Citral

Endpoint summary

Additional information

Skin irritation / corrosion:

Skin irritation of the test substance was assessed in several internal BASF tests:

Occlusive application of citral for 1 min, 15 min, and 2 hours on 2 Vienna White rabbits led to increasing irritation scores for erythema and edema, depending on the application duration. The individual mean scores (including 24 h and 48 h observation time points) ranged from 2 to 3 for erythema and edema in both animals and persisted until the end of the observation period (8 days). In addition, all animals show desquamation at the end of the observation period. After occlusive application for 20 hours on two rabbits, individual mean erythema and edema scores (including 24 h and 48 h observation time points) increased to 4 and 3, respectively, and did marginally decline over the 8 day observation period. Furthermore, both animals show soft and parchment-like necroses indicating a severe skin irritating potential (BASF 1978a).

In line, occlusive application of citral for 1 hour on 2 rabbits showed individual irritation scores (mean including 24 h and 48 h observation time points) above 2.3 for erythema and above 2 for edema. Inflammatory reactions persisted until the end of the observation period, i.e. 8 days, and desquamation was observed (BASF 1978b).

Occlusive application of citral on 6 Vienna White rabbits for 4 hours resulted in erythema and edema scores (mean scores including 24 h and 48 h observation time points and all animals) of 2.3 and 2.4, respectively, and signs of dermal inflammation were still observed at the end of the observation period (8 days). Furthermore, desquamation in all animals, parchment-like necrosis in one animal and hard but slidable necrosis in 2 of 6 animals was observed at the end of the observation period (BASF 1978c).

Studies cited from secondary sources with limited information on test design and results (reliability: not assignable) reported citral to be corrosive

in rabbits after dermal application for 24 hours (Monsanto 1992) or moderately to markedly irritating in rabbits after dermal occlusive application for 24 hours (Moreno 1974).

Since no test is available, which meets current standart procedures, the available relevant studies are assessed in a weight of evidence approach.

Taken together, the studies have been performed mainly occlusive, representing a worst case exposure scenario. In the BASF studies, severe necrosis was observed in 2 rabbits after a 4 hour occlusive application, however a more stringent treatment, i.e. 20 hour occlusive application did not result in a severe tissue destruction. The majority of studies, reported from secondary sources, identified citral to be irritating to the skin.

Eye irritation:

In the chosen key study (BASF, 1978), 50 µl citral was applied to the conjunctival sac of one eye of two White Vienna rabbits (no eye wash after 24 hours). The saline-treated second eye served as control. Readings of eye scores were made on the day of treatment after 1 and 3 hrs, and after 24 hrs, 48 hrs, 5 days, 7 days and 8 days .This study was comparable to OECD Guideline 405 with several deviations (reduced test substance volume, 2 test animals, no reading after 72 hrs, observation period shortened to 8 days). Mean scores of 24 and 48 h readings for animal 1/animal 2 were for corneal opacity 1/1, iritis 0/0, conjunctiva redness 1/1.5, and chemosis 1/1.5. Corneal opacity and chemosis were fully reversible within 7 days, whereas the conjunctival redness declined but not completely resolved during the study period (score 1/1 after 8 days).

Effect level: empty Endpoint conclusion: Adverse effect observed

Effect level: empty Endpoint conclusion: Adverse effect observed

Justification for classification or non-classification

Skin irritation:In a weight of evidence approach the test material fulfils the criteria under 67/548/EEC and CLP to be classified as irritating to the skin (R38 and Category 2).

Eye irritation:

According to the the mean scores observed for corneal opacity, and the lack of reversibility for conjunctival redness within 7 days, the substance is considered to be irritating to the eyes (Cat 2) according to 1272/2008/EEC, whereas a non-classification is warranted according to criteria laid down in 67/548/EEC.