Didecyldimethylammonium chloride

Endpoint summary

Description of key information

-         Key value from Registrant: oral LD50 = 264 mg a.i./kg bw (females); dermal LD50 = 3342 mg/kg bw

-         Key value from DDAC biocides assessment report for Product Type 8 (June 2015): oral LD50 = 238 mg a.i./kg bw; dermal LD50 = 3342 mg/kg bw

In the present report, the oral and dermal LD50 of 238 and 3342 mg a.i./kg bw was selected as key value, in line with the DDAC biocides assessment report for Product Type 8.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Species: Rat
Strain: Wistar (outbred SPF-Quality)
Source: BRL Ltd., Basel, Switserland
Sex: Male - 5, female - 5
Age/weight at study initiation:
group 1: Approx. 11 wks ; 235-265 g (males) and 183-211 g (females)
group 2&3: Approx. 8 wks; 197-260 g (males) and 182-200 g (females)
Number of animals per group: 5 male and 5 female / dose group
Control animals: Yes

Route of administration:

oral: gavage

Vehicle:

other: undiluted test material

Details on oral exposure:

Post-exposure period: 14 days
Type: Gavage
Concentration 2000 (group 1), 1000 (group 2) and 500 (group 3) mg/kg bw
(1000, 500 and 250 mg active ingredient/kg bw)
Concentration in vehicle: Undiluted test material, containg ca. 50% active material
Total volume applied; Group 1: 2.273 ml/kg; Group 2: 1.136 mL/kg; Group 3: 0.568 mL/kg
Controls: No control group
Examinations; Mortality, body weights, clinical signs and Gross necropsy for any macroscopic abnormalities

Doses:

500, 1000 and 2000 mg/kg bw.

No. of animals per sex per dose:

10

Control animals:

no

Details on study design:

Refer to details on oral exposure

Statistics:

No data

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

ca. 329 mg/kg bw

Based on:

act. ingr.

Key result

Sex:

male

Dose descriptor:

LD50

Effect level:

406 mg/kg bw

Based on:

act. ingr.

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

264 mg/kg bw

Based on:

act. ingr.

Mortality:

The mortality incidence for both sexes combined for high, mid and low dose group was 10/10, 9/10 and 2/10.

Clinical signs:

other: Effects noted following treatment were lethargy, piloerection, dyspnoea, rattled respiration, staggering gait and bloody eye/nose encrustation. The surviving animals recovered between days 8 and 15.

Gross pathology:

Necropsy of the decedents revealed mainly haemorrhages/red areas in glandular stomach or forestomach; discolouration of the stomach or intestinal content; irregular areas in the forestomach and adherence of spleen, pancreas, serosa of the forestomach, left lateral liver lobe and diaphragm to each other.
Animals that survived to the end of the study showed mainly the same effects.

LD50 combined = 658 mg/kg bw (i.e. 329 mg a.i./kg bw)

LD50, males = 812 mg/kg bw
LD50, females = 527 mg/kg bw

Interpretation of results:

other: Category 4

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

The combined acute oral LD50 of the test substance in Wistar rats was determined to 658 mg/kg bw (i.e. 329 mg a.i./kg bw) in males and females.

Executive summary:

An acute oral toxicity was performed in Wistar rats according to OECD Guideline 401 under GLP conditions. The test substance was orally gavaged once to 5 males and 5 female rats per group at doses of 250, 500 and 1000 mg a.i./kg bw. The post-exposure period was 14 days. The examinations performed included mortality, body weights, clinical signs and gross necropsy for any macroscopic abnormalities. The mortality incidence in both sexes combined for high, mid and low dose groups were 10/10, 9/10 and 2/10. Necropsy of the decedents revealed mainly haemorrhages/red areas in glandular stomach or forestomach; discolouration of the stomach or intestinal content; irregular areas in the forestomach and adherence of spleen, pancreas, serosa of the forestomach, left lateral liver lobe and diaphragm to each other. Animals that survived to the end of the study showed similar effects. The combined oral LD50 of the test substance in Wistar rats was determined to be 658 mg/kg bw (i.e., 329 mg a.i./kg bw) in males and females.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

