resorcinol; 1,3-benzenediol

Endpoint summary

Description of key information

Resorcinol is slightly too severely irritating to the skin and severely irritating to eyes when administered in a dissolved and semi-solid state. No information was available on respiratory irritation, but based on irritation effects observed on the skin and eyes of experimental animals it is likely that respiratory irritation will also be observed.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

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:

other: Guideline Study; Not GLP

Qualifier:

according to guideline

Guideline:

other: FHSLA

Principles of method if other than guideline:

Method: other: Federal Hazardous Substances Labeling Act (FHSLA), Federal Register Aug. 12, 1961, p 7333-7341, Part 191 "Hazardous Substances Definitions and Procedural and Interpretative Regulations, Final Order"

GLP compliance:

no

Species:

rabbit

Type of coverage:

occlusive

Preparation of test site:

abraded

Vehicle:

physiological saline

Amount / concentration applied:

Concentration: 500 mg

Duration of treatment / exposure:

24 hour(s)

Number of animals:

6

Details on study design:

The irritation produced by a single contact of each material with the skin was measured by a patch-test technique on the abraded and intact skin bellies of male, albino rabbits, clipped free of fur. One-half of a gram of the material was moistened with physiological saline and applied, under one-inch-square gauze patches to three intact and three abraded areas randomly distributed over the bellies of six male, albino rabbits. The patches were secured in place by adhesive tape and the trunks of the animals were wrapped in impervious plastic films to further secure the patches and retard the evaporation of the chemical. Following a 24-hour period of exposure, during which the rabbits were confined in stocks, the patches were removed and the skin reactions were evaluated on the basis of erythema, edema, and necrosis. The exposed areas were again evaluated after 72 hours. Areas of the skin which were damaged by the material were kept under observation for a maximum period of two weeks.

Irritation parameter:

primary dermal irritation index (PDII)

Score:

4.4

Irritation parameter:

erythema score

Remarks:

intact skin

Basis:

mean

Time point:

24/48/72 h

Score:

1.03

Max. score:

4

Reversibility:

fully reversible within: 2 weeks

Remarks on result:

other: 48 h value was considered to be the same as the 72 h value as worst case approach

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

1.4

Max. score:

4

Reversibility:

fully reversible within: 2 weeks

Remarks on result:

other: 48 h value was considered to be the same as the 72 h value as worst case approach

Flaked Grade: Not a primary irritant

Evaluation Time (hours)         Effect on skin
                        Erythema                    Edema
                 A. Intact        B. Abraded        C. intact        D. Abraded
24                 0.7                2.7*                 1.3                 3.0*
72                 1.2                3.5*                 1.5                 3.5*
Total              1.9                6.2*                 2.8                 6.5*

Primary Irritation score [(A+B+C+D)/4]: 4.4
*Based upon necrotic areas being scored 4.0, the maximum score possible, for both eythema and edema.

The contact of 0. 5 gm of the test material with the intact and abraded areas of the skin of male, albino rabbits for a maximum period of 24 hours produced responses, the most severe of which were: Intact, moderate irritation; Abraded, necrosis; primary
irritation score, 4. 4 for the Flaked Grade.

In general, after 72 hours exposure, the effects of the skin were more prevalent than at 24 hours following exposure.

After 14 days the necrotic areas were still encrusted or scarred but other areas were free of any signs of irritation.

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Conclusions:

The primary irritation score was calculated to be 4.4 for the Flaked Grade and is considered  by the author to no be an irritant. When evaluated in association with EC 1272/2008 (CLP), the substance is considered a Category 2 Irritant.

Executive summary:

A twenty four-hour, occluded application of flaked and industrial grade resorcinol at 500 mg to the bellies of male albino rabbits (strain not specified) resulted in moderate irritation on intact skin and necrosis on abraded sites with flaked grade resorcinol (Flickinger, 1976 and Koppers Company, 1962; RL=2 (provides basic data)).  Industrial grade resorcinol results varied after 24 hours from slight to severe irritation of the intact areas and from severe irritation to necrosis of the abraded areas.  After the 14 day recovery period the necrotic areas were either still encrusted or scarred but the other areas were free of any signs of irritation.  The primary irritation scores for flaked and industrial grade resorcinol were 4.4 and 5.4, respectively

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Link to relevant study records

Reference

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:

other: Guideline Study; Not GLP

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: FHSLA

Principles of method if other than guideline:

The study was conducted in accordance with Federal Hazardous Substance Labeling Act (FHSLA), Federal Register Aug 12, 1961, p 7333-7341, Part 191 "Hazardous Substances Definitions and Procedural and Interpretative Regulations, Final Order".

