
- Animals fasted: Yes, overnight.
- How many animals: 5 males and 5 females randomly selected from each group.
- Parameters checked in Table 2 were examined.

URINALYSIS: No.

NEUROBEHAVIOURAL EXAMINATION: Yes.
- Time schedule for examinations: males: test day 36; females: during lactation, between test days 41 and 51.
- Dose groups that were examined: 5 males and 5 females randomly selected from each group.
- Battery of functions tested: see Table 3.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes.
- The weights of the organs in Table 4 of all animals were recorded before fixation. The organs or parts of organs in Table 5a of all animals were fixed in 7% formalin (apart from the testes and epididymides, fixed in Bouin's fixative). The organs or parts of organs in Table 5b of 5 randomly selected animals/sex/group were fixed in the same way.
HISTOPATHOLOGY: Yes.
- The organs in Table 6 of the 5 randomly selected animals/sex in the control and high-dose groups were examined histologically.

Other examinations:

No data.

Statistics:

Analysis of normal distribution and homogeneity of variances was performed using the Shapiro-Wilks test and the Bartlett test.
One-way analysis of variance was performed using Anova or the Kruskal-Wallis test.
Intergroup comparisons, in the case of significant differences, were made using the Dunnett test.
Statistical analyses of non-parametrical data were performed using Fisher's exact test or the Chi-squared test.

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):

no effects observed

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

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:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY
No test item-related premature deaths were reported. Two female rats (one from the low-dose group and one from the mid-dose group) died during laboratory examination on test day 15, but their deaths were considered as not test item-related.

There were no changes in behaviour, external appearance, faeces or other clinical signs in any treated group, or the control, at any point during the study.

BODY WEIGHT AND WEIGHT GAIN
There were no test item-related changes in body weight or body weight gain in male rats, in the pre-mating, mating, and post-mating periods, or in females during the pre-mating period, gestation and lactation.

FOOD AND WATER CONSUMPTION
No test item-related changes in food consumption were noted between the control groups and any treated rats. There was a statistically significant decrease in food consumption in mid-dose females during the second week of the test; this showed no dose-response relationship and was considered not to be related to treatment.

The consumption of drinking water, assessed by daily visual appraisal, was not altered by treatment.

FOOD EFFICIENCY
Not examined.

OPHTHALMOSCOPIC EXAMINATION
Not examined.

HAEMATOLOGY
Test item administration was not considered to have an influence on any of the measured haematological parameters in male or female rats. The following statistically significant changes were reported, but considered to be spontaneous and not test item-related:
- Increased number of eosinophil granulocytes in low- and high-dose males.
- Decreased number of eosinophil granulocytes in mid- and high-dose females.
- Decreased number of basophil granulocytes in mid-dose females.
All values were within the range of background data for the testing laboratory.

CLINICAL CHEMISTRY
No test item-related influence was noted on the measured clinical chemistry parameters in any male or female rats. The following statistically significant changes were reported, but considered to be spontaneous and not test item-related:
- Increased globulin content in mid-dose males and all females.
- Decreased albumin/globulin ratio in mid-dose males and all females.
- Decreased blood glucose in low- and high-dose males.
- Increased total protein in mid-dose males and all females.
- Increased sodium in all females.
All values were within or only marginally below the range of background data for the testing laboratory.

URINALYSIS
Not examined.

NEUROBEHAVIOUR
No adverse effects were reported in observational or functional screening or assessment of spontaneous motility in males or females in any treatment group.

ORGAN WEIGHTS
No test item-related change in organ weights was reported in any treatment group. A statistically significant decrease in absolute liver weight was noted in low-dose females. This was within the range of the background data for the testing laboratory.

GROSS PATHOLOGY
No test item-related changes were observed in macroscopic examination of the internal organs and tissues of all test animals.

HISTOPATHOLOGY
No microscopic changes in the examined organs or tissues were seen in any treated animals.

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No general systemic effects seen at highest tested dose

Critical effects observed:

not specified

Conclusions:

In an OECD Test Guideline 422 combined repeated dose and reproductive/developmental toxicity screening study in rats, involving the gavage administration of dihydrogen hexahydroxyplatinate for at least 35 days, no clinical signs of toxicity or any adverse pathological or histopathological effects were observed. The study NOAEL was the highest tested dose (1000 mg/kg bw/day).