238 mg/kg bw

Quality of whole database:

Good quality. In line with the data presented in the DDAC assessment report for Product Type 8 conducted under Directive 98/8/EC (evaluating Competent Authority: Italy, June 2015

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 May, 1996 - 12 June, 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Species: Rat
Strain: Wistar strain Crl:(WI) BR (outbred, SPF-quality)
Source: Charles River, Sulzfeld, Germany.
Sex: Males and females
Age/weight at study initiation: Approx. 9 weeks, 373 g (mean males) and 240 g (mean females)
Number of animals per group: 5 males and 5 females
Control animals: No

Vehicle:

water

Details on dermal exposure:

Postexposure period: 15 days
Type: Dermal
Concentration: 2000 mg/kg bw for 24 hours (dose volume: 10 ml/kg in distilled water)
Vehicle: Distilled water
Concentration in vehicle: 200 mg/ml (20%)
Total volume applied: 10 ml/kg
Controls: No

Doses:

Limit test at 2000 mg/kg bw.

No. of animals per sex per dose:

10

Control animals:

no

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 1 000 mg/kg bw

Based on:

act. ingr.

Clinical signs:

other: Lethargy was noted in all animals, between days 2 and 4. Hunched posture was observed in four females between days 2 and 6. Skin effects in the treated area: Swelling, necrosis and hardening of the back, scabs and brown skin on the back were noted in all

Gross pathology:

No abnormalities were found at macroscopic post mortem examination Of the animals.

Other findings:

At removal of the bandages (day 2) it was noticed that the bandages of two Females (number 9 and 10) had shifted caudally. The clinical signs shown by these animals were not significantly different compared to the other females. The exposure to the test substance was therefore considered sufficient.

No mortality occurred. Effects noted were lethargy in all animals between day 2 and 4 and skin effects which consisted
of swelling, redness, erythema and necrosis of the skin. The majority of the skin effects persisted until the end of the
observation time. No abnormalities were found at macroscopic post mortem examination.

Interpretation of results:

other: Category 4 based on EU CLP criteria

Conclusions:

The acute dermal LD50 of the test substance in rats was determined to be >2000 mg/kg bw (i.e. >1000 mg a.i./kg bw).

Executive summary:

A study performed according to GLP and OECD 402 and EU B.3 “Acute Dermal Toxicity”. Five male and five female rats received a dermal dose of 2000 mg/kg bw for 24 h (dose volume: 10 ml/kg in distilled water) under occlusive dressing for 24 h. One day before exposure (day -1) an area of approximately 5x7 cm on the back of the animal was clipped. 24 h, after which dressings were removed and residual test substance removed using a tissue moistened with tap water. Animals were subjected to daily observations and weekly determination of body weight. Macroscopic examination was performed after terminal sacrifice on day 15. No mortality occurred. Effects noted were lethargy in all animals between day 2 and 4 and skin effects which consisted of swelling, redness, erythema and necrosis of the skin. The majority of the skin effects persisted until the end of the observation time. No abnormalities were found at macroscopic post mortem examination. Effects are limited to local irritation/corrosion of the skin, without involvement of systemic toxicity. The acute dermal LD50 of the test substance in rats were determined to be >2000 mg/kg bw (i.e. >1000 mg a.i./kg bw).

As quaternary ammonium compounds do not easily pass biological membranes, dermal absorption of these compounds is very limited. The dermal toxicity of aqueous DDAC solutions is related to its corrosivety and therefore more related to the concentration of the administered solution then of the actual amount in mg/kg. Due to the direct corrosive effect, there is danger of irreversible damage to the skin upon exposure to the undiluted solution. Further toxicity is secondary to the local tissue damage, rather than the result of percutaneously absorbed material. Some reviews mention comparable dermal LD₅₀ data in rat from literature which is in the range 2000 – 3000 mg/kg bw.

Toxicity is related to concentration dependent cytotoxicity, with a lack of specific systemic toxicity. The toxicity (and efficacy as based on same mechanism of action) show a dependence on chain length, with an optimum at C₁₀-C₁₂. Therefore this test using C₁₀-chainlength can be seen as worst case representative for the whole group of DDAC compounds between C₈ and C₁₈. Furthermore, additional tests for acute dermal toxicity are not ethical due to its corrosive effects and can thus not be performed.

