Dipotassium oxide

Endpoint summary

Description of key information

- Acute oral toxicity: The acute oral LD50 in male/female rats is >2000 mg/kg bw. All animals appeared active and healthy throughout the study period. No signs of toxicity were observed.
This show that Potassium oxide (the result was read across from Potassium Sodium Nitrate) is not toxic for acute Oral toxicity and Potassium oxide was not classified according to EU or GHS criteria.
-Acute Dermal Toxicity: An LD50 value of >5000 mg/kg was obtained for Potassium oxide (the result was read across from Potassium Nitrate). The dermal LD50 in male and female rats is >5000 mg/kg.
Alternatively and more conveniently Potassium oxide is synthesized by heating potassium nitrate with metallic potassium.
Therefore, the health effects of potassium nitrate need to be considered in the assessment of Potassium oxide.
Potassium oxide is not likely to be absorbed through the skin because of the low octanol-water partition coefficient of the substance. A reliable QSAR method predicts a value for the partition co-efficient (logKow) of -5.08  for this substance.
This show that Potassium oxide is not toxic for acute Dermal toxicity. Potassium oxide was not classified according to EU or GHS criteria
-Acute inhalation toxicity: Dust formation is unlikely because of the hygroscopic properties. Furthermore Potassium oxide has a negligible vapour pressure and therefore dust and vapour exposure are not expected.
Potassium oxide was not classified according to EU or GHS criteria.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

other: Published data

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Justification for type of information:

Well performed study, according to OECD test guideline and compliant with GLP. Alternatively and more conveniently Potassium oxide is synthesized by heating potassium nitrate with metallic potassium: 2 KNO3 + 10 K → 6 K2O + N2 Therefore, the health effects of potassium nitrate need to be considered in the assessment of Potassium oxide

Qualifier:

according to guideline

Guideline:

OECD Guideline 425 (Acute Oral Toxicity: Up-and-Down Procedure)

GLP compliance:

yes

Test type:

up-and-down procedure

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 60%
DOSAGE PREPARATION:
Prior to use, the test substance was ground in a coffee mill and administered by gavage as a 60% w/w suspension in distilled water (preliminary solubility testing indicated that suspensions in excess of 60% were too viscous to be administered properly).

Doses:

2000 mg/kg b.w.

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

All animals were observed for mortality, signs of gross toxicity, and behavioral changes at least once daily for 14 days after dosing. Bodyweights were recorded prior to administration and again on days 7 and 14 (termination) after dosing. Necropsies were performed on all animals at terminal sacrifice.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

All animals survived

Clinical signs:

other: All animals gained weight

Gross pathology:

No signs of toxicity were observed.

Interpretation of results:

other: not classified

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

Acute Oral Toxicity: An LD50 value of >2000 mg/kg was obtained.
LD50 > 2000 mg/kg bw
Alternatively and more conveniently Potassium oxide is synthesized by heating potassium nitrate with metallic potassium:
2 KNO3 + 10 K → 6 K2O + N2
Therefore, the health effects of potassium nitrate need to be considered in the assessment of Potassium oxide

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Data waiving:

other justification

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

86.96 mg/m³ air

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

other: Published data

Adequacy of study:

key study

Study period:

October 19 - November 2, 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Justification for type of information:

According to OECD 402 and GLP procedures. Alternatively and more conveniently Potassium oxide is synthesized by heating potassium nitrate with metallic potassium: 2 KNO3 + 10 K → 6 K2O + N2 Therefore, the health effects of potassium nitrate need to be considered in the assessment of Potassium oxide

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Principles of method if other than guideline:

limit dose of 5,000 mg/kg tested

GLP compliance:

yes

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: Received from Ace Animals, Inc., Boyertown, PA on October 10, 2000
- Age at study initiation: Young adult (8-9 weeks)
- Weight at study initiation: males 218-246 grams and females 194-215 grams at experimental start
- Fasting period before study:
- Housing: The animals were singly housed in suspended stainless steel caging with mesh
floors which conform to the size recommendations in the most recent Guide for the
Care and Use of Laboratory Animals DHEW (NIH). Litter paper was placed beneath
the cage and was changed at least three times per week.
- Diet (e.g. ad libitum): Purina Rodent Chow #5012
- Water (e.g. ad libitum): Filtered tap water was supplied ad libitum by an automatic water dispensing
system.
- Acclimation period: 9 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17-21C
- Humidity (%):
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light): 12 hour light/dark cycle

Type of coverage:

occlusive

Vehicle:

other: moistened with water

Details on dermal exposure:

TEST SITE
- Area of exposure: dose area of approximately 2 inches x 3 inches
- % coverage: approximately 10% of the body surface

REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes, with water
- Time after start of exposure: 24 h

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): (conc. 85%)Five thousand mg/kg of bodyweight of the
test substance (6.25 g/kg of test mixture)
- Constant volume or concentration used: yes
- For solids, paste formed: yes

Duration of exposure:

24 hours

Doses:

(conc. 85%) Five thousand mg/kg of bodyweight of the test substance (6.25 g/kg of test mixture)

No. of animals per sex per dose:

5 males and 5 females

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days (or other?) 14 days
- Frequency of observations and weighing:
- Necropsy of survivors performed: yes/no Yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other:
The animals were observed for mortality, signs of gross toxicity, and behavioral changes at 1 and 5
hours after application and at least once daily thereafter for 14 days. Observations included gross
evaluation of skin and fur, eyes and mucous membranes, respiratory, circulatory, autonomic and central
nervous systems, somatomotor activity and behavior pattern. Particular attention was directed to
observation of tremors, convulsions, salivation, diarrhea and coma.