GLP compliance:

no

Species:

rabbit

Strain:

other: albino

Vehicle:

unchanged (no vehicle)

Amount / concentration applied:

Amount applied: 0.1 other: gm

Duration of treatment / exposure:

72 hour(s)

Number of animals or in vitro replicates:

6

Details on study design:

Six male albino rabbits were treated in determining the extent of injury that might be expected following accidental contamination of the eyes with each material. Two to four hours prior to the application of the material upon the cornea and into the conjunctival sac, the eyes were stained with fluorescein to assure the use of undamaged eyes. Since the material was water soluble, the standard test procedure was modified to test both the dissolved material and the semi-solid in its usual state. One tenth of a gram of the material was applied to one eye of each of six rabbits, the six untreated eyes serving as controls. The exposed eyes were not washed following application of the material. The eyes were examined and evaluated at 24 hours, 48 hours, and 72 hours after treatment for gross damage to the palpebral and bulbar conjunctivae, to the iris, and to the cornea. All damaged eyes were examined periodically thereafter for a maximum period of two weeks to evaluate the permanence of the damage and the rate and degree of repair.

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

24/48/72 h

Score:

105

Max. score:

110

Reversibility:

not reversible

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24/48/72 h

Reversibility:

not fully reversible within: 14 days

Remarks on result:

positive indication of irritation

Irritation parameter:

iris score

Basis:

mean

Time point:

24/48/72 h

Reversibility:

not fully reversible within: 14 days

Remarks on result:

positive indication of irritation

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

24/48/72 h

Reversibility:

not fully reversible within: 14 days

Remarks on result:

positive indication of irritation

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24/48/72 h

Reversibility:

not fully reversible within: 14 days

Remarks on result:

positive indication of irritation

Irritant / corrosive response data:

There was no significant difference in the response of the eyes of rabbits to Flaked or Industrial Resorcinol. Upon the application of 0.1 gm of either of the test materials into the eyes of male, albino rabbits, the conjunctivae became inflamed, the corneas opaque, and the rabbits gave evidence of marked discomfort. Examination at 24 hours post exposure showed severe conjunctivitis, iritis, corneal opacities occluding most of the iris, and corneal ulcerations. There was almost no perceptible improvement in the condition of the eyes during the observation period and by the 14th-day, all of the exposed eyes revealed kerataconus and pannus formation. The test substance, therefore, is an eye irritant as defined in the regulations pursuant to the FHSLA.

Using Draize methods, a numerical evaluation of the eye injuries at 24, 48 and 72 hours gave a resultant total eye irritation scores of 105, 105 and 105, respectively, with a maximum obtainable score of 110 for each time period. Classified as an eye irritant.

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria

Conclusions:

The author concluded the substance to be a severe eye irritant. The results were evaluated in association with EC 1272/2008 (CLP) and the substance was determined to be classified corrosive to the eye due to the lack of improvement in the condition of the eyes over the 14 day observation period.

Executive summary:

Following the FHSLA protocol, six male albino rats were administered 0.1 gram of flaked and industrial grade resorcinol in a dissolved and semi-solid state into one eye with the other eye serving as the control (Flickinger, 1976; Koppers Company, 1962). At administration, the conjunctivae became inflamed, corneas were opaque and discomfort was observed. At 24 hours post exposure, observations included severe conjunctivitis, iritis, corneal opacities occluding most of the iris and corneal ulcerations. There was almost no perceptible improvement in the condition of the eyes during the observation period and by the 14thday, all of the exposed eyes revealed kerataconus and pannus formation. Total eye irritation scores following Draize method were 105/110 at 24, 48 and 72 hours. Resorcinol was concluded to be a severe eye irritant.

Following evaluation based on the criteria in EC 1272/2008 (CLP) the substance was determined to be classified corrosive to the eye due to the lack of improvement in the condition of the eyes over the 14 day observation period.  