The calculated NOAEL for di(tetraethylammonium)hexahydroxoplatinate(IV) based on the read-across strategy and taken into account the maximum content of dihydrogen hexahydroxyplatinate = 1000 mg/kg bw/day / 0.536 (weight %) = 1865 mg/kg bw/day

Executive summary:

In a combined repeated dose toxicity and reproductive/developmental toxicity screening study, conducted according to OECD Test Guideline 422 and to GLP, CD rats (12/sex/group) were orally administered dihydrogen hexahydroxyplatinate by stomach tube (gavage) at doses of 0, 100, 300 or 1000 mg/kg bw/day. Males were dosed for 35 days (2 weeks pre-mating, during the mating period and for approximately 2 weeks post-mating). Females were dosed for 14 days pre-mating, through mating, gestation and up to post-partum day 3 (test day 41-58).

 

Daily administration of dihydrogen hexahydroxyplatinate by oral gavage to CD rats did not result in test item related mortality, clinical signs of toxicity, or changes in the body weight, food/water consumption, haematology or clinical chemistry parameters, or neurological observations at dose levels of up to 1000 mg/kg bw/day during the treatment period. There were no adverse treatment-related changes in organ weights, or following macroscopic examination and histopathology for the adult animals of either sex.

On this basis, a study NOAEL for dihydrogen hexahydroxyplatinate of 1000 mg/kg bw/day was established.

The calculated NOAEL for di(tetraethylammonium)hexahydroxoplatinate(IV) based on the read-across strategy and taken into account the maximum content of dihydrogen hexahydroxyplatinate = 1000 mg/kg bw/day / 0.536 (weight %) = 1865 mg/kg bw/day

Reference 3

Endpoint:

repeated dose toxicity: oral, other

Remarks:

Part of a combined repeated dose study (OECD 422) with reproductive and developmental toxicity screening.

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

30 November 2016 - 6 October 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study conducted according to GLP

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 16291C1AES.
- Expiration date of the lot/batch: 01 October 2019.
- Purity test date: 27 October 2016.

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At +10°C to +25°C; under inert gas (argon), in a tightly closed container in a dry place, protected from heat and direct sunlight.
- Stability under test conditions: Stable under prescribed storage conditions.
- Solubility and stability of the test substance in the solvent/vehicle: Satisfactory stability of suspensions of the test material in corn oil for 7 days has been previously demonstrated (LPT Report No. 33687).

Species:

rat

Strain:

Crj: CD(SD)

Details on species / strain selection:

The rat is a commonly used rodent species for such studies.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, 97633 Sulzfeld, Germany
- Females (if applicable) nulliparous and non-pregnant: Yes.
- Age at study initiation: 80 days.
- Weight at study initiation: Males: 404.3 g - 475.3 g / Females: 220.8 g - 279.9 g
- Fasting period before study: No.
- Housing: Housed singly, except during mating period.
- Diet (e.g. ad libitum): Certified commercial diet, provided ad libitum.
- Water (e.g. ad libitum): Tap water provided ad libitum.
- Acclimation period: 5 days.

DETAILS OF FOOD AND WATER QUALITY: Samples of both food and water are analysed periodically for quality; certificates of analysis were provided with the study report.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C +/- 3°C.
- Humidity (%): 55% +/- 15%.
- Air changes (per hr): 15-20 changes/hour/
- Photoperiod (hrs dark / hrs light): 12 hours dark/12 hours light (150 lux at approximately 1.5m room height).

IN-LIFE DATES: First application 20 December 2016 (aged 80 days). End of in-life period: 21 February 2017.

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: The test item formulations were prepared once weekly and stored in a tightly closed container at room temperature (+10°C to +25°C) until use.

VEHICLE
- Justification for use and choice of vehicle (if other than water): Standard non-aqueous vehicle for formulating suspensions.
- Concentration in vehicle: 20, 60 or 200 mg/mL.
- Amount of vehicle (if gavage): 5 mL/kg bw.
- Lot/batch no. (if required): Batch nos. 16260301 or 15422602, Caesar & Loretz GmbH, 40721 Hilden, Germany
- Purity: not specified.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analysis of homogeneity and concentration conducted weekly on 3 triplicate samples (total 9 samples), immediately after preparation of the test item-vehicle formulations.

Duration of treatment / exposure:

Males: 2 weeks prior to mating (test days 15-29), during the mating period (maximum test days 30-43) and until test day 50.
Females: 2 weeks prior to mating (test days 15-29), during the mating period (maximum test days 30-43) and during the lactation period until test days 64-77 (corresponding to lactation days 13-15).

Frequency of treatment:

Once daily.

