D-gluconic acid

Endpoint summary

Description of key information

Skin irritation studies on gluconic acid in rabbits, one of which was performed according to test guidelines and in compliance with GLP, have demonstrated that the test compound is not a skin irritant.  
Eye irritation studies on gluconic acid in rabbits, one of which was performed according to test guidelines and in compliance with GLP, have demonstrated that the test compound is not an eye irritant. 

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Skin Irritation/Corrosion

The skin irritation potential of gluconic acid was assessed in rabbits in a GLP-compliant study performed according to OECD Guidelines for the Testing of Chemicals No. 404 (Mortier, 2009). In this study, New Zealand White rabbits were exposed to 0.5 mL of undiluted gluconic acid on the clipped dorsal under semi-occlusive conditions. The adjacent non-treated areas served as controls. Gluconic acid was applied to one rabbit three times successively for a period of three minutes, one hour, and four hours, respectively. A single application of gluconic acid was tested on two additional animals for a period of 4 hours. Any cutaneous lesions were evaluated at approximately 1, 24, 48, and 72 hours after removal of the dressing. Skin reactions were scored according to a prescribed numerical system. No erythema or edema were observed in any animals tested throughout the observation period. Under the experimental conditions adopted, gluconic acid was reported to be non-irritant for the skin of the rabbit. Gluconic acid is not classified as a skin irritant according to CLP (EC 1272/2008).

In another skin irritation study, gluconic acid (50% in water) was reported to cause very slight erythema in 3 out of 6 rabbit after 4 hours of exposure under occlusive conditions (Van Beek and Prinsen, 1984). After 72 hours, these effects had cleared up completely. Based on the results, the authors concluded that the test substance gluconic acid is not a skin irritant; however, the results of this study report are considered to be unreliable due to significant methodological deficiencies. Gluconic acid is not classified as a skin irritant according to CLP (EC 1272/2008).

Eye Irritation

An eye irritation study on gluconic acid has been performed in accordance with OECD Guidelines for the Testing of Chemicals No. 405 and in compliance with GLP (Mortier, 2009). In this study, 0.1 mL of undiluted gluconic acid was instilled into the eye lids of each of 3 New Zealand White rabbits. Ocular changes were assessed and recorded immediately at 1, 24, 48, and 72 hours after treatment. Scoring was performed according to guideline methods. Signs of irritation persisted in one animal and observations up to Day 8 were recorded. No observations indicative of systemic toxicity or ill health were noted for any rabbit during the course of this study. One hour after instillation, all animals had slight to moderate chemosis and moderate to severe redness of the conjunctivae. Two animals also had lacrimation, lesions of iris, and one of them had corneal lesions. Twenty-four hours after instillation, one animal had severe chemosis with lacrimation and severe redness of the conjunctivae, lesions of iris, and cornea. The two other animals had slight chemosis and slight redness of conjunctivae, and one of them also had lacrimation and lesions of the iris. Forty-eight hours after instillation, only one animal had signs (severe chemosis with lacrimation and severe redness of the conjunctivae, lesions of iris, and of the cornea). Seventy-two hours after instillation, only slight chemosis and slight redness of the conjunctivae persisted in one animal. No ocular lesion persisted in any animal at the end of the exposure period (i.e., reversibility by 72 hours for two animals and by Day 8 for one animal). Based on the results, gluconic acid was found to be slightly irritating to rabbit eyes. Gluconic acid is not classified as an eye irritant according to CLP (EC 1272/2008).

Similar results were reported in another eye irritation study conducted in New Zealand White rabbits (Van Beek and Prinsen, 1984). The test substance gluconic acid (50% in water) generally caused slight redness and slight swelling of the conjunctivae; however, these effects resolved after 72 hours. Based on the results, the test substance gluconic acid is slightly irritating to rabbit eyes. Gluconic acid is not classified as an eye irritant according to CLP (EC 1272/2008).

Effects on eye irritation: slightly irritating

Justification for classification or non-classification

The substance does not meet the criteria for classification and labelling for this endpoint, as set out in Regulation (EC) NO. 1272/2008.