Disodium dihydrogenpyrophosphate

Endpoint summary

Description of key information

Acute oral toxicity: The oral LD50 value is derived using a weight of evidence approach. Taking into account the five studies available on disodium dihydrogenpyrophosphate and the available studies on tetrapotassium pyrophosphate and tetrasodium pyrophosphate which are considered to be of similar systemic toxicity, the weight of evidence indicates that the oral LD50 is greater than the classification limit of 2000 mg/kg bw/day.
Acute inhalation toxicity: One key study is available to assess the acute inhalation toxicity of disodium dihydrogenpyrophosphate. Disodium dihydrogenpyrophosphate is considered to exhibit a low potential toxicity via the inhalation route and is not expected to be of significant concern. 
The key study (Signorin J, 1993) has been conducted according to the relevant guidelines (EU and US) and according to the principles of GLP. The acute inhalation median concentration (LC50) of disodium dihydrogenpyrophosphate in male and female rats was estimated to be > 0.58 mg/L (the maximum attainable concentration). 
Acute dermal toxicity: One Key study is available to assess the acute dermal toxicity of disodium dihydrogenpyrophosphate.  The key study (Bradshaw, 2010) has been conducted according to a current guideline (OECD Method 402) and according to the principles of GLP. The acute dermal median lethal dose (LD50) of the test material in the Wistar strain rat was found to be > 2000 mg/kg bodyweight and is therefore not considered to be classified in accordance with Regulation (EC) No. 1272/2008. In addition, a number of supporting studies on the analogous substances tetrapotassium pyrophosphate and tetrasodium pyrophosphate are provided to support the conclusion that sodium and potassium pyrophosphates exhibit low systemic toxicity.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

No data

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The test material was administered by gavage to Sprague-Dawley albino rats as a 25% aqueous solution suspension at dose rates of 2510, 3160, 3980 and 5010 mg/kg bw. Observations were made for toxic signs and the viscera of the test animals were examined macroscopically.

GLP compliance:

no

Remarks:

Study predates GLP

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
Body weights (the report does not specify when the body weight was measured): Males: 205 - 280 g; Females: 215 - 260 g


ENVIRONMENTAL CONDITIONS
No data


IN-LIFE DATES: No data

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
The test material was administered as a 25.0% aqueous solution suspension.


MAXIMUM DOSE VOLUME APPLIED: No data


DOSAGE PREPARATION (if unusual): No data

Doses:

2510, 3160, 3980 and 5010 mg/kg bw

No. of animals per sex per dose:

2510 mg/kg bw: 3 females and 2 males
3160 mg/kg bw: 2 females and 3 males
3980 mg/kg bw: 3 females and 2 males
5010 mg/kg bw: 2 females and 3 males

Control animals:

no

Details on study design:

- Duration of observation period following administration: up to 7 days after dosing
- Frequency of observations and weighing: No data
- Necropsy of survivors performed: yes

Observations were made for toxic signs and the viscera of the test animals were examined macroscopically.

Statistics:

No data

Preliminary study:

Not applicable

Sex:

male/female

Dose descriptor:

LD50

Effect level:

3 600 mg/kg bw

Mortality:

One female animal died at the 2510 and 3160 mg/kg dose levels.
Three females died at the 3980 mg/kg dose level.
All 5 animals died at the 5010 mg/kg dose level.

Survival time was one to two days.

Clinical signs:

other: Toxic signs included reduced appetite and activity (one to two days in survivors), increasing weakness, collapse and death.

Gross pathology:

At autopsy there were haemorrhagic areas of the lungs, areas of liver discolouration and acute gastrointestinal inflammation.
Surviving animals were sacrificed 7 days after dosing. The viscera appeared normal by macroscopic examination.

Other findings:

No data

Interpretation of results:

GHS criteria not met

Conclusions:

The single oral dose LD50 for male and female rats was 3600 mg/kg with lower and upper limits of 3180 to 4070 mg/kg.
According to the study report, the compound was classed as slightly toxic by oral ingestion in male and female rats. However, in accordance with Regultation (EC) No. 1272/2008 (REACH) disodium dihydrogenpyrophosphate is not considered to be classified via the oral route.

Reference 2

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

29th June 1973

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
See read-across justification report under Section 13 ‘Assessment Reports’.
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In accordance with REACH Annex XI, Section 1.5, of Regulation (EC) No. 1907/2006 (REACH) the standard testing regime may be adapted in cases where a grouping or read-across approach has been applied.

The similarities may be based on:
(1) a common functional group
(2) the common precursors and/or the likelihood of common breakdown products via physical or biological processes, which result in structurally similar chemicals; or
(3) a constant pattern in the changing of the potency of the properties across the category

The source and target substances are both inorganic salts of a monovalent cation from Group 1A of the periodic table, sodium or potassium, and pyrophosphoric acid. Thus, they all share the sodium or potassium cation and the pyrophosphate anion as common functional groups.
All members of the group will ultimately dissociate into the common breakdown products of sodium / potassium cations and the pyrophosphate anions.
Both the Na+ and the K+ cation have a similar biological function and therefore pyrophosphate salts of these types are considered to have a systemic toxicity profile. Differences arise in their local effects profile due to the increasing or decreasing acidity/alkalinity and buffering capacities of the substances. The pyrophosphate ion is the simplest form of a condensed phosphate group. The pyrophosphate can undergo ionisation with loss of H+ from each of the two –OH groups on each P and therefore can occur in the -1, -2 -3 or -4 states. The degree of ionisation is dependent upon the associated cations and the ambient pH (if in solution). Therefore, the above substances have a pyrophosphate anion that is likely to behave in a similar way.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
See read-across justification report under Section 13 ‘Assessment Reports’.

3. ANALOGUE APPROACH JUSTIFICATION
See read-across justification report under Section 13 ‘Assessment Reports’.

4. DATA MATRIX
See read-across justification report under Section 13 ‘Assessment Reports’.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

no guideline followed

Principles of method if other than guideline:

The diluted compound was fed by the stomach to male and female rats, after determining the minimal lethal dose, four seperate dose groups (mg/kg) were each administered as a 25% aqueous solution of the test material. Mortalities within 7 days were used to determine the LD50 value for the test material. Observations were also made for toxic signs and the viscera of the test animals were examined macroscopically.

GLP compliance:

no

Remarks:

predates GLP

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

no data

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 25% aqueous solution were prepared
- Amount of vehicle (if gavage): no data

MAXIMUM DOSE VOLUME APPLIED: 3980 mg/kg bw, 220 gm of test material

- Rationale for the selection of the starting dose: The minimal lethal dose was determined and used to derive a range of doses over which the LD50 would be determined

Doses:

2000 mg/kg; 2510 mg/kg; 3160 mg/kg; 3980 mg/kg

No. of animals per sex per dose:

5 animals per dose.
2000 mg/kg - 3 female, 2 male
2510 mg/kg - 2 female, 3 male
3160 mg/kg - 3 female, 2 male

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 7 days
- Necropsy of survivors performed: yes
- Other examinations performed: Clinical observations, the viscera were examined macroscopically and autopsy.

