Nitrile hydratase recombinant from E.coli

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
In accordance with REACH Annex XI, section 2, an eye irritation study is not required as testing is technically not possible as a consequence of the properties of the substance. The substance, nitrile hydratase, is a substance that is handled in a state where a mixture of the enzyme and the dead bacteria that produced it is dispersed in water. A fundamental requirement for testing the physicochemical properties of a substance, is that the substance is tested as such, excluding all solvents. However, since the higher order structure of the constituent molecules of the proposed substance (nitrile hydratase) is damaged by the removal of water, it cannot be said that the proposed substance would be correctly evaluated by performing this test after the removal of water. It should therefore be avoided.

In order to avoid deterioration it would be possible to conduct the test by leaving the substance as a suspension (i.e. dispersed in water). However, to do so would render the test results meaningless as the physical properties of water would greatly influence the results of such a test. As such, it would not be possible to consider the results of any such test as indicative of the physicochemical properties of the substance as such.

Additionally, there are substantial in vivo animal data on all industrially applied enzyme classes, as well as in vitro data performed before formal validation, for both skin and eye irritancy. These data document that enzymes are not irritating, with the exception of proteases. Non-proteases lack the potential to be skin and eye irritants but proteases show a range of effects from no irritation to moderate irritation. It is, however, only the most concentrated and reactive samples which show an effect which is transient in nature and commonly is classified as mild irritation (1; 2; in-house industrial data). This is also the outcome of clinical investigations (3; 4; 5), confirming that enzymes at the product use concentration, even with exaggerated exposures, do not give rise to any occupational or consumer risk of skin or eye irritation. Given the above, 'in vitro’ eye irritation testing is not considered to add any scientific value nor lead to a change in the classification adopted from existing data (in-house industrial data).

References:
1. AMFEP. Amfep paper on safety evaluation of technical enzyme products with regards to the REACH legislation. 2009. AMFEP.
2. HERA Human and environmental risk assessment on ingredients of household cleaning products - alpha-amylases, cellulases and lipases. 2005.
3. Basketter, D.A., English, J.S., Wakelin, S.H., and White, I.R. (2008) Enzymes, detergents and skin: facts and fantasies. British journal of dermatology 158, 1177-1181
4. Griffith, J.F., Weaver, J.E., Whitehouse, H.S., Poole, R.L., Newmann, E.A. and Nixon, G.A. (1969) SAFETY EVALUATION OF ENZYME DETERGENTS ORAL AND CUTANEOUS TOXICITY IRRITANCY AND SKIN SENSITIZATION STUDIES. Food and Cosmetics Toxicology 7, 581-593
5. White, I.R., Lewis, J. and El Alami, A. (1985) Possible adverse reactions to an enzyme-containing washing powder. Contact Dermatitis 13, 175-179