Gross necropsies were performed on all animals. Tissues and organs of the thoracic and abdominal cavities were examined.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

test mat.

Mortality:

all animals survived

Clinical signs:

other: all animals appeared active and healthy

Gross pathology:

Gross pathology: All animals survived, gained weight and appeared active and healthy. There were no signs of gross toxicity, adverse pharmacologic effects or abnormal behavior. No gross abnormalities were noted for the animals necropsied at the conclusion of the 14-day observation period.

Interpretation of results:

other: not classified

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

Acute Dermal Toxicity: An LD50 value of >5000 mg/kg was obtained. The dermal LD50 in male and female rats is >5000 mg/kg.
Alternatively and more conveniently Potassium oxide is synthesized by heating potassium nitrate with metallic potassium:
2 KNO3 + 10 K → 6 K2O + N2
Therefore, the health effects of potassium nitrate need to be considered in the assessment of Potassium oxide

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Additional information

Acute oral toxicity:

 

The acute oral LD50 in male/female rats is >2000 mg/kg bw. All animals appeared active and healthy throughout the study period. No signs of toxicity were observed.

This show that Potassium oxide (the result was read across from Potassium Sodium Nitrate) is not toxic for acute Oral toxicity.

 

In an acute oral toxicity study (Boyd 1969, UNEP 2003) female Wistar rats received 0, 2100, 2400, 2700, 3300, 3600, 3900 mg/kg bw potassium chloride dissolved in water. The LD50 value has been determined 3020 mg/kg bw. Clinical signs of intoxication in animals that died included convulsions followed by exhaustion and respiratory failure Autopsy revealed signs of irritant gastro-enterisis and necrosis appeared in the renal tubular epithelium. Animals that survived had convulsive movements diarrheam or sonstipation loss of appetite increase thirst and urine excretion and fever, Measurements of clinical sigh´ns were within the normal range within 2 -3 days and organ weights and water levels returned to normal limits in survivors at 2 weeks after administration of potassium chloride .

 

Conclusion:

Potassium oxide was not classified according to EU or GHS criteria.

 

Acute Dermal Toxicity:

 An LD50 value of >5000 mg/kg was obtained for Potassium oxide (the result was read across from Potassium Nitrate). The dermal LD50 in male and female rats is >5000 mg/kg.

Alternatively and more conveniently Potassium oxide is synthesized by heating potassium nitrate with metallic potassium.

Therefore, the health effects of potassium nitrate need to be considered in the assessment of Potassium oxide.

Potassium oxide is not likely to be absorbed through the skin because of the low octanol-water partition coefficient of the substance. A reliable QSAR method predicts a value for the partition co-efficient (logKow) of -5.08 for this substance.

 

Conclusion:

Potassium oxide is not toxic for acute Dermal toxicity. Potassium oxide was not classified according to EU or GHS criteria

 

 

-Acute inhalation toxicity:

 

Dust formation is unlikely because of the hygroscopic properties. Furthermore Potassium oxide has a negligible vapour pressure and therefore dust and vapour exposure are not expected.

 

Conclusion:

Potassium oxide was not classified according to EU or GHS criteria.

 

 

Inhalation effects:

There are no Acute inhalation studies available.

The oral dose for the rat is converted to the corresponding air concentration using a standard breathing volume for the rat (1.15m3/kg for 24 hours exposure. The resulting air concentration needs to be additionally corrected for 24 hlight activity (20 m3), assuming 100 % absorption for both routes.

LD50 rat             2000 mg/kg bw/day

÷1.15m3/kgbw

÷20m3/rat

 

LC50rat    86.96mg/m3

 

 

Justification for classification or non-classification

Based on the hazard assessment of Potassium oxide in section 2.1 and 2.2. in IUCLID 5.4., available data for the substance and following the “Guidance on Information Requirement and Chemical Safety Assessment R.8. Characterisation of dose [concentration]- response for human health”, according to the EU’s list of dangerous substances (OJEC No L200/130.7.99)and according to the criteria described in Directive 67/548 and in the CLP Regulation:

Directive 67/548

Very Toxic (T+) R28: Very toxic if swallowed R27: Very toxic in contact with skin R26: Very toxic by inhalation R39/26 R39/27 R39/28: Dangerous of very serious irreversible effects Toxic (T):  R25: Toxic if swallowed R24: Toxic in contact with skin R23: Toxic by inhalation R39/23 R39/24 R39/25: Danger of very serious irreversible effects Harmful (Xn): R22: Harmful if swallowed R21: Harmful in contact with skin R20: Harmful by inhalation R65: Harmful may cause lung damage if swallowed R21/22 Harmful; Harmful in contact with skin and if swallowed. R68/20 R68/21 R68/22: Possible risk of irreversible effects Other toxicological properties R67: Vapours may cause drowsiness and dizziness

CLP

H300 Acute Tox. 2 Fatal if swallowed H310 Acute Tox. 1 Fatal in contact with skin H330 Acute Tox. 2 Fatal if inhaled H370 STOT SE 1 H301 Acute Tox. 3 Toxic if swallowed H311 Acute Tox. 3 Toxic in contact with skin H331 Acute Tox. 3 Toxic if inhaled H370 STOT SE 1 H302 Acute Tox. 4 Harmful if swallowed H312 Acute Tox. 4 Harmful in contact with skin H332 Acute Tox. 4 Harmful if inhaled H304 Asp. Tox. 1 H371 STOT SE 2 (May cause damage to organs (or state all organsaffected if known) (state route of exposure if it is conclusively proventhat no other routes of exposure cause the hazard) Other toxicological properties H336 STOT SE 3 May cause drowsiness or dizziness

It is concluded that the substance Potassium oxide does not meet the criteria to be classified for human health hazards for acute oral effects