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irreversible damage)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Skin Irritation: Studies in Animals

500 mg resorcinol powder moistened with 0.1 mL water was administered to intact and abraded skin of 6 albino rabbits (strain not specified)(Koppers Company, 1970).  The only noted effects were for erythema to both intact and abraded sites at 24 and 72 hours.  The irritation is stated to be 0.5/8 with the total mean score equal to 2.0.  No other effects were noted for erythema or edema.

A twenty four-hour, occluded application of flaked and industrial grade resorcinol at 500 mg to the bellies of male albino rabbits (strain not specified) resulted in moderate irritation on intact skin and necrosis on abraded sites with flaked grade resorcinol (Flickinger, 1976 and Koppers Company, 1962).  Industrial grade resorcinol results varied after 24 hours from slight to severe irritation of the intact areas and from severe irritation to necrosis of the abraded areas.  After the 14 day recovery period the necrotic areas were either still encrusted or scarred but the other areas were free of any signs of irritation.  The primary irritation scores for flaked and industrial grade resorcinol were 4.4 and 5.4, respectively.

 

In an OECD TG  404 study, resorcinol was applied to New Zealand White rabbits for four hours at doses of 0.5 mL prepared from a concentration of 2.5%(w/w) in vehicle under semi-occlusive conditions (CIT, 2006).  Evaluations were conducted at 1, 24, 48 and 72 hours.  No cutaneous reactions were observed during the study and the substance was considered not irritating. 

 

Eye Irritation: Studies in Animals

Following the FHSLA protocol, six male albino rats were administered 0.1 gram of flaked and industrial grade resorcinol in a dissolved and semi-solid state into one eye with the other eye serving as the control (Flickinger, 1976; Koppers Company, 1962). At administration, the conjunctivae became inflamed, corneas were opaque and discomfort was observed.  At 24 hours post exposure, observations included severe conjunctivitis, iritis, corneal opacities occluding most of the iris and corneal ulcerations.  There was almost no perceptible improvement in the condition of the eyes during the observation period and by the 14^th day, all of the exposed eyes revealed kerataconus and pannus formation.  Total eye irritation scores following Draize method were 105/110 at 24, 48 and 72 hours. Resorcinol was concluded to be a severe eye irritant.

 

Six albino rats were administered 100 mg dry powder resorcinol resulting in mean scores of 56.3, 45.0 and 39.9 out of 110 at 24, 48 and 72 hours, respectively (Koppers Company, 1970). Additional details regarding this study were not available.

 

In a study conducted similar to OECD test guideline 405, a single dose of 0.1 mL of resorcinol at a concentration of 2.5% in water was considered non-irritating after administration to 3 New Zealand White rabbits’ left eyes while the right eyes served as the control (CIT, 2006).  Mean scores calculated for each animal over 24, 48 and 72 hours were 0.0, 0.0, and 0.0 for chemosis, iris lesions and corneal opacity, respectively. In the case of redness of the conjunctiva, scores were 0.0, 0.0 and 0.3, respectively. 

Effects on skin irritation/corrosion: moderately irritating

Effects on eye irritation: irreversible damage

Effects on respiratory irritation: irritating

Justification for classification or non-classification

Resorcinol is slightly to severely irritating to the skin and severely irritating to eyes when administered in a dissolved and semi-solid state. A twenty four-hour, occluded application of flaked and industrial grade resorcinol at 500 mg to the bellies of male albino rabbits (strain not specified) resulted in moderate irritation on intact skin and necrosis on abraded sites with flaked grade resorcinol.

Resorcinol was concluded to be a severe eye irritant. Following the FHSLA protocol, six male albino rats were administered 0.1 gram of flaked and industrial grade resorcinol in a dissolved and semi-solid state into one eye with the other eye serving as the control. At administration, the conjunctivae became inflamed, corneas were opaque and discomfort was observed. At 24 hours post exposure, observations included severe conjunctivitis, iritis, corneal opacities occluding most of the iris and corneal ulcerations. There was almost no perceptible improvement in the condition of the eyes during the observation period and by the 14th day, all of the exposed eyes revealed kerataconus and pannus formation. Total eye irritation scores following Draize method were 105/110 at 24, 48 and 72 hours.

No information was available on respiratory irritation, but based on irritation effects observed on the skin and eyes of experimental animals it is likely that respiratory irritation will also be observed.