Registration Dossier
Registration Dossier
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EC number: 200-157-7 | CAS number: 52-89-1
Endpoint summary
Administrative data
Description of key information
In a study on the acute dermal toxicity with rats L-Cysteine hydrochloride monohydrate showed no
dermal irritation or other test article related changes after 24 hours of occlusive dermal treatment with
2000 mg/kg bw. .
L-Cysteine hydrochloride is regarded as not irritating to the eye and does not require classification based
on the in vitro BCOP-test.
In accordance with article 2(7)(b) and Annex V 6., REACH the hydrate free form of L-Cysteine hydrochloride is registered. L-Cysteine hydrochloride monohydrate (CAS 7048-04-6, hydrate part of the molecule = 10.25 %) is the manufactured and imported substance and was used for testing.
It is generally accepted that water and especially water of crystallisation has no toxicologically relevant effects. Therefore, the effect levels of L-Cysteine hydrochloride monohydrate can be used to calculate the corresponding dosages of L-Cysteine hydrochloride (anhydrous (free of water of crystallisation)).
Thus, the conclusion on hazard assessment and classification holds true for the anhydrous form as well.
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:
- no adverse effect observed (not irritating)
Respiratory irritation
Endpoint conclusion
- Endpoint conclusion:
- no study available
Additional information
Skin irritation / corrosion:
A GLP-study on the acute dermal toxicity revealed no test article related changes. Further, no symptoms of local skin irritation at the ears of mice in an LLNA-test were observed.
Eye irritation:
Based on the available eye irritation study on bovine eyes (BCOP-test) with no severe irritation / no corrosion potential it can be concluded that eye irritation potential is unlikely.
Justification for selection of skin irritation / corrosion endpoint:
A reliable acute dermal toxicity study (Acute dermal toxicity, Colas 2012) is available. L-Cysteine hydrochloride monohydrate showed no dermal irritation or other test article related changes after 24 hours of occlusive dermal treatment.
Justification for classification or non-classification
L-Cysteine hydrochloride and L-Cysteine hydrochloride monohydrate do not need to be classified with regards to skin irritation/ corrosion and Eye irritation according to the criteria laid out in Regulation (EC) No.: 1272/2008 based on the following data.
- Occlusive dermal application of 2000 mg L-Cysteine hydrochloride monohydrate / kg bw. for 24h did not cause any test article related changes.
- Eye irritation study on bovine eyes (BCOP-test) with no severe irritation / no corrosion potential.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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