Registration Dossier

Administrative data

Endpoint:
short-term repeated dose toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report Date:
2008

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity in Rodents)
Principles of method if other than guideline:
DBD/RENACIT 10 was administered daily via gavage in Cremophor EL (2%)/tap water to 5 male and 5 female Wistar rats per dose group, in doses of 0, 100, 300 or 1000 mg/kg body weight for a period of 4 weeks.
The animals were regularly observed and weighed. Food and water intake was determined. Functional Observational Battery (FOB) as well as Motor and Locomotor Activity (MA/LMA) tests and clinical laboratory investigations on blood samples were performed. Organs and tissues were subjected to gross and histopathological investigations and selected organs were weighed.
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
Test Item: DBD I RENACIT 10
Chemical name: N, N' -( dithiodi-2, 1-phenylene )bis-benzam ide
CAS No.: 135-57-9
Molecular Mass (g/mol): 456.59
Molecular Formula: C26H20N202S2
Content( s): 98.7%
Appearance: Gray, yellow powder
Storage: Room temperature

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: Cremophor EL (2%)/tap water
Analytical verification of doses or concentrations:
yes
Duration of treatment / exposure:
29 (males)/30 (females) days
Frequency of treatment:
daily
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 100, 300 or 1000 mg/kg bw for a period of 4 weeks
Basis:
actual ingested
No. of animals per sex per dose:
5 male and 5 female rats per dose group
Control animals:
yes, concurrent vehicle

Results and discussion

Effect levels

Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: see 'Remark'

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

The survival rate, clinical appearance, body weight gain as well as food and water intake of the rats were not affected up to 1000 mg/kg.

FOB measurements and MA/LMA tests did not indicate neurotoxicity.

There was no indication of test substance-related changes in blood parameters. Beginning at 100 mg/kg an increase in liver weights was seen in males, which was correlated with liver enlargement. In females increased relative liver weights were noted at 1 000 mg/kg.

One of five males each showed distinct liver lobulation beginning at 300 mg/kg.

Centrilobular liver hypertrophy was diagnosed at 1000 mg/kg in males.

Taken together there were indications of adaptive liver reaction beginning at 100 mg/kg in males and at 1000 mg/kg in females.

The serum concentrations of sodium, potassium, were not affected by the treatment.

In the renal tubules of males at 300 mg/kg and above degenerations with increased accumulation of hyaline droplets, indicating a rat specific and not human relevant alpha-globulin nephropathy, was diagnosed. P2 and P3 segments of the cortical tubules were characterized by slight tubular dilation, luminal debris or cast and epithelial degeneration. Moreover, basophilic cortical tubules were raised by severity at 300 mglkg and above in males. Slight transitional cell hyperplasia occurred in the renal pelvis of 1/5 males each at 300 and 1000 mg/kg. In females, basophilic cortical tubules were slighty increased at 1000 mg/kg.

Taken together in the rat toxicologically relevant changes were evident in them kidneys beginning at 300 mg/kg in males and at 1000 mg/kg in females, where the alpha-globulin nephropathy and tubular basophilia are not supposed to be relevant for humans.

There was no morphological correlate to elevated heart weight of 1000 mg/kg males.

Necropsy, organ weight measurements and histopathology revealed no toxicologically relevant alterations in the remaining organs investigated.

Applicant's summary and conclusion

Conclusions:
Toxicologically relevant changes were evident in the kidneys beginning at 300 mg/kg in males and at 1000 mg/kg in females, where the alpha-globulin nephropathy and tubular basophilia are not supposed to be relevant for humans. Necropsy, organ weight measurements and histopathology revealed no toxicologically relevant alterations in the remaining organs investigated.
Therefore for humans a NOAEL of 1000 mg/kg bw is justified.
Executive summary:

DBD/RENACIT 10 was administered daily via gavage in Cremophor EL (2%)/tap water to 5 male and 5 female Wistar rats per dose group, in doses of 0, 100, 300 or 1000 mg/kg body weight for a period of 4 weeks.

The animals were regularly observed and weighed. Food and water intake was determined. Functional Observational Battery (FOB) as well as Motor and Locomotor Activity (MA/LMA) tests and clinical laboratory investigations on blood samples were performed. Organs and tissues were subjected to gross and histopathological investigations and selected organs were weighed.

The test substance was stable in the vehicle for the duration of use. Formulations given to the rats were prepared appropriately.

The survival rate, clinical appearance, body weight gain as well as food and water intake of the rats were not affected up to 1000 mg/kg.

FOB measurements and MA/LMA tests did not indicate neurotoxicity.

There was no indication of test substance-related changes in blood parameters. Beginning at 100 mg/kg an increase in liver weights was seen in males, which was correlated with liver enlargement. In females increased relative liver weights were noted at 1 000 mg/kg.

One of five males each showed distinct liver lobulation beginning at 300 mg/kg.

Centrilobular liver hypertrophy was diagnosed at 1000 mg/kg in males.

Taken together there were indications of adaptive liver reaction beginning at 100 mg/kg in males and at 1000 mg/kg in females.

The serum concentrations of sodium, potassium, were not affected by the treatment.

In the renal tubules of males at 300 mg/kg and above degenerations with increased accumulation of hyaline droplets, indicating a rat specific and not human relevant alpha-globulin nephropathy, was diagnosed. P2 and P3 segments of the cortical tubules were characterized by slight tubular dilation, luminal debris or cast and epithelial degeneration. Moreover, basophilic cortical tubules were raised by severity at 300 mglkg and above in males. Slight transitional cell hyperplasia occurred in the renal pelvis of 1/5 males each at 300 and 1000 mg/kg. In females, basophilic cortical tubules were slighty increased at 1000 mg/kg.

Taken together in the rat toxicologically relevant changes were evident in them kidneys beginning at 300 mg/kg in males and at 1000 mg/kg in females, where the alpha-globulin nephropathy and tubular basophilia are not supposed to be relevant for humans.

There was no morphological correlate to elevated heart weight of 1000 mg/kg males.

Necropsy, organ weight measurements and histopathology revealed no toxicologically relevant alterations in the remaining organs investigated.

Under the conditions described a no-observed-effect-level (NOEL) can not be determined for males due to adaptative changes in the liver considered to be not adverse. Deduced from species-specific kjdney alterations, the no-observed-adverse-effect-level (NOAEL) is assigned at 100 mg/kg for male and at 300 mg/kg (=NOEL) for female rats.