Statistics:

The LD50 was calculated according to the method of E. J. De Beer.

Sex:

male/female

Dose descriptor:

approximate LD50

Effect level:

2 980 mg/kg bw

95% CL:

> 2 740 - < 3 250

Mortality:

yes, see the table in the results section for further details

Clinical signs:

other: Toxic signs included reduced appetite and activity (one to two days in survivors), increasing weakness and collapse.

Gross pathology:

At autopsy there was hemorrhagic areas of the lungs, slight liver discolouration, and acute gastrointestinal inflammation. The viscera appeared normal by macroscopic examination

The single oral LD50 of tetrapotassium pyrophosphate

sample fed as a 25% aqueous solution

Animal No. – Sex	Weight gm	Dose mg/kg	Fate
1 – female	220	2000	survived
2 – male	205	2000	survived
3 – female	210	2000	survived
4 – male	215	2000	survived
5 – female	225	2000	survived
6 – male	235	2510	survived
7 – female	240	2510	died
8 – male	250	2510	survived
9 – female	240	2510	survived
10 – male	230	2510	survived
11 – female	260	3160	died
12 – male	215	3160	survived
13 – female	225	3160	died
14 – male	220	3160	died
15 – female	210	3160	survived
16 – male	210	3980	died
17 – female	220	3980	died
18 – male	215	3980	died
19 – female	220	3980	died
20 – male	210	3980	died

The compound was classed as slightly toxic by oral ingestion in male and female rats.

Survival time was one to two days.

Interpretation of results:

GHS criteria not met

Conclusions:

The single LD50 for male and female rats was placed at 2980 mg/kg bw, with upper and lower limits of 2740 and 3250 mg/kg bw respectively. Based on this result the compound was described as slightly toxic. In accordance with Regulation (EC) No. 1272/2008 tetrapotassium pyrophosphate is not considered to be toxic via the oral route.

Reference 3

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

The study was performed between 14 October 2009 and 17 November 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
See read-across justification report under Section 13 ‘Assessment Reports’.
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In accordance with REACH Annex XI, Section 1.5, of Regulation (EC) No. 1907/2006 (REACH) the standard testing regime may be adapted in cases where a grouping or read-across approach has been applied.

The similarities may be based on:
(1) a common functional group
(2) the common precursors and/or the likelihood of common breakdown products via physical or biological processes, which result in structurally similar chemicals; or
(3) a constant pattern in the changing of the potency of the properties across the category

The source and target substances are both inorganic salts of a monovalent cation from Group 1A of the periodic table, sodium or potassium, and pyrophosphoric acid. Thus, they all share the sodium or potassium cation and the pyrophosphate anion as common functional groups.
All members of the group will ultimately dissociate into the common breakdown products of sodium / potassium cations and the pyrophosphate anions.
Both the Na+ and the K+ cation have a similar biological function and therefore pyrophosphate salts of these types are considered to have a systemic toxicity profile. Differences arise in their local effects profile due to the increasing or decreasing acidity/alkalinity and buffering capacities of the substances. The pyrophosphate ion is the simplest form of a condensed phosphate group. The pyrophosphate can undergo ionisation with loss of H+ from each of the two –OH groups on each P and therefore can occur in the -1, -2 -3 or -4 states. The degree of ionisation is dependent upon the associated cations and the ambient pH (if in solution). Therefore, the above substances have a pyrophosphate anion that is likely to behave in a similar way.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
See read-across justification report under Section 13 ‘Assessment Reports’.

3. ANALOGUE APPROACH JUSTIFICATION
See read-across justification report under Section 13 ‘Assessment Reports’.

4. DATA MATRIX
See read-across justification report under Section 13 ‘Assessment Reports’.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 420 (Acute Oral Toxicity - Fixed Dose Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.1 bis (Acute Oral Toxicity - Fixed Dose Procedure)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of GLP inspection: 15 September 2009 Date of Signature on GLP certificate: 26 November 2009

Test type:

fixed dose procedure

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:
Harlan Laboratories UK Limited, Bicester, Oxon, UK

- Age at study initiation:
At the start of the study the animals were eight to twelve weeks of age.

- Weight at study initiation:
The bodyweight variation did not exceed ± 20% of the initial/mean bodyweight of any previously dosed animal(s).

- Fasting period before study:
overnight fast immediately before dosing

- Housing:
The animals were housed in groups of up to four in suspended solid floor polypropylene cages furnished with woodflakes.

- Diet (e.g. ad libitum):
(2014 Teklad Global Rodent diet supplied by Harlan Laboratories UK Limited, Bicester, Oxon, UK was allowed ad libitum throughout the study.

- Water (e.g. ad libitum):free access to mains drinking water

- Acclimation period:acclimatisation period of at least five days


ENVIRONMENTAL CONDITIONS
- Temperature (°C):
19 to 25°C

- Humidity (%):
30 to 70%

- Air changes (per hr):
The rate of air exchange was at least fifteen changes per hour.

- Photoperiod (hrs dark / hrs light):
lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve hours darkness.


IN-LIFE DATES: From: Day 1 To: Day 14

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
- Concentration in vehicle:
For the purpose of the study the test material was freshly prepared, as required, as a suspension in distilled water to give a dose levels of 300mg/kg and 2000mg/kg bodyweight.

- Amount of vehicle:
Not stated

- Justification for choice of vehicle:
Distilled water was the preferred vehicle of the test method.

- Lot/batch no.:
Not stated

- Purity:
Not stated


MAXIMUM DOSE VOLUME APPLIED:
10ml/kg


DOSAGE PREPARATION:
Not applicable

CLASS METHOD:
Not applicable

- Rationale for the selection of the starting dose:
Using available information on the toxicity of the test material, 2000 mg/kg was chosen as the starting dose.

Doses:

Following a sighting test at a dose level of 2000 mg/kg, an additional four fasted female animals were given a single oral dose of test material, as a suspension in distilled water, at a dose level of 2000 mg/kg bodyweight. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.
Due to mortality and signs of systemic toxicity at a dose level of 2000 mg/kg, a sighting animal was treated at a dose level of 300 mg/kg, an additional four fasted female animals were given a single oral dose of test material, as a suspension in distilled water, at a dose level of 300 mg/kg bodyweight. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

No. of animals per sex per dose:

1 female at 2000 mg/kg
4 females at 2000 mg/kg
1 female at 300 mg/kg
4 females at 300 mg/kg

Control animals:

no

Details on study design:

- Duration of observation period following administration:
14 days

- Frequency of observations and weighing:
Clinical observations were made ½, 1, 2, and 4 hours after dosing and then daily for fourteen days. Morbidity and mortality checks were made twice daily. Individual bodyweights were recorded on Day 0 (the day of dosing) and on Days 7 and 14.