Dose / conc.:

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

Remarks:

Vehicle control

Dose / conc.:

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

Remarks:

"low dose"

Dose / conc.:

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

Remarks:

"intermediate dose"

Dose / conc.:

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

Remarks:

"high dose"

No. of animals per sex per dose:

10.

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
The dose levels were selected by the Sponsor based on available toxicological data and a 14-day dose range finding study (LPT Study No. 33687).

In the 14-day dose range finding study, Dihydrogen hexahydroxyplatinate / 2-amino-ethanol (1:2) concentrate was administered orally to male and female rats at dose levels of 500, 750 or 1000 mg/kg b.w./day for 2 weeks. At 750 mg/kg b.w./day a slight reduction in body weight was noted for the female animals (at maximum 6.1% below the value of the control group, statistically not significant). At 1000 mg/kg b.w./day slight reductions in body weight were noted for the male and female animals, statistically significant only for the female animals (6.7% below the value of the control group, p ≤ 0.05). Furthermore, a slight but statistically significant reduction in food consumption was noted for the male animals during the first test week (12.3% below the value of the control group, p ≤ 0.05).

No changes in behavior or the external appearance were noted. No findings were noted during the macroscopic inspection at necropsy. The organ weights of the kidneys, the liver, the testes and / or the ovaries revealed no test item-related differences between the control group and the test item-treated groups. Based on the data obtained in this dose range finding study, dose levels of 100, 300 and 1000 mg Dihydrogen hexahydroxyplatinate / 2-amino-ethanol (1:2) concentrate/kg b.w./day were selected for the main study (LPT Study No. 33738).

Positive control:

Not applicable.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: At least once daily
- Cage side observations checked included skin/fur, eyes, mucous membranes, respiratory and circulatory systems, somatomotor activity and behaviour patterns. The onset, intensity and duration of any signs observed were recorded.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Once before first administration and once weekly thereafter.

BODY WEIGHT: Yes
- Time schedule for examinations: Males and females were weighed on the first day of dosing, weekly thereafter and at termination. During gestation, females were weighed on days 0, 7, 14 and 20 and within 24 hours of parturition (day 1 post-partum), and on days 4 and 13 post-partum.

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: Not applicable (compound dosed by gavage)

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: Not specified

WATER CONSUMPTION AND COMPOUND INTAKE: Drinking water consumption was monitored daily by visual appraisal throughout the study

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: At the end of the pre-mating period (test day 29)
- Anaesthetic used for blood collection: Yes (isoflurane)
- Animals fasted: Yes (overnight)
- How many animals: 5/sex/group, selected randomly
- Parameters checked in tables 1 and 2 were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At the end of the pre-mating period (test day 29)
- Animals fasted: Yes (overnight)
- How many animals: 5/sex/group, selected randomly
- Parameters checked in table 3 were examined.

THYROID HORMONE (T4) DETERMINATION
- Time schedule for collection of blood: At least 2 surplus pups/litter, from all litters, on post-natal day (PND) 4; at least 2 pups/litter, from all litters, on PND 13; all evaluated dams and all adult males at scheduled sacrifice

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: Two hours after dosing. 5 males/group (randomly selected) were evaluated on test day 45; 5 females/group were evaluated between lactation days 13 and 15.
- Dose groups that were examined: All
- Battery of functions tested: See table 4

IMMUNOLOGY: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (see table 5)

HISTOPATHOLOGY: Yes (see table 6)

Statistics:

Parametrical data: Homogeneity of variances and normality of distribution were tested using the BARTLETT’s and SHAPIRO-WILKS test. In case of heterogeneity and/or nonnormality of distribution, stepwise transformation of the values into logarithmic or rank values was performed prior to ANOVA. If the ANOVA yielded a significant effect (p ≤ 0.05), intergroup comparisons with the control group were made by the DUNNETT’s test (p ≤ 0.01 and p ≤ 0.05).

Non-parametrical data: The statistical evaluation of non-parametrical values was done using the FISHER or Chi-Squared test:
FISHERs exact test, n < 100; (p ≤ 0.05 and p ≤ 0.01); or
Chi-Squared test, n ≤ 0.01 (p ≤ 0.05 and p ≤ 0.01)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Males
Salivation (slight, incidental (low-dose) or slight-to-pronounced (intermediate- and high-dose)) reported in 1/10, 5/10 and 10/10 animals in the low-, intermediate- and high-dose animals, respectively.
No other clinical signs observed in the low-dose group. Piloerection and haemorrhagic nose/snout, and breathing sounds were each observed in 1/10 intermediate-dose animals but considered incidental on the basis of incidence.
Incidental haemorrhagic nose/snout was also reported in 1/10 high-dose animals. Breathing sounds were noted in 4/10, and slightly reduced motility in 10/10 high-dose animals.

