Disodium; 4-Amino-3-{4-[4-(2,4-diamino-phenylazo)-benzenesulfonylamino]-phenylazo}-5-hydroxy-6-phenylazo-naphthalene-2,7-disulfonate

Endpoint summary

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Effects on fertility

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

150 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Additional information

Similar substance 1 was tested for fertility and developmental effects through repeated 42 day oral administration to wistar rats by gavage at the dose levels of 50, 150 and 450 mg/kg/day during the premating, mating, gestation and lactation period

Though, a slight dose dependent decrease in the sperm motility was observed at all the doses tested together with an increased percentage of sperm affected by changes in morphology, these effects did not affect females fertility up to the dose of 450 mg/kg bw/day . In fact, mating and reproductive performance, fertility index, conception length and conception index were actually higher in animals treated at 50, 150 and 450 mg/kg bw/day compared to controls. The number of corpora lutea, implantations, and delivery of live pups were similar (or even higher) between the groups treated at the dose of 50, and 150 mg/kg bw/day with respect to the controls and neither abortion nor decrease in live pups were observed up to the dose of 150 mg/kg bw/day. On the contrary at the dose of 450 mg/kg bw/day a decrease in the number of live pups, a slight decreased number of females achieving pregnancy and a slight decreased number of implantations have been observed. Marked pigment accumulation was observed at the dose of 450 mg/kg bw/day in several tissues, such as lymph nodes, brain, liver, thyroid and even ovaries. Though no additional clear functional or histopathological correlation were observed at the highest dose, it is likely that the effects observed on reproductive parameters might be related to the induced toxicity of the test compound on haematological and biochemical parameters (as observed in the sub-acute branch of the test). Thus, the effects observed on reproduction and development at the highest dose can be addressed as secondary non specific consequences of a marked toxicity on haematological and immune progenitors cells, which in turn might have decrease self defence mechanisms and detoxification pathways. For these reasons, though slight modulations have been observed for reproduction parameters in males at 50 and 150 mg/kg/day, a NOAEL of 150 mg/kg bw/day was expected for reproductive toxicity as no effects on fertility parameters and mating/reproductive indices have been observed.

A Dose range finding following OECD 422 has been performed on Acid Black 234 in order to strengthen the reliability of the read across and demonstrate that similar effects can be seen.

The evaluation of reproduction parameters revealed slightly increased resorptions at the dose level 150 and 450 mg/kg/day and slightly decreased the body weight of foetuses at the dose level 150 mg/kg/day. Sperm motility and morphology not showed significant changes.

Read across evaluation is attached in section 13.

Short description of key information:

NOAEL for reproduction toxicity is 150 mg/kg bw/day

Effects on developmental toxicity

Description of key information

NOAEL for developmental toxicity is 450 mg/kg bw/day

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

450 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

No developmental toxicity in offspring was observed up tot he dose of 150 mg/kg bw/day. A decrease number of pups per litter was observed at both dose of 50 and 450 mg/kg bw/day, but not at 150 mg/kg bw/day, where the number of pups actually increased. A decrease in the number of live pups was observed at 450 mg/kg bw/day, though no morphological or clinical changes were observed in all living pups treated at all doses

Justification for classification or non-classification

Reproductive toxicity includes adverse effects on sexual function and fertility in sexually adult males and females animals, as well as developmental toxicity in the offspring. However, developmental toxicity essentially means all the adverse effects induced during pregnancy that can be manifested at any point of the life span of the animal, which might in turn bring to structural abnormality, altered growth and/or organs development, functional deficiency, even death.

Table 3.7.1(a) of Annex I of EC Regulation 1272/2008 states that to classify compounds "for category 2 suspected human reproductive toxicant, reproductive effects shall have been observed in the absence of other toxic effects, or if occurring together with other toxic effects the adverse effect on reproduction is considered not to be a secondary non-specific consequence of the other toxic effects". To this extent this study does not provide any indication of direct adverse effect on reproduction. In fact up to the dose of 450 mg/kg bw/day effects observed on reproduction are considered to be of low or minimal toxicological significance, since fertility parameters were not modified but were in some instances even increased. On the contrary, the effects observed at the dose of 450 mg/kg bw/day (slight decrease in sperm motility, decreased number of live pups, slight increased pre-implantation and post-implantation loss) are considered to be secondary non-specific consequences of other chemically induced-perturbation of maternal homeostasis as observed in the repeated dose toxicity test, which are manifested at unrealistically high levels of the substance that might in turn result in the saturation of kinetic processes of detoxification. Moreover, no significant developmental toxic effects in the offspring were observed at all doses.

In conclusion, since no adverse effects on reproduction were observed, classification for reproductive/developmental toxicity is not warranted under Regulation 1272/2008