- Necropsy of survivors performed:
Yes

- Other examinations performed:
Clinical signs, body weight.

Preliminary study:

A sighting test at a dose level of 2000 mg/kg was performed.
A sighting test at a dose level of 300 mg/kg was performed.

Sex:

female

Dose descriptor:

LD50

Effect level:

> 300 - < 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: 95% confidence limits not given in study report.

Mortality:

Dose Level - 2000 mg/kg:
One animal was humanely killed two days after dosing. Two animals were found dead three or seven days after dosing.

Dose Level - 300 mg/kg:
There were no deaths.

Clinical signs:

other: Dose level - 2000mg/kg: Signs of systemic toxicity noted were hunched posture, ataxia, lethargy, pilo erection, tiptoe gait and dehydration. Surviving animals appeared normal one or two days after dosing. Dose level - 300mg/kg No signs of systemic toxi

Gross pathology:

Dose level - 2000mg/kg:
Abnormalities noted at necropsy of the animal that was humanely killed or animals that died during the study were abnormally red lungs, dark liver or patchy pallor of the liver, dark kidneys, gaseous stomach and slight haemorrhage of the gastric mucosa. No abnormalities were noted at necropsy of animals that were killed at the end of the study

Dose level - 300mg/kg:
No abnormalities were noted at necropsy

Other findings:

- Organ weights:
Not recorded

- Histopathology:
EXAMPLE: Not recorded

- Potential target organs:
EXAMPLE: Not recorded

- Other observations:
EXAMPLE: None

Table1              Individual Clinical Observations and Mortality Data -2000mg/kg

Dose Level mg/kg	Animal Number and Sex	Effects Noted After Dosing (Hours)				Effects Noted During Period After Dosing (Days)
		½	1	2	4	1	2	3	4	5	6	7	8	9	10	11	12	13	14
2000	1-0 Female	0	0	0	0	H	0	Ä	0	0	0	0	0	0	0	0	0	0	0
	2-0 Female	0	HA	HAP	HAPWt	HAPLWt	HAPL WtDhX*
	2-1 Female	0	HAL	HALP	HALP	A	A	H	H	0	0	X
	2-2 Female	0	HA	HA	HA	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-3 Female	0	HAL	HAL	HALP	HA	HA	X

0= No signs of systemic toxicity

H = Hunched posture

A = Ataxia

L = Lethargy

P = Pilo‑erection

Wt = Tiptoe gait

Dh = Dehydration

X = Animal dead

X* = Animal humanely killed

Ä= Due to a technician error, observation not performed

Table2              Individual Bodyweights and Bodyweight Changes -2000mg/kg

Dose Level mg/kg	Animal Number and Sex	Bodyweight (g) at Day			Bodyweight (g) at Death	Bodyweight Gain (g) During Week
		0	7	14		1	2
2000	1-0 Female	182	184	199		2	15
	2-0 Female	171	-	-	158	-	-
	2-1 Female	186	-	-	162	-	-
	2-2 Female	165	174	189		9	15
	2-3 Female	174	-	-	150	-	-

Table3              Individual Necropsy Findings -2000 mg/kg

Dose Level mg/kg		Animal Number and Sex		Time of Death		Macroscopic Observations
2000		1-0 Female		Killed Day 14		No abnormalities detected
		2-0 Female		Humanely Killed Day 2		Liver: patchy pallor Stomach: gaseous Gastric mucosa: haemorrhagic, slight
		2-1 Female		Animal found dead Day 7		Lungs: abnormally red Liver: dark Kidneys: dark
		2-2 Female		Killed Day 14		No abnormalities detected
		2-3 Female		Animal found dead Day 3		Lungs: abnormally red Liver: patchy pallor Stomach: gaseous Gastric mucosa: haemorrhagic, slight

 

Table4              Individual Clinical Observations and Mortality Data -300mg/kg

Dose Level mg/kg	Animal Number and Sex	Effects Noted After Dosing (Hours)				Effects Noted During Period After Dosing (Days)
		½	1	2	4	1	2	3	4	5	6	7	8	9	10	11	12	13	14
300	3-0 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	4-0 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	4-1 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	4-2 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	4-3 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

 

0= No signs of systemic toxicity

Table5              Individual Bodyweights and Bodyweight Changes-300mg/kg

Dose Level mg/kg	Animal Number and Sex	Bodyweight (g) at Day			Bodyweight Gain (g) During Week
		0	7	14	1	2
300	3-0 Female	169	171	182	2	11
	4-0 Female	180	188	195	8	7
	4-1 Female	177	182	187	5	5
	4-2 Female	184	195	203	11	8
	4-3 Female	160	166	173	6	7

 

Table6              Individual Necropsy Findings-300mg/kg

Dose Level mg/kg	Animal Number and Sex	Time of Death	Macroscopic Observations
300	3-0 Female	Killed Day 14	No abnormalities detected
	4-0 Female	Killed Day 14	No abnormalities detected
	4-1 Female	Killed Day 14	No abnormalities detected
	4-2 Female	Killed Day 14	No abnormalities detected
	4-3 Female	Killed Day 14	No abnormalities detected

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

The acute oral median lethal dose (LD50) of the test material in the female Wistar strain rat was estimated to be in the range of 300 - 2000 mg/kg bodyweight (EU CLP - Category 4).

Executive summary:

Introduction. The study was performed to assess the acute oral toxicity of the test material in the Wistar strain rat. The method was designed to meet the requirements of the following:

OECD Guidelines for Testing of Chemicals No 420 “Acute Oral Toxicity - Fixed Dose Method” (2001)

Method B1bisAcute Toxicity (Oral) of CommissionRegulation (EC) No. 440/2008

Method. Following a sighting test at dose levels of 2000 mg/kg and 300 mg/kg, further groups of four fasted females were given a single oral dose of test material, as a suspension in distilled water, at dose levels of 2000 mg/kg and 300 mg/kg bodyweight. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

Mortality. Three animals treated at a dose level of 2000 mg/kg were humanely killed or found dead during the study. There were no deaths noted at a dose level of 300 mg/kg.

Clinical Observations. Signs of systemic toxicity noted in animals treated at a dose level of 2000 mg/kg were hunched posture, ataxia, lethargy, pilo-erection, tiptoe gait and dehydration. There were no signs of systemic toxicity noted at a dose level of 300 mg/kg.

Bodyweight. Surviving animals showed expected gains in bodyweight.

Necropsy. Abnormalities noted at necropsy of animals treated at a dose level of 2000 mg/kg that died during the study or was humanely killed were abnormally red lungs, dark liver or patchy pallor of the liver, dark kidneys, gaseous stomach and slight haemorrhage of the gastric mucosa. No abnormalities were noted at necropsy of animals that were killed at the end of the study.

