Potassium carbonate

Skin irritation / corrosion

Administrative data

Endpoint:

skin 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:

Test substance applied to two sites per animal, on an abraded and an intact site, and held under occlusive dressing for 24 hours.

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

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: H. Fortkamp, 4540 Lengerich
- Age at study initiation: 11 -17 weeks, male
- Weight at study initiation: 2.58 - 2.94 kg
- Housing: individual in screen bottom cages
- Diet: ad libitum, Ssniff K, laboratory rabbit chow (Ssniff Versuchstier-Diäten GmbH, 4770 Soest/ Westfalen, Germany)
- Water: tap water, ad libitum
- Acclimation period: 6 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

Type of coverage:

occlusive

Preparation of test site:

other: shaved, one site abraded, one site intact

Vehicle:

physiological saline

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 500 mg test substance per application site (as delivered by the sponsor), moistened with physiological saline

Duration of treatment / exposure:

24 hours

Observation period:

72 hours

Number of animals:

6

Details on study design:

TEST SITE
- Area of exposure: 2.5 cm x 2.5 cm
- % coverage: trunk
- Type of wrap if used: occlusive

The dorsal area of the trunk of six rabbits was clipped one day before treatment with an electric clipper (Aesulap Favorita II).
Before start of treatment the right sites of each animal were scarified to induce a lesion of stratum corneum, without cause of bleeding or injury of the dermis.
A portion of 500 mg test substance was moistened with physiological saline and applied to each of the test sites, one abraded and one intact per animal and covered with a 2.5 x 2.5 cm gauze patch.
The gauze patch was secured with a self-adhesive, occlusive dressing. After 24 hours the coverings were removed and remaining test substance was wiped off with a disposal paper. Animals were examined for signs of erythema and edema one to two hours, and 48 hours after patch removal.

SCORING SYSTEM: as stipulated by Draize (1959)

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Remarks:

intact skin

Basis:

animal: 1-6

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

other: no reading at 48 h

Results 2

Irritation parameter:

edema score

Remarks:

intact skin

Basis:

animal: 1-6

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

other: no reading at 48 h

Irritant / corrosive response data:

Intact skin: sites were free of erythema and edema at both readings 24 and 72 hours after substance application (= 1 and 48 hour(s) after patch removal).
Abraded skin: a dark brown discoloration with moderate red edges (score 4) was observed at the 24 and 72 hours readings (= 1 and 48 hour(s) after patch removal) in all animals. These findings were interpreted by the study authors as necroses, and were accompanied by slight edema (score 2) at the 24 hours reading.

Any other information on results incl. tables

Irritation parameter results

Irritation parameter	Basis	Mean score		Remarks
		24 hr	72 hr
edema	animal: #1, #2, #3, #4, #5, #6	0	0	intact skin
erythema	animal: #1, #2, #3, #4, #5, #6	0	0	intact skin
edema	animal: #1, #2, #3, #4, #5, #6	2	0	abraded skin
erythema	animal: #1, #2, #3, #4, #5, #6	4	4	abraded skin

Intact skin: all readings were 0.

Abraded skin: 24 hours reading (= 1 hour after patch removal): erythema Score 4 in 6/6 animals; edema score 2 in 6/6 animals

72 hours reading (= 48 hours after patch removal): erythema Score 4 in 6/6 animals; edema score 0 in 6/6 animals

Average skin irritation index (Primary Dermal Irritation Index (PDII), maximal possible index of 8) calculated by the study authors: 2.5.

Effects on intact and abraded skin were included in the index calculation.

Based on this Index the test item was considered to be a moderate skin irritant by the study authors.

Scheme for interpretation of results used by the study authors:

Primary Skin Irritation Score (PDII)

0 : non irritant

> 0.- 2: mild irritant

> 2 - 5: moderate irritant

> 5: severe irritant

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Classification is based on erythema/eschar and oedema of intact skin calculated as mean scores following grading at 1 and 48 hour(s) after removal of the test material, in consideration of reversibility.
According to CLP, EU GHS (Regulation (EC) No 1272/2008) "potash-calc." is classified as non skin irritant.

Executive summary:

In a primary dermal irritation study according to FDA, Appraisal of the Safety of Chemicals in Food, Drugs and Cosmetics, 1959, six New Zealand White rabbits were dermally exposed to 500 mg of test substance “potash-calc.” per test site. The substance was administered for 24 hours to abraded and intact shaved body surface areas of 2.5 cm² each under occlusive conditions. Animals then were observed for further 48 hours. Irritation was scored by the method stipulated by Draize 1959 one to two hours, and 48 hours after patch removal (= 24 and 72 hours readings).

The intact skin sites were free of erythema and edema at both readings 24 and 72 hours after substance application.

According to the skin irritation/corrosion test guidelines EU Method B.4 and OECD TG 404 stipulated in COUNCIL REGULATION (EC) No 440/2008, only intact skin should be treated. Therefore, reactions of abraded skin are not included in the classification given above.

No classification for acute dermal irritation/corrosion is justified for "potash-calc." according to the following regulations:

• EU-GHS, Regulation (EC) No 1272/2008 (CLP)

• OECD GHS, (2nd rev. edition, UN, 2007)