Females
Slight to pronounced salivation was reported in in 2/10 intermediate-dose and 9/10 high-dose animals. In the high-dose group, slightly reduced motility was reported in 10/10 animals, and breathing sounds were noted in 1/10 animals.
No clinical signs were observed in low-dose females.

Mortality:

no mortality observed

Description (incidence):

No premature death was noted in the control group or in the treatment groups.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Males
A slightly-reduced body weight compared to controls was recorded from test day 29 (4.6% below controls, not statistically significant) until sacrifice (test day 51, 8.6% below controls, not statistically significant). Body weight gain for high-dose males was "clearly below" the control group for the whole treatment period (test days 15-51; 3.8% gain for high-dose animals vs. 13.2% in controls). At autopsy, high-dose males had a body weight 9.4% below controls (not statistically significant).

Females
Slight, but statistically not significant, reductions in body weight were reported in high-dose females at the end of gestation and during lactation (6.5% below controls on gestation day 20, 5.8% below controls on lactation day 1 and 5.0% below controls on lactation day 13). At autopsy, high-dose females had a body weight 2.4% below controls (not statistically significant).

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

Males
A slight, statistically not significant, reduction in food intake was noted during the first 2 weeks of dosing in the high-dose group (9.0% and 6.0% below controls).

Females
A statistically not significant reduction in food intake was noted in high-dose animals during the first week of dosing (8.1% below controls). A reduction was also seen in the high-dose animals throughout the gestation period (10.5% below controls in the first week (statistically significant), 7.4% below controls in the second week (not statistically significant) and 10.0% below controls in the third week (statistically significant). A slight but statistically significant reduction in food consumption was also noted in intermediate-dose animals during the third week of gestation (8.1% below controls). This was not considered by the study authors as test item-related.

Food efficiency:

not examined

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

no effects observed

Description (incidence and severity):

No test item-related changes in the consumption of drinking water was noted by visual appraisal for any treated rats.

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Description (incidence and severity):

No test item-related influence was noted on the haematological parameters of the male and female animals in any of the treatment groups.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

No test item related influence was noted for the examined plasma levels of the biochemical parameters in any of the treatment groups.

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

No observations of abnormal behaviour or test item-related differences in body temperature or the hind-leg splay in comparison to the control group were noted for the male and female animals of all treatment groups. No test item-related influence on the fore- and hindlimb grip strength or in spontaneous motility was noted for the male and female animals in any of the treatment groups.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

No test item-related influence was noted for the relative or absolute organ weights of the male or female animals in any of the test item-treated groups.

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Males
5/10 high-dose animals showed ulcers or thickened and/or discoloured cardiac stomach. These observations were confirmed by microscopic examination in 2/5 animals (the stomachs of the other 3/5 affected animals were not examined microscopically). However, these findings could be related to the deposition of the test item and were not considered as an adverse effect of the test item.

Females
No test item-related macroscopic changes reported in any treated females.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Males
Test item-related stomach lesions were reported in high-dose animals. Specifically, 3/5 animals examined showed erosions in the glandular mucosa, haemorrhage, inflammation, pigment depositon and ulcers in 1/5, and inflammation of the submucosa of the forestomach in 1/5. However, these findings could be related to the deposition of the test item and were not considered as an adverse effect of the test item.
There were no test item-related microscopic changes in the reproductive organs of the male animals. The histopathological examination that was performed on one testicle and one epididymis (with special emphasis on the qualitative stages of spermatogenesis (proliferative, meiotic and spermiogenic phases) and histopathology of the interstitial testicular structure) did not reveal any test item-related effects.

Females
No test item-related microscopic findings were reported in the 5 high-dose females subjected to examination.
No test item-related microscopic changes could be observed in the reproductive organs for group 4 females that were examined microscopically. The mammary glands of females observed showed prominent mammary development.

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Description (incidence and severity):

No test item-related differences in thyroid (T4) hormone levels were noted between the male animals of the control group and the male animals of the treatment groups. Likewise, there were no test-item related differences between T4 levels in control or treated pups. Blood samples taken from treated dams at scheduled sacrifice were not analysed for T4 level.