Conclusion. The acute oral median lethal dose (LD₅₀) of the test material in the female Wistar strain rat was estimated to be in the range of 300 ‑ 2000 mg/kg bodyweight (EU CLP - Category 4).

Reference 4

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

No data

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Sodium acid pyrophosphate was administered to 5 rats at a dose of 1000 mg/kg bw.

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 228-250 g


ENVIRONMENTAL CONDITIONS
No data


IN-LIFE DATES: No data

Route of administration:

oral: unspecified

Vehicle:

not specified

Details on oral exposure:

VEHICLE
No data


MAXIMUM DOSE VOLUME APPLIED: The dose administered to the animals was between 2.3 and 2.5 mL. The concentration of the test material administered was 100 mg/mL of water.


DOSAGE PREPARATION (if unusual): No data

Doses:

1000 mg/kg

No. of animals per sex per dose:

5 animals

Control animals:

not specified

Details on study design:

No data

Statistics:

No data

Preliminary study:

Not applicable

Sex:

not specified

Dose descriptor:

LD50

Effect level:

> 1 000 mg/kg bw

Mortality:

No animals died during the course of the study.

Clinical signs:

other: No unusual clinical signs were observed.

Gross pathology:

No data

Other findings:

No data

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: not specified

Conclusions:

There were no mortalities and all animals appeared normal during the course of the study. Based on the results of the study, the LD50 is greater than 1000 mg/kg bw.
This study is not considered to be sufficient for classification and labelling in accordance with Regulation (EC) No. 1272/2008 and therefore the study cannot be assigned as reliable for use as a key study however the data is acceptable for use as part of a weight of evidence approach (as detailed in Annex XI, Section 1.2 of Regulation (EC) No. 1907/2006).

Reference 5

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Qualifier:

according to guideline

Guideline:

other: no data on methodology

Deviations:

not specified

Principles of method if other than guideline:

No data

GLP compliance:

no

Remarks:

Study predates GLP

Test type:

other: no data

Species:

mouse

Strain:

Swiss Webster

Sex:

male

Details on test animals or test system and environmental conditions:

No data

Route of administration:

oral: unspecified

Vehicle:

water

Details on oral exposure:

No data

Doses:

No data

No. of animals per sex per dose:

10 males

Control animals:

not specified

Details on study design:

No data

Statistics:

No data

Sex:

male

Dose descriptor:

LD50

Effect level:

2.3 other: g/kg

Mortality:

No data

Clinical signs:

other: No data

Gross pathology:

No data

Other findings:

No data

Interpretation of results:

study cannot be used for classification

Conclusions:

This study cannot be assigned as reliable for use as a key study however the data is acceptable for use as part of a weight of evidence approach (as detailed in Annex XI, Section 1.2 of Regulation (EC) No. 1907/2006).

Reference 6

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Qualifier:

according to guideline

Guideline:

other: no data on methodology in study report

Deviations:

not specified

Principles of method if other than guideline:

No data

GLP compliance:

no

Remarks:

Study predates GLP

Test type:

other: No data

Species:

rat

Strain:

Sprague-Dawley

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Simonsen Laboratories, Gilroy, California
- Weight at study initiation: 278-344 g
- Fasting period before study: overnight

Route of administration:

oral: unspecified

Vehicle:

water

Details on oral exposure:

No data

Doses:

No data

No. of animals per sex per dose:

10 male rats

Control animals:

not specified

Details on study design:

no data

Sex:

male

Dose descriptor:

LD50

Effect level:

1.8 other: g/kg

Mortality:

No data

Clinical signs:

other: No data

Gross pathology:

No data

Other findings:

No data

Interpretation of results:

study cannot be used for classification

Conclusions:

Documentation insufficient for assessment therefore, the study cannot be assigned as reliable for use as a key study however the data is acceptable for use as part of a weight of evidence approach (as detailed in Annex XI, Section 1.2 of Regulation (EC) No. 1907/2006).

Reference 7

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

No data.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
See read-across justification report under Section 13 ‘Assessment Reports’.
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In accordance with REACH Annex XI, Section 1.5, of Regulation (EC) No. 1907/2006 (REACH) the standard testing regime may be adapted in cases where a grouping or read-across approach has been applied.

The similarities may be based on:
(1) a common functional group
(2) the common precursors and/or the likelihood of common breakdown products via physical or biological processes, which result in structurally similar chemicals; or
(3) a constant pattern in the changing of the potency of the properties across the category

The source and target substances are both inorganic salts of a monovalent cation from Group 1A of the periodic table, sodium or potassium, and pyrophosphoric acid. Thus, they all share the sodium or potassium cation and the pyrophosphate anion as common functional groups.
All members of the group will ultimately dissociate into the common breakdown products of sodium / potassium cations and the pyrophosphate anions.
Both the Na+ and the K+ cation have a similar biological function and therefore pyrophosphate salts of these types are considered to have a systemic toxicity profile. Differences arise in their local effects profile due to the increasing or decreasing acidity/alkalinity and buffering capacities of the substances. The pyrophosphate ion is the simplest form of a condensed phosphate group. The pyrophosphate can undergo ionisation with loss of H+ from each of the two –OH groups on each P and therefore can occur in the -1, -2 -3 or -4 states. The degree of ionisation is dependent upon the associated cations and the ambient pH (if in solution). Therefore, the above substances have a pyrophosphate anion that is likely to behave in a similar way.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
See read-across justification report under Section 13 ‘Assessment Reports’.

3. ANALOGUE APPROACH JUSTIFICATION
See read-across justification report under Section 13 ‘Assessment Reports’.

4. DATA MATRIX
See read-across justification report under Section 13 ‘Assessment Reports’.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

other: Code of Federal Regulations, section 1500.

Deviations:

not specified

Principles of method if other than guideline:

Twenty Wistar-derived rats were fasted for 24 h prior to administration of the test substance by oral gavage, doses ranged from 1.74 to 3.48 gm/kg bw . Each animal received the desired dosage in a single administration. The animals were observed for signs of toxicity and survival at 1, 3, 6, 24, 48 and 72 h and daily thereafter for a total of 14 days. Body weights were recorded on day 0, 7 and 14 of the study and all animals were autopsied and observed for gross pathological organ changes.

GLP compliance:

no

Remarks:

study predates GLP

Test type:

other: No data.

Limit test:

no

Species:

rat

Strain:

other: Wistar derived albinos

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Zartman Farms, Douglasville, Pa.
- Age at study initiation: no data
- Weight at study initiation: 200-300 grams
- Fasting period before study: 24 hours.
- Housing: Animals housed individually
- Diet (e.g. ad libitum): ad libitum. The animals were fed a standard laboratory diet of 'Purina Rat Chow'.
- Water (e.g. ad libitum): ad libitum.
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
no data

IN-LIFE DATES: From: no data

Route of administration:

oral: gavage

Vehicle:

not specified

Details on oral exposure:

No data.