Reference 2

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 03 March 1987 to 17 March 1987

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: EPA protocol

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Remarks:

Albino

Sex:

male/female

Details on test animals or test system and environmental conditions:

ANIMALS AND ANIMAL HUSBANDRY
1. Strain/Species: Nev Zealand Albino Rabbits,
2. Source: An SIB and USDA approved animal supplier.
3. Number: 5 Males and 5 females per group.
4. Weight; Approximately 2.0 — 3.0 Kg, weight variations should not exceed +/—20 percent of the group mean of each sex.
5. Acclimation Period: At least 5 days.
6. Animal Identification: Plastic ear tags.
7. Food & Water: Commercial laboratory feed and water were freely available. No contaminants were anticipated in this" feed and water which would compromise the purpose of the study.
8. Housing & Animal Care: One per cage in suspended wire mesh bottom cage. 12/12 Hr. light./dark cycle. housing and care conforming to AAALAC standards and to those published in the "Guide for the Care and Use of Laboratory Animals", Publication No. 83-23.

Type of coverage:

occlusive

Vehicle:

other: 10% v/v non-denatured ethanol water solution

Details on dermal exposure:

1. On the day prior to dosing, the fur was clipped from the dorsal area of the trunkof the test animals using a small animal cupper. The clipped area was 20 * 12 cm, approximately the 10% of body surface area.
2. The test article was applied uniformly in the clipped area.
3. The test article was held in contact with skin for 24 h using porous 8 ply gauze dressing covered with rubber dam and secured with several wrappings of 3 inch elasoplast tape.
4. After the 24 hour exposure period, residual test article was removed where practicable using water

Duration of exposure:

24 h exposure

Doses:

DOSAGE LEVELS
1. Five male and 5 female animals were randomly assigned to each group.
2. A negative control group was dosed with a ethanolwater solution at the largest volume utilized the test population.
3. Five animals per sex were administered the test article at graded dose levels as follows:

Group 1: 552 mg/kg bw, 0.69 mL/kg bw
Group 2: 1104 mg/kg bw, 1.38 mL/kg bw
Group 3: 3328 mg/kg bw, 4.16 mL/kg bw
Group 4: 4448 mg/kg bw, 5.56 mL/kg bw

4. The test article was administered neat as provided by the Sponsor without further vehicle adjustments in concentrations.

No. of animals per sex per dose:

Five animals per sex

Control animals:

yes

Details on study design:

EXPERIMENTAL PROCEDURES
1. On the day prior to dosing, the fur was clipped from the dorsal area of the trunkof the test animals using a small animal cupper. The clipped area was 20 * 12 cm, approximately the 10% of body surface area.
2. The test article was applied uniformly in the clipped area.
3. The test article was held in contact with skin for 24 h using porous 8 ply gauze dressing covered with rubber dam and secured with several wrappings of 3 inch elasoplast tape.
4. After the 24 hour exposure period, residual test article was removed where practicable using water.

OBSERVATIONS
1. Animals were weighted individually on the day of dosing (day 1) and on days 8 and 15 of the study. All the animals which died on test after day 1 was weighted.
2. Animal were observed for mortality and toxic effects continuously for 8 hours post dose and daily thereafter until day 15. Cage side observation included skin and fur evaluations, eyes and muscous membranes; respiratory, CNS, ANS, behaviour patterns. Observation of tremors, convulsions, lethargy, depression, salivation and diarrhea.

TERMINATION
All animals that die during the study were necropsied as soon as possible and no later that 24 hours after the time of death. If animals that die cannot be necropsied immediately, apropriate precautions were taken to minimize the effects of autolysis. All survivors were euthanized at the end of the study using T—61 solution and necropsied as well at that time. The contents of all body cavities would be subjected to gross examinations with special attention given to the heart muscle and its auxiliary vascular system. Any gross pathology, particularly of the heart
that may be noted and suspect as dose—related, would be immediately brought to the attention of the Sponsor's Study Coordinator for final disposition of these tissues.