Dose descriptor:

NOAEL

Remarks:

general (systemic) toxicity

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical signs

food consumption and compound intake

Critical effects observed:

not specified

Conclusions:

In an OECD Test Guideline 422 combined repeated dose toxicity and reproduction/developmental toxicity screening study in rats, conducted to GLP, dihydrogen hexahydroxyplatinate, compound with 2-aminoethanol, was administered by gavage for at least 28 days (males) or 50-63 days (females) at doses of 0, 100, 300 or 1000 mg/kg bw/day. Treatment-related adverse effects were observed in the high dose animals (including reduced motility, decreased food consumption and body weight). The NOAEL for systemic toxicity was established as 300 mg/kg bw/day.

Executive summary:

In a combined repeated dose toxicity and reproductive/developmental toxicity screening study, conducted according to OECD Test Guideline 422 and to GLP, CD rats (10/sex/group) were orally administered dihydrogen hexahydroxyplatinate, compound with 2-aminoethanol by stomach tube (gavage, in corn oil) at doses of 0, 100, 300 or 1000 mg/kg bw/day. Males were dosed for at least 28 days (14 days pre-mating, as well as during the mating and post-mating periods). Females were dosed for 14 days pre-mating, through mating, gestation (around 22 days) and up to post-natal day 13 (50 -63 days in total). Control animals received vehicle only.

In the high-dose group, animals demonstrated clinical signs of toxicity including salivation, breathing sounds and reduced motility, as well as decreased food consumption and body weight. Gross lesions to the stomach were also observed and confirmed by further microscopic examination, but might have arisen due to deposition of the test item and were not considered as an adverse effect of the test item.

The NOAEL for systemic toxicity was established as 300 mg/kg bw/day.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Species:

rat

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

sub-chronic toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)

GLP compliance:

no

Remarks:

method comparative to OECD TG 410

Specific details on test material used for the study:

TS: tetramethylammonium hydroxide 25%, Vehicle: water

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Type of coverage:

not specified

Vehicle:

water

Details on exposure:

The vehicle (distilled water) and test substance formulation was applied to the reservoir of a Hill Top Chamber (Hill Top Biolabs, Inc., Cincinnati, Ohio) which was placed on the animal's shaven back behind the shoulder blades. The chamber was held secure with an elastic cloth band fastened with Velcro.

Duration of treatment / exposure:

4 weeks

Frequency of treatment:

6 h/day, 5 d/wk

Dose / conc.:

2.5 mg/kg bw (total dose)

Remarks:

female

Dose / conc.:

5.5 mg/kg bw (total dose)

Remarks:

male and female

Dose / conc.:

10 mg/kg bw (total dose)

Remarks:

female

Dose / conc.:

50 mg/kg bw (total dose)

Remarks:

female and male

Dose / conc.:

120 mg/kg bw (total dose)

Remarks:

male

Dose / conc.:

250 mg/kg bw (total dose)

Remarks:

male

No. of animals per sex per dose:

10 males / 10 females

Control animals:

yes, concurrent vehicle

Details on study design:

The initial target dose levels were 0, 0.55, 5, 12 and 25% w/v. The dosages were administered 6 hours/day, 5 days/week, at a constant volume of 1 ml/kg bw. These dose levels were equivalent to 0, 5.5, 50, 120 and 250 mg/kg bw/day. On the first day of administration, all male rats in the 120 and 250 mg/kg bw groups died within 3 hours after dosing and one male in the 50 mg/kg group died at the end of the day. Therefore, the dose levels to be administered to the female rats were lowered and a total of 7 treatment groups (a vehicle control and 6 dose levels) were evaluated between both sexes.
Because of the early deaths, other design changes were implemented. In an attempt to determine a possible cause of test substance-induced toxicity/moribundity, blood samples were collected via the retroorbital plexus from five male and four female rats in the 5% dose level group for hematology and limited serum chemistry analysis on study Day 4 and 3, respectively. In addition, rats dying spontaneously within the first week of the study were subjected to a gross necropsy and any tissues with grossly observable lesions (excluding application site skin) were collected. After one week of treatment the rats that died (five in the 50 mg/kg dose group) were subjected to a complete necropsy and their tissues were preserved, regardless of gross appearance. At study termination (day29) all surviving rats were euthanized, a gross necropsy performed and all gross lesions were collected and preserved in 10% neutral buffered formalin for possible microscopic evaluation.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

All of the male rats in the 120 and 250 mg/kg bw dose groups died within 3 hours after treatment initiation. Clinical signs noted in a few of the rats in these groups were lethargy followed by convulsions, tremors, and death beginning within one and a half to 2 hours after administration of the first dose of the test substance. One female rat in the 50 mg/kg bw dose group exhibited hyperactivity and labored breathing. No overt clinical signs of toxicity were observed at the lower doses (males; 5.5 mg/kg bw: females; 2.5, 5.5 or 10 mg/kg bw).