Doses:

There were 5 dosing groups:
1.74, 2.17, 2.61, 3.04, 3.48 gm/kg bw

No. of animals per sex per dose:

Two animals per sex per dose.

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Necropsy of survivors performed: yes
- Frequency of other examinations performed:
Mortality - recorded at 1, 3, 6, and 24 hours and daily thereafter until terminal sacrifice at day 14.
Clinical signs - the animals were observed for adverse effects and drug induced toxicity at 1, 3, 6, and 24 hours and daily thereafter following adminsitration.
The animals were sacrificed on the 14th day and observed for gross pathological organ changes.

Statistics:

The 24- hour and 14-day LD50 determination was calculated in accordance with the method of Miller and Tainter, Exp. Bio. and Medicine, 57, pp261-264, 1944.

Preliminary study:

No data.

Sex:

male

Dose descriptor:

LD50

Effect level:

2 440 mg/kg bw

Based on:

not specified

Mortality:

See Table 1.

Clinical signs:

other: See Table 2. Rats administered between 1.74 and 3.28 gm/kg bw of the test material exhibited respiratory depression, ataxia, loss of righting reflex, ptosis, piloerection, tremors, decreased locomotor activity and dose-related mortality.

Gross pathology:

There were no outstanding gross pathological changes.

Other findings:

No data.

Table 1 - Survival for the acute oral toxicity study of MCTR-6 -75

Dose (gm/kg bw)	Hour						Day											Total
	1	3	6	24	48	72	4	5	6	7	8	9	10	11	12	13	14
1.74	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4
2.17	4	4	4	3	3	3	3	3	3	3	3	3	3	3	3	3	3	3
2.61	4	4	2	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
3.04	4	4	2	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
3.48	4	4	2	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

Table 2 - Observations made following adminstration of the test substance.

Dose (gm/kg bw)	Animal # / sex	Hour						Day
		1	3	6	24	48	72	4	5-14
1.74	1 /M	A,R,D,T,PT	Rr,R,PT,T	A,R,D,PT	D,P	D
	2 /M	A,R,D,T,PT	Rr,R,PT,T	A,R,D,PT	D,P
	3 /F	A,R,D,T,PT	Rr,R,PT,T	A,R,D,PT	D,P	D	D	D
	4 /F	A,R,D,T,PT	Rr,R,PT,T	A,R,D,PT	D,P	D

Dose (gm/kg bw)	Animal # / sex	Hour						Day
		1	3	6	24	48	72	4	5	6-14
2.17	1 /M	A,PT,R,D,T	Rr,T,R,PT	Rr,R,T,PT	PT,D,PT	D,P	D,P	D
	2 /M	A,PT,R,D,T	Rr,T,R,PT	Death	-	-	-	-	-	-
	3 /F	A,PT,R,D,T	Rr,R,PT	A,R,D,T,PT	D,A,R,P,PT	R,PT,D,P	PT,D,P	D,P	D
	4 /F	A,PT,R,D,T	Rr,T,R,PT	A,R,D,T,PT	PT,D,P	D,P	D,	D

Dose (gm/kg bw)	Animal # / sex	Hour						Day
		1	3	6	24	48	72	4	5	6-14
2.61	1 /M	Rr,R,T,PT	Death	-	-	-	-	-	-	-
	2 /M	Rr,R,T,PT	Rr,R,T,PT	A,R,D,P,PT	A,R,P,D,PT	D,P,PT	D,P,PT	D,P	D	-
	3 /F	Rr,R,T,PT	Rr,R,T,PT	Death	-	-	-	-	-	-
	4 /F	Rr,R,T,PT	Death	-	-	-	-	-	-	-

Dose (gm/kg bw)	Animal # / sex	Hour						Day
		1	3	6	24	48	72	4	5	6	7-14
3.04	1 /M	Rr,R,T,PT	Rr,R,T,PT	Rr,R,PT	A,R,D,P,PT	R,PT,D,P	PT,D,P	D,P	D	D	-
	2 /M	Rr,R,PT,T	Rr,R,PT,T	Death
	3 /F	Rr,R,PT,T	Death
	4 /F	Rr,R,PT,T	Death

Dose (gm/kg bw)	Animal # / sex	Hour						Day
		1	3	6	24	48	72	4	5	6	7-14
3.48	1 /M	Rr,R,T,PT	Death
	2 /M	Rr,R,PT,T	Rr,R,PT	Death
	3 /F	Rr,R,PT,T	Death
	4 /F	Rr,R,PT,T	Rr,R,PT	Death

A=Ataxia

D=Decreased locomotion

PT=Ptosis

R=Respiratory Depression

T=Tremors

Rr=Loss of righting reflex

Table 3 - Individual bodyweights

Dose (gm/kg bw)	Animal # / sex	Test day
		0	7	14
1.74	1 /M	210	225	275
	2 /M	210	235	280
	3 /F	200	210	215
	4 /F	205	210	225
2.17	1 /M	230	250	295
	2 /M	225	-	-
	3 /F	215	220	230
	4 /F	220	215	225
2.61	1 /M	200	-	-
	2 /M	210	220	245
	3 /F	200	-	-
	4 /F	200	-	-
3.04	1 /M	210	225	235
	2 /M	215	-	-
	3 /F	200	-	-
	4 /F	210	-	-
3.48	1 /M	220	-	-
	2 /M	215	-	-
	3 /F	210	-	-
	4 /F	210	-	-

Interpretation of results:

GHS criteria not met

Conclusions:

Male and female rats, when administered oral dose levels between 1.74 and 3.48 gm/kg bw of the test material exhibited respiratory depression, ataxia, loss of righting reflex, ptosis, piloerection, tremors, ecreased locomotor activity and dose-related mortality. Autopsies revealed no outstanding gross patholigical organ changes. The acute oral LD50 at 24 hours was 2.44 ± 0.19 gram/kg bw.
In accordance with Regulation (EC) No. 1272/2008 tetrapotassium triphosphate is not considered to be classified via the oral route.

Reference 8

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

no data

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
See read-across justification report under Section 13 ‘Assessment Reports’.
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In accordance with REACH Annex XI, Section 1.5, of Regulation (EC) No. 1907/2006 (REACH) the standard testing regime may be adapted in cases where a grouping or read-across approach has been applied.