Statistics:

LD50 value with 95% confidence interval was calculated using probit analysis method whereever possible

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

ca. 3 342 mg/kg bw

Based on:

act. ingr.

95% CL:

ca. 0 - ca. 4 292

Remarks on result:

other: calculated using probit analysis

Clinical signs:

other: The test article produced a significant level of dermal irritation in all animals at all dose levels which was characterized by eschar formation at the treatment sites vithin 24 hours after dosing. The 552 mg/kg treatment group exhibited no clinical sympt

Gross pathology:

Gross necropsy findings were minimal. There was an increased incidence of pale kidneys in animals at the highest treatment level as compared to controls. By contrast, the pale lungs in one control animal not replicated in any treatment group. Distended atria and/or ventricles were also noted in three animals at the highest dose level. These qualitative changes of the cardiac muscle would probably have gone unnoticed except for the specific requirements of the test protocol. One animal in the 3328 mg/kg bw treatment group was noted to have a heavily pigmented gel in the large intestine.

Results

Treatment	Doses	Mortality
		Males	Females	Combined
10% v/v ethanol /water	5.56 mL/kg	0/5	0/5	0/10
Test substance	552 mg/kg bw	0/5	0/5	0/10
	1104 mg/kg bw	0/5	0/5	0/10
	3328 mg/kg bw	3/5	2/5	5/10
	4448 mg/kg bw	5/5	3/5	8/10

Probit analysis

Treatment	Calculations	LD50
		Males	Females	Combined
Test substance	LD50 (mg/kg bw) with 95% confidence interval slope	a	3861	3342
		a	a	0-4292
		a	a	a

a = could not be reliably calculated using probit analysis method

Conclusion

The acute dermal toxicity of  test substance was evaluated in the rabbit model. The acute dermal LD50 (combined sexes) of this material was  determined to be 3342 mg/kg bw. The test material was clearly corrosive to the skin at the site of application at all dose levels. Systemically, the test material only elicited a moderate toxicity by the dermal route as reflected by its LD50. At dose levels needed to induce any significant level of toxemia by this route of exposure, primary clinical findings with any apparent relationship to dosing regimen included reduced fecal production, weight loss, emaciation and death. It is reasonable to conclude that these events were probably a conseqoence of a reduced food intake (a variable not measured in this study), with increasing levels of distress in the test populations and only an indirect effect of the test material. The cause of deaths in the test populations is not immediately obvious from the results of the study. While physical symptoms of decreased activity were universally present at the two highest dose levels and exhibited a dose response between 1104 mg/kg (10%) and 3328 mg/kg (100%), other adverse physical symptoms of prostration, ataxia, tremors, labored breathing and mucoid excretions were randomly distribüted among distressed animals. No clear correlation between symptoms and death were immediately evident. Necropsy f indings did not permit labeling any specific target organ. The noted anomalies to the cardiac muscle would have little signficance and would probably have gone unnoticed except  for the specific requirements of the test protocol. Although an increased incidence of pale kidneys vas also noted at the highest dose level, the significance of the observation is difficult to assess. Since mucoid excretions and pale kidneys were observed in different animals, a clear association of these events with renal toxicity cannot be stated with any degree of certainty. However, the delayed onset of convulsive seizures in one animal yould be commensurate with toxic manifestations of a renal failure. Neverthel ess, the renal observations could equally have been the consequence of postmortem changes and an artifact of delayed necropsy. Finally, the random isolated cl inical observati ons reported are probably experimental artifacts and unrelated to dosing regimens. Respiratory infections in laboratory rabbit populations are not uncommon and nasal discharge in a fey animals of the test popula tion probably reflects this condition. Since f stains of the haircoat and anogenital areas were observed primarily in dead animals, these effects are probably a result of postmortem events. The apparent cause of bloody snouts in a few animals is not immediately evident, particularly in the absence of any significant pathology to the respiratory system. The effect, however, may have arisen as a consequence of contact with residues of the test material at the dosing site. Therefore, the test substabce is corrosive to the skin at dose levels as low as 552 mg/kg. the material is only moderately toxic systemically by the dermal route as reflected by the established LD50 3342 mg/kg bw. Although the immediate cause of death f rom acute dermal exposure to test substance cannot be stated with certainty, the absence of  clinical symptoms and pathological evidence of cardiac toxicity negates the cardiac muscle as a primary target organ of test substance by this route of exposure.