Dermal irritation:

effects observed, treatment-related

Description (incidence and severity):

Skin irritation at the application site included erythema, edema and/or scabbing in all groups treated with the test substance. In addition, scabbing (i.e.; possible grooming irritation) was seen in all groups, including the controls, and was considered to be associated with the animal's instinctive grooming behavior occurring when the collars were removed on the weekends.

Mortality:

mortality observed, treatment-related

Description (incidence):

All of the male rats in the 120 and 250 mg/kg bw dose groups died within 3 hours after treatment initiation. The 50 mg/kg bw male and female rats died intermittently throughout the study with the longest survival being approximately 2 weeks. No deaths were observed at the lower doses (males; 5.5 mg/kg bw: females; 2.5, 5.5 or 10 mg/kg bw).

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No significant differences were seen in body weights, body weight gain or food consumption, except for a body weight gain reducetion in the 4 surviving high dose females at week 1.

Food consumption and compound intake (if feeding study):

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

No overt changes in chemistry were seen, with the possible exception of a moderate increase in alkaline phosphatase noted in the male rats in the 50 mglkg group.

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

No gross lesions were noted in any of the dead animals at 120 or 250 mg/kg bw dose. Gross lesions were noted in the rats at 50 mg/kg bw and included red lungs (2 rats), urinary bladder calculus (2 rats), red ovaries (2 rats), dark eye (1 rat) and small seminal vesicles (1 rat). Red ovaries were also observed in all surviving rats at the 10 mg/kg bw (10/10) and 4/10 at the 5.5 mg/kg bw dose levels.

Key result

Dose descriptor:

NOAEL

Effect level:

5.5 mg/kg bw/day

Based on:

test mat.

Sex:

male

Basis for effect level:

clinical signs

gross pathology

mortality

Key result

Dose descriptor:

NOAEL

Effect level:

2.5 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

clinical signs

gross pathology

mortality

Critical effects observed:

not specified

Conclusions:

In a repeated dose dermal toxicity study in rats, conducted by a method comparative to OECD TG 410, involving dermal application of tetramethylammonium hydroxide for 4 weeks clinical signs of toxicity and adverse histopathological effects were observed. Based on these findings, the NOAELs for repeated dose dermal toxicity were considered to be 5.5 mg/kg bw/day in male rats and 2.5 mg/kg bw/day in female rats.

Executive summary:

In a repeated dose dermal toxicity study, rats were exposed for 4 weeks (6 hours/day, 5 days/week) to tetramethylammonium hydroxide (TMAH) at doses of 0, 5.5, 50, 120 and 250 mg/kg bw/day in male rats and 0, 2.5, 5.5, 10 and 50 mg/kg bw/day in female rats. In addition to erythema, edema and/or scabbing observed at the application sites in all of the treated animals, red ovaries were observed in female rats at 5.5, 10 and 50 mg/kg bw/day, and red lungs, urinary bladder calculus, dark eye and small seminal vesicles in male and/or female rats at 50 mg/kg bw/day. Based on these findings, the NOAELs for repeated dose dermal toxicity were considered to be 5.5 mg/kg bw/day in male rats and 2.5 mg/kg bw/day in female rats.

Reference 2

Endpoint:

sub-chronic toxicity: dermal

Type of information:

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

Adequacy of study:

key study

Study period:

1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Justification for type of information:

Information on read-across approach
Selected endpoints for the human health hazard assessment of di(tetraethylammonium)hexahydroxoplatinate (IV) (HHPA-TEAH) are addressed by read-across, using a combination of data on hexahydroxoplatinate (HHPA) and tetraethylammonium hydroxide (TEAH) (or its substance analogue tetramethylammonium hydroxide (TMAH)). This way forward is acceptable, since HHPA-TEAH has a narrow stability and rapidly dissociates to HHPA and TEAH in acidic (e.g. gastric) environment.

The hazard information of HHPA and TEAH (or TMAH) was obtained from existing REACH registration dossiers via a license-to-use obtained by the registrant.

