Registration Dossier

Administrative data

Key value for chemical safety assessment

Effects on fertility

Effect on fertility: via oral route
Endpoint conclusion:
no study available
Effect on fertility: via inhalation route
Endpoint conclusion:
no study available
Effect on fertility: via dermal route
Endpoint conclusion:
no study available

Effects on developmental toxicity

Effect on developmental toxicity: via oral route
Endpoint conclusion:
no study available
Effect on developmental toxicity: via inhalation route
Endpoint conclusion:
no study available
Effect on developmental toxicity: via dermal route
Endpoint conclusion:
no study available

Toxicity to reproduction: other studies

Description of key information

No studies investigating toxicity to reproduction are available for hydroxy-estrenon (ZK5252). However, ZK 5252 has a structural similarity to ZK 5221, which is classified as anabolic steroid according to German legislation (TRGS-905).

There are two publications and internal data on the interaction of ZK 5252 and sex hormone receptors:

ZK 5252 showed a binding affinity towards the androgen receptor which was lower compared to ZK 5221 [Ojasoo et al. (1987) Towards the mapping of the progesterone and androgen receptors. J Steroid Biochem. 27: 255 -69]

Internal data from transactivational assays also showed androgenic potential of ZK 5252 at 10 nM and 1 µM, which were, however, in a similar range compared to ZK 5221. Further, ZK 5252 showed a binding affinity towards the estrogen receptor, which was higher compared to ZK5221. The agonistic/antagonistic profile at the progesterone receptor of ZK 5252 was comparable to the profile of ZK 5221.

ZK 5252 showed activity to inhibit aromatase reaction. [Schwarzel et al. (1973) Studies on the mechanism of estrogen biosynthesis. 8. The development of inhibitors of the enzyme system in human placenta. Endocrinology 92:866 -80]

In addition, the only difference between ZK 5252 and ZK 5221 is the position of one double bond between both substances. But the isomerisation of this double bond from 5,10 -position to 4,5 -position will easily occur in vivo. Therefore, a close effect relationship between ZK 5252 and ZK 5221 has to be assumed in vivo. These information were described in an internal communication by N. Schmees to A. Klaus (3. Jun 2016).

Justification for classification or non-classification

There are no studies on the reproduction toxicity of hydroxy-estrenon (ZK 5252) available. However, ZK 5252 showed comparable androgenic potential in vitro as the structural similar nandrolone (ZK 5221), which is classified according to German legislation (TRGS-905) for anabolic steroids as Repr. (F) Cat. 1A and Repr. (D) Cat. 1B. Further, ZK 5252 may be transformed to ZK 5221 in vivo.

Based on in vitro hormone receptor binding data and a read across to nandrolone (ZK 5221), ZK 5252 is classified with category Repr. (F) Cat. 1A and Repr. (D) Cat. 1 according to Regulation (EC) 1272/2008 (CLP).