The similarities may be based on:
(1) a common functional group
(2) the common precursors and/or the likelihood of common breakdown products via physical or biological processes, which result in structurally similar chemicals; or
(3) a constant pattern in the changing of the potency of the properties across the category

The source and target substances are both inorganic salts of a monovalent cation from Group 1A of the periodic table, sodium or potassium, and pyrophosphoric acid. Thus, they all share the sodium or potassium cation and the pyrophosphate anion as common functional groups.
All members of the group will ultimately dissociate into the common breakdown products of sodium / potassium cations and the pyrophosphate anions.
Both the Na+ and the K+ cation have a similar biological function and therefore pyrophosphate salts of these types are considered to have a systemic toxicity profile. Differences arise in their local effects profile due to the increasing or decreasing acidity/alkalinity and buffering capacities of the substances. The pyrophosphate ion is the simplest form of a condensed phosphate group. The pyrophosphate can undergo ionisation with loss of H+ from each of the two –OH groups on each P and therefore can occur in the -1, -2 -3 or -4 states. The degree of ionisation is dependent upon the associated cations and the ambient pH (if in solution). Therefore, the above substances have a pyrophosphate anion that is likely to behave in a similar way.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
See read-across justification report under Section 13 ‘Assessment Reports’.

3. ANALOGUE APPROACH JUSTIFICATION
See read-across justification report under Section 13 ‘Assessment Reports’.

4. DATA MATRIX
See read-across justification report under Section 13 ‘Assessment Reports’.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

no guideline followed

Principles of method if other than guideline:

The diluted compound was fed by stomach tube to Sprague-Dawley albino rats. After the approximate Minimal Lethal Dose was determined, groups of rats were fed at levels designed to blanket the toxicity range thereby supplying data for calculation of the LD50 according to the method of Bliss. Observations were made for toxic symptoms and the viscera of animals that succumbed were examined macroscopically.

GLP compliance:

no

Remarks:

study predates GLP

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

no data

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
- Concentration in vehicle: the test material was diluted to produce a 50.0% aqueous solution.
- Amount of vehicle (if gavage): no data
- Justification for choice of vehicle: no data
- Lot/batch no. (if required): not applicable
- Purity: not applicable

MAXIMUM DOSE VOLUME APPLIED: 5010 mg/kg bw

- Rationale for the selection of the starting dose: The minimum lethal dose was predetermined and used to provide a range of doses from which the LD50 could be calculated

Doses:

2510 mg/kg bw
3160 mg/kg bw
3980 mg/kg bw
5010 mg/kg bw

No. of animals per sex per dose:

21 animals grouped as follows:
2510 mg/kg bw - 3 female, 2 male
3160 mg/kg bw - 3 female, 3 male
3980 mg/kg bw - 2 female, 2 male
5010 mg/kg bw - 3 female, 2 male

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: no data
- Frequency of observations and weighing: no data
- Necropsy of survivors performed: yes
- Other examinations performed: observationf for toxic symptoms and the viscera of the animals that succumbed were examined macroscopically.

Statistics:

Calculation of the LD50 was performed from the data derived from the four dose groups accroding to a modified version of the method of Bliss.

Preliminary study:

no data

Sex:

male/female

Dose descriptor:

approximate LD50

Effect level:

3 160 mg/kg bw

Remarks on result:

other: The upper and lower limits of the LD50 were placed at 2685 to 3665 mg/kg bw

Mortality:

The deaths of the animals are recorded in the results table.
Survival time was several hours to four days with most deaths occuring overnight.

Clinical signs:

other: Toxic symptoms included weakness in a few hours followed by collapse and coma.

Gross pathology:

At autopsy there was renal and pulmonary congestion by macroscopic examination.

Other findings:

no data

The Oral LD50 of Tetrapotassium Pyrophosphate for Rats

sample fed as a 50.0% aqueous solution

Animal No. – Sex	Weight Gm.	Dose mg/kg	Fate
1 – female	175	2510	survived
2 – male	200	2510	survived
3 – female	185	2510	died
4 – female	190	2510	survived
5 – male	210	2510	survived
6 – male	200	3160	died
7 – male	195	3160	survived
8 – female	175	3160	died
9 – female	185	3160	died
10 – female	200	3160	survived
11 – male	180	3160	survived
12 – male	190	3980	died
13 – female	165	3980	died
14- female	180	3980	survived
15 – male	175	3980	died
16 – male	200	3980	died
17 – male	195	5010	died
18 – female	170	5010	died
19 – female	185	5010	died
20 – female	175	5010	died
21 – male	190	5010	died

Under the author's system of classification the compound was classed as slightly toxic by oral ingestions in rats.

Interpretation of results:

GHS criteria not met

Conclusions:

The LD50 was placed at 3160 mg/kg bw and the test material was classified, by the author, as slightly toxic by oral ingestions in rats.

In accordance with Regulation (EC) No. 1272/2008 (EU CLP) tetrapotassium pyrophosphate is not considered to be classified for acute oral toxicity.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

LD50 >2000 mg/kg bw
A weight of evidence is submitted; tests were performed on the regsitered substance and analogous substances.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

No data

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 81-3 (Acute inhalation toxicity)

Deviations:

yes

Remarks:

- minor deviations: the chamber and room humidity was slightly higher than recommended in the guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

- minor deviations: the chamber and room humidity was slightly higher than recommended in the guideline

Qualifier:

according to guideline

Guideline:

EU Method B.2 (Acute Toxicity (Inhalation))

Deviations:

yes

Remarks:

- minor deviations: the chamber and room humidity was slightly higher than recommended in the guideline

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Kingston, NY
- Age at study initiation: The actual age of the rats was not specified, only that they were young adults.
- Weight at study initiation (± SD): Males: 318 ± 11.4 g; Females: 249 ± 12.6 g
- Fasting period before study: No data
- Housing: Animals were housed individually in stainless steel suspended rat cages. Deosorb bedding was used in the litter pans.
- Diet: Purina Laboratory Rodent Chow 5001 available ad libitum
- Water: Tap water available ad libitum
- Acclimation period: Minimum of 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 - 23 °C (quoted in the study as 69 - 74 °F)
- Humidity (%): 42 - 77%
- Air changes (per hr): 14.2 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 h fluorescent light and 12 h dark cycle