Detailed information justifying this read-across approach and listing/summarising the available toxicity data of HHPA-TEAH, HHPA and TEAH respectively, are reported in the ‘HHPA-TEAH ReadAcross justification’ document attached in IU section 13.2.

For the purpose of hazard assessment of HHPA-TEAH, the point of departure for the most sensitive endpoint of each constituent will be used for the DNEL derivation.

Reason / purpose for cross-reference:

read-across source

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)

GLP compliance:

no

Remarks:

method comparative to OECD TG 410

Specific details on test material used for the study:

TS: tetramethylammonium hydroxide 25%, Vehicle: water

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Type of coverage:

not specified

Vehicle:

water

Details on exposure:

The vehicle (distilled water) and test substance formulation was applied to the reservoir of a Hill Top Chamber (Hill Top Biolabs, Inc., Cincinnati, Ohio) which was then placed on the animal's shaven back behind the shoulder blades. The chamber was held secure with an elastic cloth band fastened with Velcro. The chamber and wrapping were removed 6 hours after dosing.

Duration of treatment / exposure:

4 weeks

Frequency of treatment:

6 h/day, 5 d/wk

Dose / conc.:

2.5 mg/kg bw (total dose)

Remarks:

female

Dose / conc.:

5.5 mg/kg bw (total dose)

Remarks:

male and female

Dose / conc.:

10 mg/kg bw (total dose)

Remarks:

female

Dose / conc.:

50 mg/kg bw (total dose)

Remarks:

female and male

Dose / conc.:

120 mg/kg bw (total dose)

Remarks:

male

Dose / conc.:

250 mg/kg bw (total dose)

Remarks:

male

No. of animals per sex per dose:

10 males / 10 females

Control animals:

yes, concurrent vehicle

Details on study design:

The initial target dose levels were 0, 0.55, 5, 12 and 25% w/v. The dosages were administered 6 hours/day, 5 days/week, at a constant volume of 1 ml/kg bw. These dose levels were equivalent to 0, 5.5, 50, 120 and 250 mg/kg bw/day. On the first day of administration, all rats in the 120 and 250 mg/kg bw groups died within 3 hours after dosing and one male in the 50 mg/kg group died at the end of the day. Therefore, a total of 7 treatment groups (a vehicle control and 6 dose levels) were evaluated between both sexes.
Because of the early deaths, other design changes were implemented. In an attempt to determine a possible cause of test substance-induced toxicity/moribundity, blood samples were collected via the retroorbital plexus from five male and four female rats in the 5% dose level group for hematology and limited serum chemistry analysis on study Day 4 and 3, respectively. In addition, rats dying spontaneously within the first week of the study were subjected to a complete necropsy and their tissues were preserved, regardless of gross appearance. At study termination (Day 29) all surviving rats were euthanized, a gross necropsy performed. All gross lesions were collected and preserved in 10% neutral-buffered formalin for possible microscopic evaluation.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

All of the male rats in the 120 and 250 mg/kg bw dose groups died within 3 hours after treatment initiation. Clinical signs noted in a few of the rats in these groups were lethargy followed by convulsions, tremors, and death beginning within one and a half to 2 hours after administration of the first dose of the test substance. One female rat in the 50 mg/kg bw dose group exhibited hyperactivity and labored breathing. No overt clinical signs of toxicity were observed at the lower doses (males; 5.5 mg/kg bw: females; 2.5, 5.5 or 10 mg/kg bw).

Dermal irritation:

effects observed, non-treatment-related

Description (incidence and severity):

Skin irritation at the application site included erythema, edema and/or scabbing in all groups treated with the test substance. In addition, scabbing (i.e.; possible grooming irritation) was seen in all groups, including the controls, and was considered to be associated with the animal's instinctive grooming behavior occurring when the collars were removed on the weekends.

Mortality:

mortality observed, treatment-related

Description (incidence):

All of the male rats in the 120 and 250 mg/kg bw dose groups died within 3 hours after treatment initiation. The 50 mg/kg bw male and female rats died intermittently throughout the study with the longest survival being approximately 2 weeks. No deaths were observed at the lower doses (males; 5.5 mg/kg bw: females; 2.5, 5.5 or 10 mg/kg bw).

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

No gross lesions were noted in any of the dead animals at 120 or 250 mg/kg bw dose. Gross lesions were noted in the rats at 50 mg/kg bw and included red lungs (2 rats), urinary bladder calculus (2 rats), red ovaries (2 rats), dark eye (1 rat) and small seminal vesicles (1 rat). Red ovaries were also observed in all surviving rats at the 10 mg/kg bw (10/10) and 4/10 at the 5.5 mg/kg bw dose levels.

