Troclosene sodium

Endpoint summary

Description of key information

Troclosene sodium is corrosive to skin and eyes

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Justification for read across for studies with sodium dichloroisocyanurate dihydrate:

The chlorinated isocyanurates (sodium dichloroisocyanurate and sodium dichloroisocyanurate dihydrate) produce free available chlorine, in the form of hypochlorous acid (HOCl) as they dissolve in water. As the equilibria involve all of the possible chlorinated isocyanurates, the toxicity of sodium dichloroisocyanurate (NaDCC) and sodium dichloroisocyanurate dihydrate (NaDCC.2H2O) will be virtually equivalent at the same available chlorine concentration. The parent compound for all chlorinated isocyanurates is isocyanuric acid (cyanuric acid). All of the chlorinated isocyanurates are essentially equivalent, once they are dissolved in water at the low concentrations at which they are used. Therefore read across from sodium dichloroisocyanurate dihydrate to troclosene sodium is justified.

Skin irritation:

A skin irritation study is available for sodium dichloroisocyanurate dihydrate (Gargus 1985). The test substance was applied to the intact skin of 3 female and 3 male rabbits for an exposure of 24 hours. Dermal responses were graded and scored at 30 -60 minutes, 24, 48, 72 and 96 hours and on days 7, 10, 14 and 21.Very slight to moderate erythema was observed in all sites at 30 to 60 minutes after patch removal through 24 hours. Very slight to slight edema was observed in five sites at 30 to 60 minutes through 24 hours. Dermal effects included thickening, blanching, necrosis, epidermal scaling, raw areas and compound adhered to the skin. These observations concluded that the test material is corrosive to skin.

Eye irritation:

Two eye irritation studies are available. In what is considered the key study with troclosene sodium (Wnorowski 1995) 0.1 g of test material was instilled into one eye of six healthy rabbits (3 male and 3 female). The other eye remained untreated with the test substance and served as a control. Ocular irritation was evaluated by the method of Draize. Severe irritation, including corneal opacity, pannus, iritis and conjunctivitis was noted in all treated eyes throughout the study. Only a slight decrease in the incidence and severity of irritation was noted through day 21. The observations concluded that the test substance is corrosive to eyes. In a supporting study (Gargus 1984) 0.1g sodium dichloroisocyanurate dihydrate was instilled into the eye of six rabbits. Eye irritation was scored and graded at 1, 24, 48 and 72 hours and on days 4 and 7. Severe eye irritation involving the cornea, iris and conjunctivae was noted in all rabbits. On day 7 the corneas of all rabbits were not observable due to nictatating membrane which was adhered to the cornea and insome rabbits the cornea appeared ruptured. The iris was not observable due to extreme opacity in all rabbits by day 7. Due to the severity of the damage to eyes animals were sacrificed after 7 days.

Effects on skin irritation/corrosion: corrosive

Effects on eye irritation: corrosive

Effects on respiratory irritation: irritating

Justification for classification or non-classification

The skin and eye irritation studies clearly demonstrated that the test substance is corrosive. Read across is justified for the skin irritation study performed with NaDCC dihydrate.

In the skin irritation study the exposure time was 24 hours. CLP states that where the substance is classified as corrosive but the data used for classification does not allow differentiation between the skin corrosion subcategories 1A/1B/1C, then the substance should be assigned skin corrosive Category 1. In this case as the exposure time was 24 hours we are unable to classify into a subcategory .

Under CLP the substance should be classified as skin corrosivity category 1. A skin corrosive substance is considered to also cause serious eye damage which was also reflected in the eye irritation studies. The hazard statement H 314: Causes severe skin burns and eye damage therefore should also be applied.    

According to CLP it is a reasonable assumption that corrosive substances may also cause respiratory tract irritation (RTI) when inhaled at exposure concentrations below those causing frank respiratory tract corrosion. If there is evidence from animal studies or from human experience to support this then Cat 3 may be appropriate. In general a classification for corrosivity is considered to implicitly cover the potential to cause RTI and so the additional Category 3 is considered to be superfluous although it can be assigned at the discretion of the classifier. The Category 3 classification would occur only when more severe effects in the respiratory system are not observed. a Cat 3 classification for respiratory irritation has therefore not been assigned.