Dipotassium oxide

Endpoint summary

Description of key information

When Potassium oxide is hydrated is produced Potassium hydroxide. Therefore, the health effects of Potassium hydroxide need to be considered in the assessment of Potassium oxide.
-The acute eye irritation study (Johnson, 1975) indicates that Potassium oxide (the result was read across from Potassium hydroxide) is corrosive to eye at concentrations of 5 % according to OECD 405 guidelines. 
Several concentrations of Potassium hydroxide were tested by a Draize test on rabbits by instilling 0.1 ml, rinsing after 5 minutes or 24 hours of exposure and examining with the aid of fluorescein at 1, 24, 48 and 72 hours, 7 days, and eventually 14-21 days. 
The results were as follows:
5%/5 min.: extremely irritant and corrosive 
1%/5 min.: irritant 
0.5%/24 hr: marginal 
0.1%/24 hr: no ocular reactions in the eye
Result: corrosive
Result: corrosive to eye at concentrations of 5% .
-The results of the study (Nixon GA et al.. 1975) indicate that Potassium oxide (the result was read across from Potassium hydroxide) is corrosive to skin at concentrations of 10% according to OECD 404 guidelines. 
Solid Potassium hydroxide is corrosive. Depending on the concentration, solutions of Potassium hydroxide are non-irritating, irritating or corrosive and they cause direct local effects on the skin and eyes. Systemic effects are not to be expected. Solutions with concentrations higher than 2% are corrosive, while concentrations of about 0.5 to about 2.0 % are irritating.
Result: corrosive to skin at concentrations of 10%
 
-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 and therefore Respiratory irritation is not expected
Result: not respiratory irritation

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

other: Published data

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

When Potassium oxide is hydrated is produced Potassium hydroxide. Therefore, the health effects of Potassium hydroxide need to be considered in the assessment of Potassium oxide According to the SIDS document for potassium hydroxide (30 January 2002), a Klimisch score of 2 was assigned since study is well documented, meets generally accepted scientific principles and is acceptable for assessment.

Qualifier:

according to guideline

Guideline:

other: revised Federal Hazardous Substances Act of FDA, Edwards 1972

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

scoring system not consistent with OECD guideline; study not stopped when corrosive activity observed; initial corrosivity patch testing not conducted

Principles of method if other than guideline:

revised FHSA: 4 h exposure in stead of 24h exposure

GLP compliance:

not specified

Species:

rabbit

Strain:

not specified

Details on test animals or test system and environmental conditions:

no data

Type of coverage:

occlusive

Preparation of test site:

other: abraded and intact skin

Vehicle:

unchanged (no vehicle)

Controls:

yes

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 ml
- Concentration (if solution): 10%

Duration of treatment / exposure:

4 h

Observation period:

48 hr, evaluation after 4, 24 and 48 hr.

Number of animals:

6

Details on study design:

TEST SITE
- Area of exposure: 4 sites/rabbit

SCORING SYSTEM: according to the descriptive scales in the proposed revision of the test procedure (FHSA, FDA, 1972)
Irritancy judgement is adopted from Draize (1959)
Primary Irritation Indices were calculated
PII= 0-0.4 is classified as "negligible"
PII=0.5-1.9 is classified as "slight"
PII= 2.0-4.9 is classified as "moderate"
PII= 5.0-8.0 is classified as "severe" = tissue destruction or irreversible change = "corrosive"

Irritation parameter:

other: FDA (USA) Federal Hazardous Substances Act, 1972 scoring system

Basis:

mean

Time point:

other: 4 hr

Score:

> 6.9

Max. score:

9

Remarks on result:

other: intact >6.9; abraded >7.0

Irritant / corrosive response data:

Tissue destruction: intact 6/6; abraded 6/6
irritancy judgement: KOH 10% = corrosive

Interpretation of results:

other: corrosive

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

Potassium hydroxide caused severe tissue destruction in all test animals.
KOH 10% is corrosive
When Potassium oxide is hydrated is produced Potassium hydroxide. Therefore, the health effects of Potassium hydroxide need to be considered in the assessment of Potassium oxide

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

other: Published data

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

When Potassium oxide is hydrated is produced Potassium hydroxide. Therefore, the health effects of Potassium hydroxide need to be considered in the assessment of Potassium oxide According to the SIDS document for potassium hydroxide (30 January 2002), a Klimisch score of 2 was assigned since study is well documented, meets generally accepted scientific principles and is acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

yes

Remarks:

grading of severity of the eye irritation was performed by a modification of the Draize method (1944)

Principles of method if other than guideline:

grading of severity of the eye irritation was performed by a modification of the Draize method (1944)

GLP compliance:

no

Species:

rabbit

Strain:

other: Albino

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- albino rabbits
- Weight at study initiation: 2-3 kg

Vehicle:

water

Controls:

yes

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 ml
- Concentration (if solution): 0.1, 0.5, 1.0 and 5.0%

Duration of treatment / exposure:

5 min or 24h

Observation period (in vivo):

1, 24, 48 and 72 hr and 7 days
if any injury persisted : 14 and 21 days

Number of animals or in vitro replicates:

10
KOH (5%) : 1 animal (5min)
KOH (1%): 3 animals (24h)
KOH (0.5%): 3 animals (24h)
KOH (0.1%): 3 animals (24h)

Details on study design:

TOOL USED TO ASSESS SCORE: fluorescein
REMOVAL OF TEST SUBSTANCE
- Washing (if done): 300 mL distilled water during 2 min
- Time after start of exposure: 5min or 24h

SCORING SYSTEM: modified Draize method: based upon the presence and the degree of ulceration or opacity of the cornea and iris and erythema, chemosis and ulceration or necrosis of the conjunctival mucosa

TOOL USED TO ASSESS SCORE: fluorescein

Irritation parameter:

overall irritation score

Basis:

animal #1

Time point:

other: 5 min

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

other: KOH 5%: extremely irritant and corrosive

Irritation parameter:

overall irritation score

Basis:

animal: 2-4

Time point:

other: 5 min

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

other: KOH 1% : irritant

Irritation parameter:

overall irritation score

Basis:

animal: 2-4

Time point:

other: 24h

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

other: KOH 1%: irritant

Irritant / corrosive response data:

KOH 5%/5 min.: extremely irritant and corrosive (1 rabbit)
KOH 1%/5 min.: irritant (3 rabbits);
KOH 1%/24 hr: irritant (3 rabbits);
KOH 0.5%/24 hr: marginal (3 rabbits);
KOH 0.1%/24 hr: negative (3 rabbits).
Result: KOH 5% = corrosive

Quantitative details are reported in: Johnson et al (1972) Acute toxicity studies of cesium and rubidium compounds. Nat Inst Occupational Safety Health Tech Rep 74

Interpretation of results:

other: corrosive

Remarks:

KOH 5% Criteria used for interpretation of results: EU

Conclusions:

KOH 5%/5 min.: extremely irritant and corrosive
KOH 1%/5 min.: irritant
KOH 0.5%/24 hr: marginal
KOH 0.1%/24 hr: no ocular reactions in the eye
Result: corrosive

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

When Potassium oxide is hydrated is produced Potassium hydroxide. Therefore, the health effects of Potassium hydroxide need to be considered in the assessment of Potassium oxide.

Eye irritation

-The acute eye irritation study(Johnson, 1975)indicates that Potassium oxide (the result was read across from Potassium hydroxide) is corrosive to eye at concentrations of 5 % according to OECD 405 guidelines.

Several concentrations ofPotassium hydroxidewere tested by a Draize test on rabbits by instilling 0.1 ml, rinsing after 5 minutes or 24 hours of exposure and examining with the aid of fluorescein at 1, 24, 48 and 72 hours, 7 days, and eventually 14-21 days.

 

The results were as follows:

5%/5 min.: extremely irritant and corrosive

1%/5 min.: irritant

0.5%/24 hr: marginal

0.1%/24 hr: no ocular reactions in the eye

Result: corrosive

 

Result: corrosive to eye at concentrations of 5% .

 

 Skin irritation

-The results of the study (Nixon GA et al.. 1975) indicate that Potassium oxide (the result was read across from Potassium hydroxide) is corrosive to skin at concentrations of 10% according to OECD 404 guidelines.

 

Solid Potassium hydroxide is corrosive. Depending on the concentration, solutions of Potassium hydroxide are non-irritating, irritating or corrosive and they cause direct local effects on the skin and eyes. Systemic effects are not to be expected. Solutions with concentrations higher than 2% are corrosive, while concentrations of about 0.5 to about 2.0 % are irritating.

 

Result: corrosive to skin at concentrations of 10%

 

Respiratory irritation.

-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 and therefore Respiratory irritation is not expected

Result: not respiratory irritation

 

 

 

 

 

Effects on skin irritation/corrosion: corrosive

Effects on eye irritation: corrosive

Justification for classification or non-classification

Based on the hazard assessment of Potassium oxide /Dipotassium 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” andaccording to the criteria described in Directive 67/548 and in the CLP Regulation:

 

Directive 67/548

Skin Corrosivity C R35 Causes severe burns R34 Causes burns Skin Irritation Xi R38 Irritating to skin R43 May cause sensitization by skin contact Eye Irritation (Ocular Lesions) Xi R36 Irritating to eyes R37 irritating to respiratory system R41 Risk of serious damage to eyes

CLP

Skin Corrosivity  H314 Skin Corr 1A Causes severe skin burns and eye damage H314 Skin Corr 1B Causes severe skin burns and eye damage Skin Irritation  H315 Skin Irrit. 2 Causes skin irritation H317 Skin Sens. 1 May cause an allergic skin reaction Eye Irritation (Ocular Lesions) Xi H319 Eye Irrit. 2 Causes serious eye irritation H318 Eye Dam. 1 Causes serious eye damage H335 STOT SE 3 May cause respiratory irritation

 

It is concluded that the substance Potassium oxide/Dipotassium oxide meet the criteria to be classified for human health hazards for Dermal-local effect:R35 Causes severe burns,H314 Skin Corr 1B Causes severe skin burns and eye damage

 

It is concluded that the substance Potassium oxide/Dipotassium oxide meet the criteria to be classified for human health hazards for Dermal-local effect R41 Risk of serious damage to eyes,  H318 Eye Dam. 1 Causes serious eye damage.

It is concluded that the substance Potassium oxide/Dipotassium oxide does not meet the criteria to be classified for human health hazards for respiratory irritation