Route of administration:

inhalation: dust

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: The Rochester type exposure chamber was made of stainless steel and glass and was operated dynamically. The calculated 99% equilibrium time for the chamber at a flow rate of 35.6 L per minute was 19.4 minutes (equivalent to 14.2 "air changes per hour").
- Exposure chamber volume: 150 L
- Method of holding animals in test chamber: The test animals were assigned to and housed in individual compartments of a wire mesh cage bank (all on the same horizontal level) during the exposure.
- Source and rate of air: Breathing grade compressed air was used and the total chamber air flow rate was 35.6 L/minute.
- Method of conditioning air: No data
- System of generating particulates/aerosols: The test material was generated using a BGI Wright Dust Feeder II. The test material was desiccated and packed into large dust cups. Breathing Grade compressed air was metered to the Wright dust feeder through teflon tubing by a Matheson® 605 rotameter with a metal float. Rotameter back pressure was controlled using a Matheson® 3104C regulator. The dust feeder back pressure was monitored using a Marshalltown® back pressure gauge. The test material was made airborne by the compressed air dispersing the material into the exposure chamber. The concentration of the test atmosphere was controlled by the delivery rate setting of the Wright dust feeder.
- Method of particle size determination: The samples were drawn through a Sierra 218 cascade impactor at 2.78 liters per minute. The aerodynamic particle size distribution was determined by gravimetric analysis of the amount of test material collected on the impactor stages and subsequent determination of the mass median aerodynamic diameter (MMAD), geometric standard deviation and other particle size parameters by logarithmic-probability plotting.
- Treatment of exhaust air: The chamber air was exhausted from the bottom of the chamber and passed through an orifice tube system which continuously monitored airflow and then through a commercial filter box. The filter box was connected to a line leading to additional filters and an exhaust fan on the roof. The exhaust operated at a flow rate of 35.6 liters per minute, creating a slight negative pressure in the chamber, which was considered to be the total chamber air flow rate. The entire exposure system and primary exhaust filter were contained in a fume hood.
- Temperature, humidity, pressure in air chamber: The mean temperature and relative humidity in the chamber were 22 °C (71 °F) and 66%, respectively. The pressure in the air chamber was not measured.


TEST ATMOSPHERE
- Brief description of analytical method used: The airborne concentration of the test material was determined gravimetrically.
- Samples taken from breathing zone: Yes - Chamber air samples were taken on glass fiber filters held in cassettes at approximately one hour intervals during the exposure to determine the airborne concentration of test material. The airborne concentration of the test material was determined gravimetrically by drawing a known amount of chamber air through the filter. The samples were taken from the center of the chamber directly over the animal exposure caging.
The difference between gravimetric and nominal concentration was attributed to sedimentation of larger particles and/or adhesion of the test material to surfaces in the exposure chamber.


VEHICLE
- Not applicable: The test material was administered as received and a vehicle was not used.


TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: The fraction of particles less than or equal to 1 µm in mass aerodynamic diameter, based on the log-probability graphs, ranged from 7.6 to 9.4%. The fraction of particles less than or equal to 10 µm in mass aerodynamic diameter, based on the log probability graphs, ranged from 72.3 to 76.1%. These results indicated the test material was respirable in size to the rat.
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): The MMADs ranged from 4.61 to 4.87 micrometers (µm) with geometric standard deviations ranging from 2.98 to 3.39. The MMAD represents the smallest size that could be achieved in this study. The material is hygroscopic causing the particles to agglomerate and/or adhere to surfaces inside the chamber. Several trials were initially performed with various generation schemes and the system which was ultimately chosen provided the best performance.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

Nominal concentration: 35.14 mg/L (maximum attainable concentration)
Gravimetric concentration: 0.58 ± 0.103 mg/L

No. of animals per sex per dose:

5 animals/sex

Control animals:

no

Details on study design:

- Duration of observation period following administration: 28 days
- Frequency of observations and weighing: Animals were observed for signs of toxicity and mortality every 15 mins during the first hour of exposure, hourly for the remainder of the exposure, upon removal from the chamber, at 1 h post-exposure, twice daily thereafter for 27 days and once on day 28. Individual body weights were recorded on days 0, 1, 2, 4, 7, 14, 21 and 28.
- Necropsy of survivors performed: Yes
- Other examinations performed: No data

Statistics:

No data

Preliminary study:

Not applicable

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 0.58 mg/L air (analytical)

Exp. duration:

4 h

Mortality:

See Table 1.
One female died on day 1 and one male died on day 14 post-exposure.

Clinical signs:

other: See Table 1. Clinical signs noted during the exposure included lacrimation, material on fur, oral discharge and squinting eyes. Incidence of clinical signs was highest at the removal from chamber observation. Signs gradually resolved during the study, how

Body weight:

See Table 2.
Most animals lost weight through day 4 of the study, then began to gain weight in a normal pattern. At termination all surviving animals exhibited increases in body weight over their day 0 values.

Gross pathology:

See table 3.
There were no gross internal lesions observed in any animal which survived to study termination. One male which died on day 14 had discoloured lungs with many light red nodules. This animal was also observed to have a corneal opacity in one eye.

Other findings:

No data

See attached file for Tables 1, 2 and 3.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this study, the test material caused mortality in one male and one female Sprague Dawley rat when administered for four hours at a mean, maximum attainable chamber concentration of 0.58 mg/L. Based on this, the LC50 for sodium acid pyrophosphate is considered to be greater than 0.58 mg/L.
This study is considered to be acceptable and to adequately satisfy both the guideline requirement and the regulatory requirement as a key study for this endpoint. In addition the study is considered to be acceptable for classification and labelling in accordance with Regulation (EC) No 1272/2008 (EU CLP) and as such sodium acid pyrophosphate is not considered to be acutely toxic via the inhalation route (EU CLP).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

LC50 > 3690 mg/m3
Key study is performed according to guideline and under GLP (Klimisch reliability 1).

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was performed between 12 May 2010 and 26 May 2010.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Deviations:

no

Principles of method if other than guideline:

The sequence of dosing may not always follow the Test Guideline as shown in the schematic diagram in attachment 1. It is Company Policy to minimisethe number of animals used on each study in accordance with UK Government Home Office guidelines.

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of Inspection: 15 September 2009 Date of signature: 26 November 2009

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Test Animals:
Animals: Rat, HsdRccHan: WIST

Rationale: Recognized by international guidelines as a recommended test system.

Breeder: Harlan Laboratories UK Limited, Oxon, UK.

Number of Animals per Group: 5 males and 5 females

Total number of Animals: 5 males and 5 females

Age when treated: At the start of the study the animals weighed at least 200g, and were eight to twelve weeks of age. The weight variation did not exceed ± 20% of the mean weight for each sex.

Identification: After an acclimatisation period of at least five days the animals were selected at random and given a number unique within the study by indelible ink-marking on the tail and a number written on a cage card.

Acclimatization: At least 5 days under laboratory conditions, after health examination. Only animals without any visible signs of illness were used for the study.

Environmental Conditions:
Conditions:
The temperature and relative humidity were within the range of 19 to 21 cC and 45 to 56% respectively. The rate of air exchange was at least fifteen changes per hour and the lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve hours darkness.

The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

Accommodation:
The animals were housed in suspended solid-floor polypropylene cages furnished with woodflakes. The animals were housed individually during the 24-hour exposure period and in groups of five, by sex, for the remainder of the study.

Diet:
Free access food (2014 Teklad Global Rodent diet supplied by Harlan Laboratories UK, Oxon, UK) was allowed throughout the study. The diet was routinely analysed and were considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study.

Water:
Free access to mains drinking water was allowed throughout the study. The drinking
water was routinely analysed and were considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study.

