Potassium carbonate

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Report date:

1984

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: FDA, Appraisal of the Safety of Chemicals in Food, Drugs and Cosmetics, 1959

Principles of method if other than guideline:

Draize Test

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Potassium carbonate

EC Number:

209-529-3

EC Name:

Potassium carbonate

Cas Number:

584-08-7

Molecular formula:

CH2O3.2K

IUPAC Name:

dipotassium carbonate

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: H. Fortkamp, 4540 Lengerich
- Age at study initiation: 11 -17 weeks, male
- Weight at study initiation: 2.57 - 2.85 kg
- Housing: individual in screen bottom cages
- Diet: ad libitum, Ssniff K, laboratory rabbit chow (Ssniff Versuchstier-Diäten GmbH, 4770 Soest/ Westfalen, Germany) ad libitum
- Water: tap water, ad libitum
- Acclimation period: 7 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 23 °C
- Humidity (%): 40 - 70 %
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12 hours dark/light cycle

Test system

Vehicle:

unchanged (no vehicle)

Controls:

other: The untreated eye served as control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 ml
- Concentration (if solution): instilled undiluted in the original state as delivered by the sponsor

Duration of treatment / exposure:

eyes were not rinsed.

Observation period (in vivo):

7 days

Number of animals or in vitro replicates:

6

Details on study design:

The animals were treated with the test article (as delivered by the sponsor), which was instilled into the conjunctival sac of the left eye after gently pulling the lower lid away from the eyeball. The lid was then gently held together for about one to two seconds, afterwards animals were returned to their cages.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): no

SCORING SYSTEM:
- as stipulated by Draize 1959 and guideline for acute eye irritation of US Interagency Regulatory Liaison Group (IRLG) Testing Standards and Guidelines Work Group (January 1981)

READINGS:
- 1 hour, 1, 2, 3, 4 and 7 days after instillation of test substance

TOOL USED TO ASSESS SCORE:
- 24 hours before treatment eyes were examined for lesions after application of fluorescein 0.15 %.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

animal: 1, 2, 6

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 7 d (=end of observation period)

Results 2

Irritation parameter:

cornea opacity score

Basis:

animal: 3, 4

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 7 d (= end of observation period)

Results 3

Irritation parameter:

cornea opacity score

Basis:

animal #5

Time point:

24/48/72 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 7 d

Results 4

Irritation parameter:

iris score

Basis:

animal: 1-6

Time point:

24/48/72 h

Score:

1.33

Max. score:

2

Reversibility:

not fully reversible within: 7 d (= end of observation period)

Remarks:

fully reversible for 50% of the animals

Results 5

Irritation parameter:

conjunctivae score

Basis:

animal: 1-6

Time point:

24/48/72 h

Score:

3

Max. score:

3

Reversibility:

not fully reversible within: 7 d (= end of observation period)

Results 6

Irritation parameter:

chemosis score

Basis:

animal: 1-6

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 d (= end of observation period)

Irritant / corrosive response data:

Moderate to serious effects on cornea, iris and conjunctiva were observed, but no clear proof that this is not reversible after 21 days was obtained.

Any other information on results incl. tables

Potash Eye Irritation mean values

Time point after treatment	Mean Values
	Cornea score opacity	Iris score	Conjunctiviae score
			redness	chemosis
1 hour	2,2	2	3	4
1day	2,2	2	3	4
2 days	2,2	2	3	4
3 days	2,2	2	3	4
4 days	1,8	1,7	3	3
7 days	1,8	0,5	2,3	1,8

Remark: no observations was made after 7 days

 

Scoring system

Score	Cornea score opacity	Iris score	Conjunctiviae score
			redness	chemosis
1	no opacity	normal	no redness	no swelling
2	single, slight opacity	morphologic changes	slight redness	slight swelling
3	diffuse opacity	tissue destruction	clear redness	clear swelling
4	distinct opacity	n.a.	strong redness	strong swelling

n.a. = not applicable

Mean Total Scores (MTS) according to Kay and Calandra were calculated and used for classification by the study authors:

1h: MTS = 56.3

1d: MTS = 60.5

2d: MTS = 65.5

3d: MTS = 70.5

4d: MTS = 57.8

7d: MTS = 49.8

Maximum Mean Total Score (MMTS) possible: 110)

Based on these mean scores, the test item was considered to be seriously irritating by the study authors.

Applicant's summary and conclusion

Interpretation of results:

Category 2 (irritating to eyes) based on GHS criteria

Conclusions:

Classification is based on effects on the cornea, iris and conjunctiva calculated as mean scores following grading at 24, 48 and 72 hours after instillation of the test material. The observation time did not extend beyond 7 days, therefore the reversibility of the effects could not be evaluated. As conclusion from this study, there are indications of severe eye irritation but no clear proof that this is not reversible over 21 days.

Executive summary:

In a primary eye irritation study according to FDA (Appraisal of the Safety of Chemicals in Food, Drugs and Cosmetics, 1959), the moistened test substance "potash-calc." was instilled into the conjunctival sac of 6 male New Zealand White rabbits. The eyes were not rinsed after substance application. Animals then were observed for 7 days. Irritation was scored by the method of Draize.

One hour after the application of the test item clear irritation of the eyes was observed. All animals showed conjunctival redness (mean score 3) and chemosis (mean score 4), accompanied by moderate secretion (score 2) and corneal opacity. In addition all animals developed an iritis. For all observed effects the mean scores decreased within the observation period of seven days. At day 7, all animals showed still slight to moderate conjunctival redness and slight to distinct chemosis, accompanied by secretion (score 1 or 3) in all but one animal. Corneal pannus formation was present in 2/6 animals. Five of the six animals had still an opacity of the cornea of different occurance (score 1 - 3). The iritis was completely reversible in 3/6 animals and had decreased in the other 3 animals to score 1 by day 7.

The observation time did not extend beyond 7 days, even though eye responses were still present at this time, since the test protocol followed did not demand a longer observation period at the time the study was performed. A decrease in severity of some effects was observed until study termination on day 7. No clear proof that the observed effects are not reversible after 21 days has been obtained.