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Description of key information

An oral 28D study in rats has been conducted on a  24-26% cetrimonium chloride solution with dose-levels of 0; 30; 100; and 300 mg/kg bw/d (corresponding to 0; 7.5; 25, and 75 mg/kg bw/d). The dose was given as gavage in 10 ml of water/ kg bw. The NOAEL was 25 mg/kg bw/d. At 75 mg/kg bw/d severe local effects in the stomach was noted (thickening of forestomach mucosa, sporatic ilceration. Slight increase in adrenal  weight and slight decrease in spleen weight were also noted at this dose level but this was only considered as possible and not clear systemic effects.

In an oral 1-year study rats were dosed via drinking water with cetrimonium bromide at 0; 10; 20 and 45 mg/kg bw/d. No histopathological findings were observed in the stomach (only organ subject to histopathological examination).  At 45 mg/kg bw/d significant and persistent decrease in body weight was observed in male which was suggested to be due to lower observed efficiency of food conversion. The authors concluded that cetrimonium bromide may potentially prevent proper nutrition by increasing the rate of gastric emptying and intestinal transit and/or interfering with absorption of nutritional substances.

In an evaluation of the study by the SCCS, a NOAEL of 10 mg/kg bw/d from this study was concluded.

In a 28D dermal study with rabbits dosed on 25% of their body surface with 10 mg/kg bw/d ( 2 ml/kg bw/d) no systemic effects were noted.

However, the exposed skin showed mild to marked acanthosis with active mitosis, hyperkeratosis, and partial to extensive necrosis of the epidermis and hair follicles, partly with encrustation and exudate.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records
Reference
Endpoint:
chronic toxicity: oral
Type of information:
other: published study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The published study is well described. The study was not performed according to GLP and no guideline was given.
Reason / purpose for cross-reference:
reference to other study
Principles of method if other than guideline:
No guideline is given.
GLP compliance:
no
Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
3-4 weeks old housed in groups of 5 animals with free access to food and water
Route of administration:
oral: drinking water
Details on oral exposure:
The rats were given CTAB in drinking water in concentrations calculated to deliver doses of approximately 10, 20, and 45 mg/kg/day. The concentrations of CTAB in drinking water were increased during the study so that the intake of test substance per bodyweight was approximately constant throughout the experimental period. When the animals attained maturity (6-7 weeks on test) the concentrations of CTAB in drinking water were 0.007, 0.014, and 0.032%.
Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
56-60 weeks
Frequency of treatment:
Daily
Remarks:
Doses / Concentrations:
10, 20, 45 mg/kg/day
Basis:
nominal in water
No. of animals per sex per dose:
10
Control animals:
yes
Details on study design:
Animals were distributed in 4 experimental groups of 10 males and 10 females each, balanced with respect to body weights.
Observations and examinations performed and frequency:
The body weight, the length of the tail of each animal, and food and water consumption collectively for groups of 5 animals were recorded weekly during the first two months, biweekly during months 3 and 4 and monthly thereafter. Regular observations were made of the appearance and behavior of the animals.
Sacrifice and pathology:
The animals were killed 50-60 weeks after the beginning of the experiment. Blood was collected by heart puncture. Differential counts, haemoglobin determinations, quantitative determinations of serum protein, electrophoretic separation of serum proteins and determination of Na+ and K+ contents in serum were carried out. The liver, kidneys, heart, sleen, stomach, caecum, and submaxillary salivary glands were weighed. Specimens of the stomach and small intestine were fixed in buffered formalin, embedded in paraffin wax, and stained with Heidenhain's azan or kernechtrot.
Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
Wetting and discoloration of ventral fur of 50% of the animals in the 45 mg/kg/day dosage group
Mortality:
mortality observed, treatment-related
Description (incidence):
Wetting and discoloration of ventral fur of 50% of the animals in the 45 mg/kg/day dosage group
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Reduced weight of the 45 mg/kg/day dosage group, males throughout the test period, females up to week 9 of the study
Food efficiency:
effects observed, treatment-related
Description (incidence and severity):
Decreased food efficiency of males in the 45 mg/kg/day dosage group up to week 8 of the study
Haematological findings:
no effects observed
Urinalysis findings:
no effects observed
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
Reduced relative liver weight in males and increased relative caecum weight in both sexes in the 45 mg/kg/day dosage group. Increased relative caecum weight in males in the 20 mg/kg/day dosage group
Gross pathological findings:
effects observed, treatment-related
Description (incidence and severity):
Reduced skeletal growth in the 45 mg/kg/day dosage group
Dose descriptor:
NOAEL
Effect level:
10 mg/kg bw/day (nominal)
Based on:
act. ingr.
Sex:
male/female
Basis for effect level:
other: Clinical signs; body weight; food efficiency; haematology; gross pathology; organ weights; histopathology
Critical effects observed:
not specified
Conclusions:
Based on the results from the reported study it is concluded that cetrimonium bromide, when continuously administered in large doses, may potentially prevent proper nutrition by increasing the rate of gastric emptying and intestinal transit and/or by interfering with the absorption of nutritional substances. A NOAEL of 10 mg/kg/day is derived.
Executive summary:

A publication from 1976 reports the adverse effects observed in groups of 10 male and 10 female Sprague Dawley rats when treated orally for one year with 10, 20 and 45 mg cetrimonium bromide/kg bw/day. The following effects were noted:

10 mg/kg bw/day: - no statistically significant effects were observed

20 mg/kg bw/day: - increased relative caecum weight in males

45 mg/kg bw/day: - significantly reduced mean body weights in both sexes after

3 weeks, persisting till end of study in males and for 9 weeks in

females

- males: significantly decreased efficiency of food conversion

- significantly reduced skeletal growth (judged by the growth of the

tail) in both sexes

- wetting and discoloration of ventral fur, often associated with a

brown discoloration of the fur

- males: reduced relative liver weight

- increased relative caecum weight in both sexes

No compound related changes were observed in haematological and clinical laboratory analyses of blood and urine. No gross necropsy changes were seen, and no microscopic alterations were found in the wall of stomach and small intestine of treated rats. No other tissues were subjected to histopathological examination.

Based on the results from the reported study it is concluded that cetrimonium bromide, when continuously administered in large doses, may potentially prevent proper nutrition by increasing the rate of gastric emptying and intestinal transit and/or by interfering with the absorption of nutritional substances. A NOAEL of 10 mg/kg/day is derived.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
10 mg/kg bw/day
Study duration:
chronic
Species:
rat
Quality of whole database:
Klimisch score 2. The systemic effects observed (reduced growth) is considered secondary to local effects in the gastrointestinal tract leading to decrease in feed efficiency of the animals.

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

Link to relevant study records
Reference
Endpoint:
short-term repeated dose toxicity: dermal
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1979
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Read-across to cetrimonium bromide from data on cetrimonium chloride (with data reliability value of 1). Read-across justifications are provided in the endpoint summary.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)
Deviations:
yes
Remarks:
only one dose level used; dosing area 25% of body surface
GLP compliance:
not specified
Limit test:
yes
Species:
rabbit
Strain:
New Zealand White
Sex:
male/female
Duration of treatment / exposure:
4 weeks
Frequency of treatment:
6.5 to 7.0 h, 5 days a week
Remarks:
Doses / Concentrations:
10 mg/kg bw/d
Basis:

No. of animals per sex per dose:
5
Control animals:
yes
Observations and examinations performed and frequency:
observations for signs of toxicity and for mortality: twice a day
dermal irritation: scored daily
body weight: measured weekly
blood samples: taken prior to dosing and at week 4 for hematologic analyses
necropsy: either at the time of death or at the end of the study when they are killed
Clinical signs:
no effects observed
Description (incidence and severity):
no death
Dermal irritation:
effects observed, treatment-related
Description (incidence and severity):
slight to moderate erythema
Mortality:
no mortality observed
Description (incidence):
no death
Body weight and weight changes:
no effects observed
Haematological findings:
no effects observed
Details on results:
Slight to moderate erythema was observed in all of the treated rabbits between days 4 and 8 but disappeared in four rabbits by day 17.
Very slight to slight edema was observed between days 6 and 12 in four rabbits and subsided by day 17.
Two rabbits had intermittent evidence of slight edema on day 20. No evidence of desquamation or coriaceousness was present in three rabbits. In the other rabbits, slight atonia was observed but persisted into week 4 in only three animals. Very slight to slight desquamation and coriaceousness was noted in most of the rabbits, but desquamation was found only in three animals and coriaceousness in two animals by week 4. Slight fissuring was observed in most of the rabbits but typically disappeared by the end of the study.
At necropsy, treatment-related changes were found only in the skin. The application sites of two rabbits were reddened, and one rabbit hadscabbing. Findings from microscopic examination included mild to marked acanthosis with active mitosis, hyperkeratosis, and partial to extensive necrosis of the epidermis and hair follicules with or without encrustation with exudate. No statistically significant changes were observed for the hepatic or renal weights between the experimental and control animals.

(The dose level of 10 mg/kg bw/d correspons to a dermal load of 0.05 mg/cm2 (assuming 25% of a body surface of 2500 cm2 (625 cm2) and a body weight of 3 kg)
Dose descriptor:
LOAEL
Remarks:
dermal irritation
Effect level:
10 mg/kg bw/day (nominal)
Based on:
dissolved
Sex:
male/female
Basis for effect level:
other: no systemic effects were noted
Critical effects observed:
not specified
Conclusions:
Although some treatment related changes were observed on the skin, they were mostly reversible. No deaths occurred in the experimental group, and no evidence of toxicity or hematological changes was present at the dose of 10 mg/kg bw/day.
Executive summary:

Five New Zealand albino rabbits/sex/group were treated cutaneously with the test substance (cetrimonium chloride for 5 days/week for 4 weeks at a dose of 0 or 10 mg/kg bw/day (0 or 0.5% aqueous solutions, respectively). The dosage volume was 2.0 ml/kg bw with an approximate exposure period of 6.5 to 7 hours.

There were no treatment-related effects on body weight, haematology, organ weight, gross necropsy findings or histopathology, except for treated areas of the skin that showed mild to marked acanthosis with active mitosis, hyperkeratosis, and

partial to extensive necrosis of the epidermis and hair follicles, partly with encrustation and exudate.

(The dose level of 10 mg/kg bw/d correspons to a dermal load of 0.05 mg/cm2 (assuming 25% of a body surface of 2500 cm2 (625 cm2) and a body weight of 3 kg)

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
10 mg/kg bw/day
Study duration:
subacute
Species:
rabbit
Quality of whole database:
Klimisch score 2

Repeated dose toxicity: dermal - local effects

Link to relevant study records
Reference
Endpoint:
short-term repeated dose toxicity: dermal
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1979
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Read-across to cetrimonium bromide from data on cetrimonium chloride (with data reliability value of 1). Read-across justifications are provided in the endpoint summary.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)
Deviations:
yes
Remarks:
only one dose level used; dosing area 25% of body surface
GLP compliance:
not specified
Limit test:
yes
Species:
rabbit
Strain:
New Zealand White
Sex:
male/female
Duration of treatment / exposure:
4 weeks
Frequency of treatment:
6.5 to 7.0 h, 5 days a week
Remarks:
Doses / Concentrations:
10 mg/kg bw/d
Basis:

No. of animals per sex per dose:
5
Control animals:
yes
Observations and examinations performed and frequency:
observations for signs of toxicity and for mortality: twice a day
dermal irritation: scored daily
body weight: measured weekly
blood samples: taken prior to dosing and at week 4 for hematologic analyses
necropsy: either at the time of death or at the end of the study when they are killed
Clinical signs:
no effects observed
Description (incidence and severity):
no death
Dermal irritation:
effects observed, treatment-related
Description (incidence and severity):
slight to moderate erythema
Mortality:
no mortality observed
Description (incidence):
no death
Body weight and weight changes:
no effects observed
Haematological findings:
no effects observed
Details on results:
Slight to moderate erythema was observed in all of the treated rabbits between days 4 and 8 but disappeared in four rabbits by day 17.
Very slight to slight edema was observed between days 6 and 12 in four rabbits and subsided by day 17.
Two rabbits had intermittent evidence of slight edema on day 20. No evidence of desquamation or coriaceousness was present in three rabbits. In the other rabbits, slight atonia was observed but persisted into week 4 in only three animals. Very slight to slight desquamation and coriaceousness was noted in most of the rabbits, but desquamation was found only in three animals and coriaceousness in two animals by week 4. Slight fissuring was observed in most of the rabbits but typically disappeared by the end of the study.
At necropsy, treatment-related changes were found only in the skin. The application sites of two rabbits were reddened, and one rabbit hadscabbing. Findings from microscopic examination included mild to marked acanthosis with active mitosis, hyperkeratosis, and partial to extensive necrosis of the epidermis and hair follicules with or without encrustation with exudate. No statistically significant changes were observed for the hepatic or renal weights between the experimental and control animals.

(The dose level of 10 mg/kg bw/d correspons to a dermal load of 0.05 mg/cm2 (assuming 25% of a body surface of 2500 cm2 (625 cm2) and a body weight of 3 kg)
Dose descriptor:
LOAEL
Remarks:
dermal irritation
Effect level:
10 mg/kg bw/day (nominal)
Based on:
dissolved
Sex:
male/female
Basis for effect level:
other: no systemic effects were noted
Critical effects observed:
not specified
Conclusions:
Although some treatment related changes were observed on the skin, they were mostly reversible. No deaths occurred in the experimental group, and no evidence of toxicity or hematological changes was present at the dose of 10 mg/kg bw/day.
Executive summary:

Five New Zealand albino rabbits/sex/group were treated cutaneously with the test substance (cetrimonium chloride for 5 days/week for 4 weeks at a dose of 0 or 10 mg/kg bw/day (0 or 0.5% aqueous solutions, respectively). The dosage volume was 2.0 ml/kg bw with an approximate exposure period of 6.5 to 7 hours.

There were no treatment-related effects on body weight, haematology, organ weight, gross necropsy findings or histopathology, except for treated areas of the skin that showed mild to marked acanthosis with active mitosis, hyperkeratosis, and

partial to extensive necrosis of the epidermis and hair follicles, partly with encrustation and exudate.

(The dose level of 10 mg/kg bw/d correspons to a dermal load of 0.05 mg/cm2 (assuming 25% of a body surface of 2500 cm2 (625 cm2) and a body weight of 3 kg)

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LOAEL
0.05 mg/cm²
Study duration:
subacute
Species:
rabbit

Additional information

No clear systemic effects have been observed in the repeated dose toxicity studies with cetrimonium chloride and cetrimonium bromide.

The local effects are considered the most critical effects in connection with repeated exposure.

The lack of systemic effects in the repeated dose toxicity studies may be explained by a low dermal and oral absorption rates as indicated by the toxicokinetic studies where absorption rates for dermal and oral exposure have been estimated to 3% and 6%, respectively.

As seen from the repeated dose toxicity studies the potent local effect of the substance very much limit the exposure levels to be used in repeated dose toxicity studies for further examining systemic effects. Thus there seems to be no rationale for further testing of cetrimonium bromide at ANNEX IX level.

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:

The only available RDT study on cetrimonium bromide (1 year study).

Justification for selection of repeated dose toxicity dermal - systemic effects endpoint:

28D repeated dermal toxicity study on cetrimonium chloride for read-across to cetrimonium bromide

Justification for selection of repeated dose toxicity dermal - local effects endpoint:

28D repeated dermal toxicity study on cetrimonium chloride for read-across to cetrimonium bromide

Repeated dose toxicity: via oral route - systemic effects (target organ) digestive: other

Justification for classification or non-classification

Using read-across to the 28D oral study on cetrimonium chloride where severe effects were noted in the gastrointestinal tract at a dose level of 75 mg/kg bw/d the substance (cetrimonium bromide) should according to the CLP regulation be classified as STOT RE 2; H373 (oral route; gastrointestinal tract)