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Administrative data

Description of key information

NOAEL (subacute, rat, m/f) ≥ 1000 mg/kg bw/day (OECD 407)

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Quality of whole database:
The available information comprises adequate, reliable (Klimisch score 1) and consistent studies, and is thus sufficient to fulfil the standard information requirements set out in Annex VIII, 8.6, of Regulation (EC) No 1907/2006.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Mode of Action Analysis / Human Relevance Framework

Additional information

Repeated dose toxicity oral

Subacute

A preliminary dose-range finding with the test substance over a period of 14 days was performed in rats as outlined in OECD 407 to provide a basis for the selection of dose levels for a subsequent 28-day repeated dose oral toxicity study (Holalagoudar, 2012). During the study period, the test substance diluted in sterile water was administered 7 days/week at dose levels of 250, 500 and 1000 mg/kg bw/day to groups of 3 male and 3 female Crl:WI (Han) rats by oral gavage. A similar constituted group received the vehicle (sterile water) and served as control. There were no clinical signs recorded in any of the animals during the treatment period. No mortalities and no clinical signs of toxicity were observed in any of the animals during the study. Body weights development and food intake were not affected in treated animals when compared to corresponding control group. In males, the individual and mean values of examined haematological parameters (haematocrit (HCT), haemoglobin (Hb), red blood cell count (RBC), platelet count (PLT) and white blood cells (WBC)) of treatment groups were within the biological range and comparable to the corresponding control group. In females, treatment-related decrease in mean values of WBC was observed among all dose groups compared to the controls. At necropsy, no macroscopic findings and no changes in organ weights attributable to treatment were observed in any animal. Based on the results of this study, doses levels of 100, 300 and 1000 mg/kg bw/day were considered to be adequate for the 28-day oral repeated dose toxicity study in rats.

In a GLP-conform 28-day toxicity study according to OECD 407, groups of each 5 male and 5 female Crl:WI (Han) rats received the test substance diluted in sterile water at 100, 300 and 1000 mg/kg bw/day via oral gavage (Holalagoudar, 2012). A control group, consisting of 5 animals per sex, was administered the vehicle (sterile water) alone. During the study period, no mortalities were observed in any of the treatment groups. Clinical signs of toxicity involved discoloured skin (reddish in colour) in animals treated with 1000 mg/kg bw/day of the test substance. The slight piloerection noted in 1/5 males of the 100 mg/kg bw/day group and the slightly increased spontaneous activity in 2/5 females of 300 mg/kg bw/day group were considered incidental. Furthermore, also a few unspecific findings like alopecia and eschar (1/5 females in the 300 mg/kg bw/day group) and exophthalmos (1/5 males in the 1000 mg/kg bw/day) were observed after administration of the test substance. However, these findings were considered to be of spontaneous nature and not related to treatment. Detailed clinical examination, ophthalmological examination and investigation of the parameters of the functional observation battery did not reveal any test substance-related findings when compared to controls. Body weights, body weight gain and food consumption were comparable between treated and control animals. Haematological analysis revealed a statistically significant increase in mean corpuscular haemoglobin concentration (MCHC) and eosinophil count in males treated with 1000 mg/kg bw/day compared to controls. MCHC was also significantly increased in females treated with 300 mg/kg bw/day. Since these changes were within the historical control range, they were not considered to be toxicologically relevant. Due to the high variability among treated animals, changes in blood coagulation parameters in males of the 100 mg/kg bw/day group were also not considered to be treatment-related.

At clinical chemistry analysis, a considerable and treatment-related decrease in mean total bile acids (TBA) was noted in males and females treated with 1000 mg/kg bw/day. Furthermore, a consistent increase in total bilirubin (TBIL) concentration was noted in both male and female animals of all dose groups, showing a clear dose response pattern and attaining statistical significance at higher dose levels. However, in the absence of any histopathological changes in liver, this finding was considered to be non-adverse. In males treated with 1000 mg/kg bw/day, a statistically significant decrease in mean activity of aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), alkaline phosphatase (AP), and a statistically significant increase in mean concentrations of total protein (TP) and cholesterol was noted. The mean ASAT activity was also decreased in males of the 300 mg/kg bw/day group. However, the decrease in ASAT and ALAT activity was not considered to have biological relevance, whereas the observed changes in AP, TP and cholesterol were very likely to be treatment-related. In females, the statistically significant increase in the mean concentration of AP and TP at 300 and/or 1000 mg/kg bw/day was not considered to be of toxicological relevance, since changes were either within the range of historical controls or not dose-related.

Visual examination of the urine revealed a yellowish to orange and rose or reddish colouration in animals of all dose groups, which were considered to be a result of excretion of the red-coloured test substance in the urine. Individual females of the 1000 mg/kg bw/day group also showed increases in the concentrations of urinary urobilinogen and bilirubin as well as elevated levels of leukocytes in urine. In the absence of corresponding effects noted during microscopic examination of kidneys or in haematology and clinical biochemistry, the toxicological relevance of these findings was not clear.

Macroscopic examination of treated animals revealed discoloured organs at and above 300 mg/kg bw/day. These findings were due to absorbed test item and, under the conditions of this study, without toxicological significance. Marginal changes in organ weights of thymus, adrenal gland, spleen and ovary as well as mild to marked increase in uterus weights were not associated with any histopathological alterations in the respective organs, and were thus not considered to be adverse effects. At histopathological examination, minimal or mild epithelial hyperplasia of the limiting ridge observed in the non-glandular part of the stomach in a majority of males and females at 1000 mg/kg bw/day was considered to be of toxicological relevance. However, this effect was most likely a result of local irritation of the test item formulation. Based on the results of the study, the NOAEL for male and female rats was greater than 1000 mg/kg bw/day.


Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
The selected study is the most adequate and reliable study based on overall assessment of quality, duration and dose descriptor level (refer to the endpoint discussion for further details).

Justification for selection of repeated dose toxicity inhalation - systemic effects endpoint:
Study not required according to Annex VIII of Regulation (EC) No. 1907/2006.

Justification for selection of repeated dose toxicity inhalation - local effects endpoint:
Study not required according to Annex VIII of Regulation (EC) No. 1907/2006.

Justification for selection of repeated dose toxicity dermal - systemic effects endpoint:
Study not required according to Annex VIII of Regulation (EC) No. 1907/2006.

Justification for selection of repeated dose toxicity dermal - local effects endpoint:
Study not required according to Annex VIII of Regulation (EC) No. 1907/2006.

Justification for classification or non-classification

Based on the available data on repeated dose toxicity via the oral route, the test substance does not meet the criteria for classification according to Regulation (EC) No 1272/2008 or Directive 67/548/EEC.