Chlorhexidine

Repeated dose toxicity: dermal

Administrative data

Endpoint:

sub-chronic toxicity: dermal

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The study was conducted with chlorhexidine diacetate and not with the chlorhexidine base. Due to the fact that it is a simple salt form showing even a higher solubility and therefore a possibly higher dermal absorption, the results derived from this studies are considered to be predictive also for chlorhexidine base. This internal company report is not available for publicity. However, methods and results have been reported in a summarised format by Cal EPA and US EPA.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1988

Reference 2

Reference Type:

secondary source

Title:

Summary Of Toxicology Data. Chlorhexidine Diacetate

Author:

Cal EPA

Year:

2003

Bibliographic source:

Medical Toxicology Branch. Department Of Pesticide Regulation. California Environmental Protection Agency

Reference 3

Reference Type:

secondary source

Title:

Reregistration Eligibility Decision (RED). Chlorhexidine Diacetate

Author:

US EPA

Year:

1996

Bibliographic source:

Office of Prevention, Pesticides and Toxic Substances (OPPTS). United States Environmental Protection Agency (US EPA), Washington, D.C.

Materials and methods

Principles of method if other than guideline:

No detailed information available

GLP compliance:

not specified

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Chlorhexidine di(acetate)

EC Number:

200-302-4

EC Name:

Chlorhexidine di(acetate)

Cas Number:

56-95-1

IUPAC Name:

N',N'''''-hexane-1,6-diylbis[N-(4-chlorophenyl)(imidodicarbonimidic diamide)] diacetate

Details on test material:

-Purity: 97.7 %
-Lot/batch No.: R4796

Test animals

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

-Age at study initiation: ca. 12 weeks
No further detailed information available

Administration / exposure

Type of coverage:

occlusive

Vehicle:

water

Details on exposure:

The test substance was applied moistened with 2 ml of water to the intact dorsal dermal surface and the treatment area was covered with a gauze dressing and wrap.

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

13 consecutive weeks

Frequency of treatment:

6 h/d on 5 d/week

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 250, 500 or 1000 mg/kg bw/d
Basis:

No. of animals per sex per dose:

10 m / 10 f

Control animals:

yes

Details on study design:

The dose selection was justified as being a limit dose of 1000 mg/kg bw/d and choosing logarithmically spaced doses for the mid- and low-dermal doses.
No further detailed information available.

Examinations

Observations and examinations performed and frequency:

see below

Sacrifice and pathology:

No further detailed information available.

Statistics:

Fishers exact test

Results and discussion

Results of examinations

Details on results:

Body weight and food consumption were slightly lowered during the initial 2 weeks of the study. At all doses minimal dermal irritation such as erythema, edema, desquamation and fissuring was observed. There were no adverse effects on ophthalmology or haematology.
In females treated with >= 500 mg/kg bw/d the activities of aspartate aminotransferase and of alanine aminotransferase were increased at the end of the study.
The incidence of hepatocellular degeneration/necrosis in males was 0, 0, 0, 1 and 0, 1, 5, and 7 in females. However, the liver necrosis was graded as minimal in all animals and the incidence of 1/10 at 250 mg/kg bw/d was not statistically significant.

Effect levels

Dose descriptor:

NOEL

Effect level:

360 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: A dermal NOEL was not established as there were local effects at all doses in both sexes. For systemic effects a NOEL of 250 mg/kg bw/d (corresponding to 360 mg chlorhexidine digluconate/kg bw/d) was derived based on liver findings at higher doses.

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Under the conditions of the assay, dermal application of chlorhexidine diacetate to rabbits for 13 weeks led to minimal liver necrosis in animals dosed with >= 500 mg/kg bw/d. A dose of 250 mg/kg bw/d was associated with local effects such as irritation but there were no statistically significant systemic effects.

Executive summary:

For chlorhexidine digluconate itself there are no standardized studies available performed according to recent guidelines. Therefore, data for chlorhexidine diacetate have been taken into further consideration.

In a 13 -week dermal toxicity study with NZW rabbits, chlorhexidine acetate was applied at doses of 0, 250, 500, or 1000 mg/kg bw/d to the intact dorsal dermal surface on 6 h/d and 5 d/week under occlusive conditions.

Body weight and food consumption were slightly lowered during the initial 2 weeks of the study. At all doses minimal dermal irritation such as erythema, edema, desquamation and fissuring was observed. There were no adverse effects on ophthalmology or haematology.

In females treated with >= 500 mg/kg bw/d the activities of aspartate aminotransferase and of alanine aminotransferase were increased at the end of the study.

The incidence of hepatocellular degeneration/necrosis in males was 0, 0, 0, 1 and 0, 1, 5, and 7 in females. However, the liver necrosis was graded as minimal in all animals and the incidence of 1/10 at 250 mg/kg bw/d was not statistically significant.

A dermal NOEL was not established as there were local effects at all doses in both sexes. For systemic effects a NOEL of 250 mg/kg bw/d (corresponding to 360 mg chlorhexidine digluconate/kg bw/d) was derived based on liver findings at higher doses.