Type of coverage:

semiocclusive

Vehicle:

arachis oil

Details on dermal exposure:

On the day before treatment the back and flanks of each animal were clipped free of hair.

Using available information on the toxicity of the test material, a group of five male and five female rats was treated with the test material at a dose level of 2000 mg/kg.

The appropriate amount of test material, moistened with arachis oil, was applied as evenly as possible to an area of shorn skin (approximately 10% of the total body surface area). A piece of surgical gauze was placed over the treatment area and semi-occluded with a piece of self adhesive bandage. The animals were caged individually for the 24-Hour exposure period. Shortly after dosing the dressings were examined to ensure that they were securely in place.

Duration of exposure:

24 hours

Doses:

2000 mg /kg body weight

No. of animals per sex per dose:

5

Control animals:

not required

Details on study design:

After the 24-Hour contact period the bandage was carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with distilled water to remove any residual test material. The animals were returned to group housing for the remainder of the study period.

The animals were observed for deaths or overt signs of toxicity ½, 1, 2 and 4 hours after dosing and subsequently once daily for fourteen days.

After removal of the dressings and subsequently once daily for fourteen days, the test sites were examined for evidence of primary irritation and scored according to the following scale from Draize J H (1977) "Dermal and Eye Toxicity Tests" In: Principles and Procedures for Evaluating the Toxicity of Household Substances, National Academy of Sciences, Washington DC p.31:

EVALUATION OF SKIN REACTIONS
Erythema and Eschar Formation Value
No erythema 0
Very slight erythema (barely perceptible) 1
Well-defined erythema 2
Moderate to severe erythema 3
Severe erythema (beef redness) to slight eschar formation (injuries in depth) 4
Oedema Formation
No oedema 0
Very slight oedema (barely perceptible) 1
Slight oedema (edges of area well-defined by definite raising) 2
Moderate oedema (raised approximately 1 millimetre) 3
Severe oedema (raised more than 1 millimetre and extending beyond the area of exposure) 4

Any other skin reactions, if present were also recorded.

Individual bodyweights were recorded prior to application of the test material on Day 0 and on Days 7 and 14.

At the end of the study the animals were killed by cervical dislocation. All animals were subjected to gross necropsy. This consisted of an external examination and opening of the abdominal and thoracic cavities. The appearance of any macroscopic abnormalities was recorded. No tissues were retained.

Statistics:

No statistical analysis was performed.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: 95% confidence limits not reported.

Mortality:

No deaths occurred during the study.

Clinical signs:

other: No clinical signs were observed during the course of the study. There were no signs of dermal irritation.

Gross pathology:

No macroscopic findings were recorded at necropsy.

Other findings:

None.

Table1              Individual Clinical Observations and Mortality Data

Dose Level mg/kg	Animal Number and Sex	Effects Noted After Initiation of Exposure (Hours)				Effects Noted After Initiation of Exposure (Days)
		½	1	2	4	1	2	3	4	5	6	7	8	9	10	11	12	13	14
2000	1-0 Male	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	1-1 Male	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	1-2 Male	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	1-3 Male	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	1-4 Male	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-0 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-1 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-2 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-3 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-4 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

0= No signs of systemic toxicity

See attachment for Tables 2 - 4

Interpretation of results:

GHS criteria not met

Conclusions:

The acute dermal median lethal dose (LD50) of the test material in the Wistar strain rat was found to be greater than 2000 mg/kg bodyweight.
Disodium dihydrogenpyrophosphate is not considered to be classified according to Regulation (EC) No. 1272/2008 (EU CLP).

This study is considered to be reliable and acceptable for use as a key study.

Executive summary:

Introduction. The study was performed to assess the acute dermal toxicity of the test material in the Wistar strain rat. The method was designed to meet the requirements of the following

OECD Guidelines for the Testing of Chemicals No. 402 “Acute Dermal Toxicity” (adopted24 February 1987)

Method B3 Acute Toxicity (Dermal) of Commission Regulation (EC) No. 440/2008

Method. A group of ten animals (five males and five females) was given a single, 24-hour, semi‑occluded dermal application of the test material to intact skin at a dose level of 2000 mg/kg bodyweight. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

Mortality. There were no deaths.

Clinical Observations. There were no signs of systemic toxicity.

Dermal Irritation. There were no signs of dermal irritation.

Bodyweight. All animals showed expected gains in bodyweight over the study period.

Necropsy. No abnormalities were noted at necropsy.

Conclusion. The acute dermal median lethal dose (LD₅₀) of the test material in the Wistar strain rat was found to be greater than 2000 mg/kg bodyweight.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

LD50 >2,000 mg/kg bw
Key study is performed according to guideline and under GLP (Klimisch reliability 1).

Additional information

Acute oral toxicity:

A total of fourteen oral toxicity studies are available on sodium acid pyrophosphate (SAPP) and analogous substances. Five studies were performed on sodium acid pyrophosphate (SAPP), five on tetrapotassium pyrophosphate (TKPP) and four on tetrasodium pyrophosphate (TSPP) with reported LD50 values ranging between >1000 mg/kg bw and 3770 mg/kg bw.

 One study on tetrasodium pyrophosphate is a reliability 1. Two studies on tetrapotassium pyrophosphate are reliability two, one study on disodium dihydrogenpyrophosphate is considered unreliable (reliability three) and all other studies are reliability four.

 

All available tests will be used as part of the weight of evidence for this endpoint and to conclude on classification and labelling.

The study conducted by Bradshaw, 2010, on tetrasodium pyrophosphate is the only study conducted to a modern guideline and under the conditions of GLP. As the LD50 has been determined to be < 2000 mg/kg bw tetrasodium pyrophosphate is considered to be classified as acutely toxic via the oral route, category 4, in accordance with Regulation (EC) No. 1272/2008 (EU CLP).

The additional data provided on all substances suggests the LD50 for sodium and potassium pyrophosphates to lie around the 2000 mg/kg bw mark and therefore all the information on each substance will be taken into account in order to prevent precautionary over-classification for disodium dihydrogenpyrophosphate and tetrapotassium pyrophosphate.

Justification for classification or non-classification

Acute oral toxicity: The weight of evidence indicates that the oral LD₅₀is greater than the classification limit of 2000 mg/kg bw and therefore in accordance with Regulation (EC) No. 1272/2008 (EU CLP) no classification is proposed.

Acute inhalation toxicity: The LC₅₀for inhalation is >0.58 mg/L, the greatest attainable concentration and therefore in accordance with Regulation (EC) No. 1272/2008 (EU CLP) classification is not justified.

Acute dermal toxicity: The dermal LD50 of sodium acid pyrophosphates in the Wistar rat was estimated to be > 2000 mg/kg bw and is therefore not classified according to Regulation (EC) No. 1272/2008 (EU CLP).