Key result

Dose descriptor:

NOAEL

Effect level:

5.5 mg/kg bw/day

Based on:

test mat.

Sex:

male

Basis for effect level:

clinical signs

gross pathology

mortality

Key result

Dose descriptor:

NOAEL

Effect level:

2.5 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

clinical signs

gross pathology

mortality

Critical effects observed:

not specified

Conclusions:

In a repeated dose dermal toxicity study in rats, conducted by a method comparative to OECD TG 410, involving dermal application of tetramethylammonium hydroxide for 4 weeks clinical signs of toxicity and adverse histopathological effects were observed. Based on these findings, the NOAELs for repeated dose dermal toxicity of tetramethylammonium hydroxide were considered to be 5.5 mg/kg bw/day in male rats and 2.5 mg/kg bw/day in female rats.

The NOAEL of the structural analogue tetraethylammonium hydroxide (TEAH) is considered to be 10 mg/kg bw/day
The calculated NOAEL for di(tetraethylammonium)hexahydroxoplatinate(IV) based on the read-across strategy and taken into account the maximum content of TEAH = 10 mg/kg bw/day / 0.528 (weight %) = 18.94 mg/kg bw/day

Executive summary:

In a repeated dose dermal toxicity study, rats were exposed for 4 weeks (6 hours/day, 5 days/week) to tetramethylammonium hydroxide (TMAH) at doses of 0, 5.5, 50, 120 and 250 mg/kg bw/day in male rats and 0, 2.5, 5.5, 10 and 50 mg/kg bw/day in female rats. In addition to erythema, edema and/or scabbing observed at the application sites in all of the treated animals, red ovaries were observed in female rats at 5.5, 10 and 50 mg/kg bw/day, and red lungs, urinary bladder calculus, dark eye and small seminal vesicles in male and/or female rats at 50 mg/kg bw/day. Based on these findings, the NOAELs of tetramethylammonium hydroxide for repeated dose dermal toxicity were considered to be 5.5 mg/kg bw/day in male rats and 2.5 mg/kg bw/day in female rats.

The NOAEL of the structural analogue tetraethylammonium hydroxide (TEAH) is considered to be 10 mg/kg bw/day

The calculated NOAEL for di(tetraethylammonium)hexahydroxoplatinate(IV) based on the read-across strategy and taken into account the maximum content of TEAH = 10 mg/kg bw/day / 0.528 (weight %) = 18.94 mg/kg bw/day

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

10 mg/kg bw/day

Species:

rat

Organ:

liver

thymus

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Mode of Action Analysis / Human Relevance Framework

no data identified

Additional information

Information on read-across approach

Selected endpoints for the human health hazard assessment of di(tetraethylammonium)hexahydroxoplatinate (IV) (HHPA-TEAH) are addressed by read-across, using a combination of data on hexahydroxoplatinate (HHPA) and ditetraethylammonium hydroxide (TEAH) (or its substance analogue tetramethylammonium hydroxide (TMAH)). This way forward is acceptable, since HHPA-TEAH has a narrow stability and rapidly dissociates to HHPA and TEAH in acidic (e.g. gastric) environment.

The hazard information of HHPA and TEAH (or TMAH) was obtained from existing REACH registration dossiers via a license-to-use obtained by the registrant.

Detailed information justifying this read-across approach and listing/summarising the available toxicity data of HHPA-TEAH, HHPA and TEAH respectively, are reported in the ‘HHPA-TEAH ReadAcross justification’ document attached in IU section 13.2.

 

 

Repeated dose toxicity 

Since no repeated dose toxicity study with HHPA-TEAH is available, information on its dissociation products HHPA and TEAH will be used for the hazard assessment and the risk characterisation of HHPA-TEAH.

Key repeated dose information from read-across substances:

NOAEL for systemic toxicity, oral, from a combined repeated dose and reproduction/developmental screening in rats: 1000 mg HHPA/kg bw/day.

NOAEL for systemic toxicity, dermal (read-across TMAH repeated dose, dermal): 10 mg TEAH/kg bw/day.

 

 

 

 

 

 

Justification for classification or non-classification

TEAH is classified STOT-RE 1 for dermal exposure according to CLP Regulation (EC) No. 1272/2008. Relevant target organs are thymus, and liver.

As the generic concentration limit triggering classification of a mixture is ≥ 10%, HHPA-TEAH is also classified STOT-RE 1 for dermal exposure.