Sodium 4-hydroxybenzenesulphonate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

None

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2004

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2500 (Acute Dermal Irritation)

Deviations:

not specified

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Sodium 4-hydroxybenzenesulphonate

EC Number:

212-550-0

EC Name:

Sodium 4-hydroxybenzenesulphonate

Cas Number:

825-90-1

Molecular formula:

C6H6O4S.Na

IUPAC Name:

sodium 4-hydroxybenzenesulphonate

Test material form:

solid

Specific details on test material used for the study:

- Lot no. G9439
- Purchased from: ABCR GmbH & Co., Germany

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

Male and female New Zealand white rabbits (Oryctolagus cuniculus) were purchased from the Millbrook Rabbit Breeding Labs in Amherst, MA. These animals were chosen for study based upon their historical use in dermal safety studies and upon OPPTS guidelines (USEPA 1998). Healthy rabbits at least 10 weeks old (adult) were purchased, with weights ranging be¬tween 2.03 and 2.24 kg (weighed to the nearest 10 g). Animals were randomized when received from the vendor by the assign¬ment of a unique identification number. The animals used in the studies had not been used in previous experiments and were observed to be free from any skin irritation, trauma, or adverse clinical signs prior to initiation of the studies. The numbers of animals used in these studies were based upon OPPTS guide-lines (USEPA 1998). An untreated patch of dorsal skin on each animal served as its control.
Rabbits were housed individually in suspended stainless steel cages with noncontact hardwood chips as bedding. Laboratory room temperature was 68°F (±5°F), and animal room relative humidity was between 30% and 70% with 10 to 15 air exchanges per hour. A 12-hour light/dark cycle of full spectrum fluorescent lights was maintained. The laboratory and animal rooms were maintained as limited-access facilities. Animals were fed TEK 8630 Rabbit Diet (from Harlan Teklad, Madison, WI) and tap water, ad libitum.

Test system

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

other: a distilled water vehicle (United States Pharma¬copeia [USP])

Controls:

no

Amount / concentration applied:

Two groups: 5000 or 2000 mg/L; 0.5 ml of each concentration for each dose cohort was applied to a small area of skin (approximately 6 cm2)

Duration of treatment / exposure:

4 hours

Observation period:

72 hours

Number of animals:

3 per group

Details on study design:

A total of three animals were treated for each applied concentration, two doses were applied: 5000 and 2000 mg/L. All of the tests used a distilled water vehicle (United States Pharmacopeia [USP]) with application volumes of 0.5 ml of each stock dosing solution. Each dose level was tested in a separate group of animals. Each dose of test compound (0.5 ml of each concentration for each dose cohort) was applied to a small area of skin (approximately 6 cm²) and covered with four layers of gauze patch held in place with nonirritating tape. Because the sulfonate compounds were in liquid form, they were applied to the gauze before application to the skin. The patch was loosely held in contact with the skin using a semiocclusive dressing for the exposure period of 4 hours. Access by the animal to the patch was prevented, eliminating the potential for ingestion or inhalation of the test substance. At the end of the 4-hour exposure period, the patches were removed and the skin wiped to remove any test substance still remaining. Animals were observed for signs of erythema and edema at 1, 24, 48, and 72 hours after patch removal. Observations of erythema or edema were scored according to the Draize Scale for Scoring Skin Reactions (USEPA 1998). This scale assesses irritation as follows:
0, no erythema or edema;
1, very slight erythema and/or edema (barely perceptible);
2, well-defined erythema and/or slight edema;
3, moderate to severe erythema or moderate edema, and
4, severe erythema and/or edema.
Animals were weighed before exposure and at the end of the exposure period (day 3) and observed daily for the incidence of any clinical signs of toxicity (other than erythema and edema). Observations for these clinical signs included but were not limited to rigor, changes in respiration pattern, and convulsion.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0.67

Max. score:

4

Reversibility:

fully reversible within: 72

Results 2

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 24 h

Results 3

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 72 h

Results 4

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

other: no edema observed during the study

Irritant / corrosive response data:

At 5000 mg/L, well-defined erythema (Draize score of 2) was observed in one of the three test animals 1 hour after removal of the test substance. At the 24- and 48-hour observation points, very slight irritation (Draize Score of 1) was seen in this animal. By 72 hours, the irritation had been reversed. In the other two test animals, very slight irritation (Draize Score of 1) was observed 1 hour after removal of the test substance. By 24 hours, the irritation was reversed in these two animals. No erythema or edema was observed in any test animals at 2000 mg/L. Control skin showed no signs of irritation.

Other effects:

None

Any other information on results incl. tables

None

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Sodium-4-hydroxybenzenesulfonate is not a skin irritant.

Executive summary:

The skin irritation potential of Sodium-4-hydroxybenzenesulfonate was evaluated in a study conducted according to OPPTS, USEPA, Health Effects Test Guidelines: OPPTS 870.2500, Acute Dermal Irritation, 1998 using New Zealand white rabbits. A total of three animals were treated for each applied concentration, two doses were applied: 5000 and 2000 mg/L. Each dose of test compound (0.5 ml of each concentration for each dose cohort) was applied to a small area of skin (approximately 6 cm²) and covered with four layers of gauze patch held in place with nonirritating tape. The patch was loosely held in contact with the skin using a semiocclusive dressing for the exposure period of 4 hours. Animals were observed for signs of erythema and edema at 1, 24, 48, and 72 hours after patch removal. Observations of erythema or edema were scored according to the Draize Scale for Scoring Skin Reactions (USEPA 1998).

At 5000 mg/L, well-defined erythema (Draize score of 2) was observed in one of the three test animals 1 hour after removal of the test substance. At the 24- and 48-hour observation points, very slight irritation (Draize Score of 1) was seen in this animal. By 72 hours, the irritation had been reversed. In the other two test animals, very slight irritation (Draize Score of 1) was observed 1 hour after removal of the test substance. By 24 hours, the irritation was reversed in these two animals. No erythema or edema was observed in any test animals at 2000 mg/L. Control skin showed no signs of irritation. Based on these findings, it is clear that the exposure of Sodium-4-hydroxybenzenesulfonate on rabbit skin does not cause irritation that qualifies for the classification under the provisions of Regulation EC No. 1272/2008 (CLP). Hence, Sodium-4-hydroxybenzenesulfonate is not a skin irritant.