Hydrogen peroxide-urea

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Data source

Reference

Reference 1

Reference Type:

review article or handbook

Title:

Unnamed

Year:

2003

Report date:

2003

Reference 2

Title:

Unnamed

Year:

1997

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

not specified

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Hydrogen peroxide

EC Number:

231-765-0

EC Name:

Hydrogen peroxide

Cas Number:

7722-84-1

Molecular formula:

H2O2

IUPAC Name:

hydrogen peroxide

Test material form:

liquid

Specific details on test material used for the study:

CAS number: 7722-84-1
Purity: not stated

Test animals

Species:

mouse

Strain:

other: C57BL/6NCrBR

Remarks:

catalase-deficient

Sex:

male/female

Details on test animals or test system and environmental conditions:

not specified

Administration / exposure

Route of administration:

oral: drinking water

Vehicle:

water

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:

35% hydrogen peroxide was diluterd with distilled water to 100, 300, 1000 and 3000 ppm solutions.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

90 days

Frequency of treatment:

daily, 7/week

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 ppm

Remarks:

control groups

Doses / concentrations 2

Dose / conc.:

100 ppm

Doses / concentrations 3

Dose / conc.:

300 ppm

Doses / concentrations 4

Dose / conc.:

1 000 ppm

Doses / concentrations 5

Dose / conc.:

3 000 ppm

No. of animals per sex per dose:

15

Control animals:

yes

yes, concurrent vehicle

Details on study design:

15 animals/sex/group received hydrogen peroxide solutions for 90 day via drinking water. At term, 10 males and female per group were subjected to examinations.
5 animals/sex/group continued on untreated distilled water for a 6-week recovery period.

Positive control:

not needed

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Not specified

DETAILED CLINICAL OBSERVATIONS: Not specified

BODY WEIGHT: Yes
- Time schedule for examinations: Not specified

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: not specified

OPHTHALMOSCOPIC EXAMINATION: Not specified

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at termination
- Anaesthetic used for blood collection: Not specified
- Animals fasted: Not specified
- How many animals: 10/sex/group

CLINICAL CHEMISTRY: Not specified
- Time schedule for collection of blood: at termination
- Animals fasted: Not specified
- How many animals: 10/sex/group

URINALYSIS: Not specified

Sacrifice and pathology:

GROSS PATHOLOGY: Yes

HISTOPATHOLOGY: Yes
Histological examinations were performed on all gross lesions, on the tongue, esophagus, stomach, duodenum, ileum, jejunum, caecum, colon, and rectum from all animals in all groups, and on all major organs including the sex organs in the high dose and control animals.

Results and discussion

Results of examinations

Clinical signs:

not specified

Mortality:

mortality observed, non-treatment-related

Description (incidence):

One male mouse died in the control group (the cause of death was undetermined), and one male mouse in the 3000 ppm group died on study day 43 (no histopathological findings).

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Body weights were significantly reduced only in male and female animals receiving 3000 ppm.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Dose-related reductions in both food and water consumption were observed in female animals receiving 300 ppm and greater, while among the males consistent reductions were observed at the top dose level.

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

effects observed, treatment-related

Description (incidence and severity):

Dose-related reductions in both food and water consumption were observed in female animals receiving 300 ppm and greater, while among the males consistent reductions were observed at the top dose level

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Hydrogen peroxide related changes were observed only in the duodenum at terminal sacrifice in the 1000 and 3000 ppm groups of males and females, and in a single 300 ppm group male. Although the general architecture of the affected duodenum was normal, there was an increase in cross sectional diameter and a larger mucosal area with broader, more substantial villi when compared to those of control mice. The change was assessed as mucosal hyperplasia because of the increase in mucosal thickness and size of the villi.

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Mucosal hyperplasia in the duodenum in animals at 1000 or 3000 ppm, and in one male at 300 ppm

Histopathological findings: neoplastic:

no effects observed

Effect levels

1

Key result

Dose descriptor:

NOAEL

Effect level:

100 ppm

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

food consumption and compound intake

gross pathology

histopathology: non-neoplastic

water consumption and compound intake

2

Key result

Dose descriptor:

NOAEL

Effect level:

26 mg/kg bw/day (actual dose received)

Based on:

act. ingr.

Sex:

male

Basis for effect level:

body weight and weight gain

food consumption and compound intake

gross pathology

histopathology: non-neoplastic

water consumption and compound intake

3

Key result

Dose descriptor:

NOAEL

Effect level:

37 mg/kg bw/day (actual dose received)

Based on:

act. ingr.

Sex:

female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

water consumption and compound intake

Target system / organ toxicity

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

300 ppm

System:

gastrointestinal tract

Organ:

duodenum

Treatment related:

yes

Dose response relationship:

yes

Relevant for humans:

yes

Any other information on results incl. tables

Histological examinations revealed no changes (examined: all gross lesions, tongue, esophagus, stomach, duodenum, ileum, jejunum, caecum, colon, and rectum from all animals in all groups, and on all major organs including the sex organs in the high dose and control animals).

Recovery period:

- The most notable effect was increased water consumption observed among males that had received 3000 ppm, and among females that had received 300, 1000 or 3000 ppm.

- After the recovery period no hyperplasia was seen in any dose group.

Applicant's summary and conclusion

Conclusions:

The NOAEL was 100 ppm (26 and 37 mg/kg/day) for males and females, respectively.

Executive summary:

Reportedly, the sub-chronic toxicity of hydrogen peroxide was examined in a drinking water study (FMC, 1997; dose levels: 0, 100, 300, 1000, and 3000 ppm) using catalase-deficient male and female mice (15/sex/group). At termination after 90 days, 10 animals/sex/group were sacrificed and examined (blood, body weights, gross pathology, histopathology. The latter included all gross lesions, tongue, esophagus, stomach, duodenum, ileum, jejunum, caecum, colon, and rectum from all animals in all groups, and on all major organs including the sex organs in the high dose and control animals). The remaining 5 animals/sex/group continued on distilled water during a 6-week recovery period.

Effects during the treatment period (Days 0-90): There were no treatment-related deaths. Clear treatment-related, dose-dependent effects were noted among both females and males receiving 300, 1000 or 3000 ppm of H₂O₂. Body weights were significantly reduced only in male and female high-dose animals receiving 3000 ppm. Dose-related reductions in both food and water consumption were observed in female animals receiving 300 ppm and greater, while among the males consistent reductions were observed only at the top dose level. Among females 300 ppm (103 mg/kg/day) was a LOAEL based on significant reduction in water consumption. Histopathology revealed treatment-related effects only in the duodenum of males and females at 1000 and 300 ppm, and in one male at 300 ppm. Although the general architecture of the affected duodenum was normal, there was an increase in cross sectional diameter and a larger mucosal area with broader, more substantial villi when compared to those of control mice. The change was assessed as mucosal hyperplasia because of the increase in mucosal thickness and size of the villi. Mucosal hyperplasia was not found in 100 ppm group mice, neither among controls. No other histopathological changes were noted on the tongue, esophagus, stomach, duodenum, ileum, jejunum, caecum, colon, and rectum from all animals in all groups, and on all major organs including the sex organs in the high dose and control animals.

Recovery period: the most notable effect was increased water consumption observed in males that had received 3000 ppm, and among females that had received 300, 1000, or 3000 ppm. Mucosal hyperplasia was reversible, as no such lesion was seen in any dose group after the recovery period.

The NOAEL was 100 ppm (26 and 37 mg/kg bw/day) in this study for males and females, respectively, based on dose-related reductions in water and food consumption, and on the observation of duodenal mucosal hyperplasia (ECB, 2003).