Registration Dossier

Administrative data

Endpoint:
sub-chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2005
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study performed according to OECD guideline 408 in compliance to GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report Date:
2005

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity in Rodents)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Test substance : HC Blue No2
Batch number : 114B5
Purity : 98.7%

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: 0.5% carboxymethylcellulose in water
Duration of treatment / exposure:
13 weeks
Frequency of treatment:
Once daily
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
100 mg/kg bw/day
Basis:
actual ingested
Remarks:
Doses / Concentrations:
300 mg/kg bw/day
Basis:
actual ingested
Remarks:
Doses / Concentrations:
1000 mg/kg bw/day
Basis:
actual ingested
No. of animals per sex per dose:
Ten males and ten females per dose
Control animals:
yes, concurrent vehicle

Results and discussion

Results of examinations

Details on results:
Mortality
No unscheduled deaths occurred during the study.

Clinical Observations
All treated animals produced ptyalism, purple colour of urine, coat, tail and urogenital area with a dose related incidence. These findings were no longer observed during the treatment free period and were considered related to treatment, but not to represent adverse effects.

Functional Observation Battery
There were no perturbations of the autonomic or physiological functions in any treated group compared to controls.

Body Weight
No treatment related efects were noted on body weight in both sexes.

Food Consumption
No treatment related effects were noted on food consumption for either males or females.

Ophthalmology
There were no treatment related ophthalmic findings at the end of the treatment period.

Hematology and Blood Biochemistry
No treatment related changes were noted for any hematological or blood biochemical parameters.

Urinalysis
Due to the urine colouration, the only urinary parameter that could be evaluated was the urine volume which was similar in all treated groups compared to controls.

Toxicokinetics
The test item was well absorbed following oral administration. In the test item dose groups and in weeks 1 and 13 plasma levels of the test item were quantifiable at the first time-point and reached maximum levels between 0.5 and 4 hours post dosing. The test item was no longer detectable 24 hours after dosing at any dose level. There were minimal sex related differences. Except in the low dose treated group, no evidence of time effects was observed. The systemic exposure increased with dose levels in a dose proportional manner.

Organ Weights
No significant changes were observed at 100 and 300 mg/kg bw/day. Slightly higher absolute and/or relative liver and kidney weights were noted in males and females given 1000 mg/kg bw/day at the end of the dosing period and were still recorded in females at the end of the recovery period. As the concurrent individual data for relative organ weight changes in males and relative kidney weight increases in females given 1000 mg/kg bw/day fell within historical control ranges and were not associated with relevant histopathological or blood biochemical abnormalities, they were not considered to be adverse effects. In contrast, a relationship to treatment of relative liver weight elevations in females given 1000 mg/kg bw/day could not be excluded as some individual values exceeded or were close to historical control changes, though no histopathological or blood biochemical abnormalities were noted.

Macroscopic Findings
At the end of both treatment and treatment free periods, purple colourations of the hair and extremities and some intestinal parts were observed. These findings were due to the physical property of the test item and consequently of no toxicological importance.

Microscopic Findings
No treatment related findings were observed at any dose level.

Effect levels

Dose descriptor:
NOAEL
Effect level:
300 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: higher liver/kidney weights and biochemistry parameters observed at the highest dose

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
The test item, HC Blue No 2, when administered daily by gavage to Sprague-Dawley rats at the dose level of 100, 300 or 1000 mg/kg bw/day for 13 weeks was well absorbed and caused purple colouration of urine and, as a consequence, of extremities and excessive salivation in all the treated animals. At 1000 mg/kg bw/day, higher absolute and relative liver and kidney weights were observed in both sexes at the end of the dosing period and the recovery period (except for kidneys in males) while no changes were noted on hematology or biochemistry parameters. Only relative liver increases in females given 1000 mg/kg bw/day were considered to be test item related adverse effects. No treatment related findings were noted at histopathological examination. After a 4 week treatment free period, coloured urine and excessive salivation were no longer observed while the slight increase in liver weights were still observed in females given 1000 mg/kg bw/day. Under the experimental conditions of the study the NOAEL of the test item was considered to be 300 mg/kg bw/day.