Conclusions:

Under the study conditions, the acute dermal LD50 in rabbits for the test substance was determined to be 3342 mg/kg bw

Executive summary:

A study was conducetd to determine the acute dermal toxicity in rabbits of the test substance, DDAC (80% active in hydroalcoholic solution) according to the EPA guideline, in compliance with GLP. Five animals per sex per group were treated topically with test substance at 552, 1104, 3328 and 4448 mg/kg body weight. The dose volume administered to the animals was adjusted based on the stated activity of the substance to achieve the specified treatment levels. A control group, also consisting of five animals per sex, was administered the vehicle (a 10% v/v solution of non-denatured ethanol/water) at a dose volume of 5.56 ml/kg. The animals were observed for mortality and toxic effects continuously for 8 h after dosing and daily thereafter on days Individual body weights were determined on days 1, 8 and 15, or at death. At study termination, surviving animals were sacrificed and subjected to a gross necropsy examination. Animals Which died during the study were subjected to a gross necropsy examination at the time of death, or when found dead. The test substance was corrosive to the skin at all dose levels with evidence of eschar of within 24 h after dosing. By contrast, test substance was only moderately toxic systemically by the dermal exposure as reflected by the established LD50 of 3342 mg/kg (combined sexes). Although corrosive to the skin at 552 mg/kg, no manifest symptoms of toxicity were evident at this dose level. At the higher dose levels, there was a progressive increase in the incidence and severity of clinical symptoms. Primary clinical findings with any regimen included reduced fecal production, weight loss, emaciation and death. It is reasonable to conclude that these events were a probable consequence of reduced food intake with increasing levels distress in the test populations. The symptoms preceding death would then only reflect an indirect effect of the test substance. The cause of deaths in the test populations was not immediately evident from the test results. While the physical symptom of decreased activity was present in all animals at the two highest dose levels, other adverse symptoms of prostration, ataxia, tremors, labored breathing and mucoid excretions vere randomly distributed among distressed animals. No correlation between symptoms and death was immediately evident. Necropsy findings were minimal and did not permit the identification of a probable target organ responsible for the noted clinical profile or contributory to observed fatalities. The noted anomalies to the cardiac muscle yould have little significance and the qualitative changes would probably have gone unnoticed except for the specific requirements of the test protocol. The increased incidence of pale kidneys at the highest dose level is difficult to assess. Since mucoid excretions and pale kidneys were observed in different animals, an association of these events with renal toxicity cannot be stated with certainty. The delayed onset convulsive seizures in one animal at the highest dose level would be commensurate with toxic manfestations of a renal failure. However, the renal observations could equally have been the result of post-mortem changes and an artifact of delayed necropsy. Under these conditions, no immediate explanation for the noted convulsive seizures is possible. The remaining isolated clinical observations and necropsy findings can be attributed to experimental artifacts and/or preexisting conditions in the test populations unrelated to the dosing regimen. Therefore, the test substance is corrosive to dermal tissue and only moderately toxic by the dermal route. The cause of its toxic and lethal effects are not immediately evident from the test results. However, clinical symptoms and pathological evidence ofcardiac toxicity were not observed and the cardiac muscle did not appear to be a primary target organ after dermal exposure to test substance. Under the study conditions, the acute dermal LD50 in rabbits for the test substance was determined to be 3342 mg/kg bw (SIB, 1987).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

3 342 mg/kg bw

Quality of whole database:

Guideline compliant study

Additional information

Oral   

 

An acute oral toxicity study was performed in Wistar rats according to OECD Guideline 401, in accordance with GLP. The test substance was orally gavaged once to 5 males and 5 female rats per group at doses of 250, 500 and 1000 mg a.i./kg bw. The post-exposure period was 14 days. The examinations performed included mortality, body weight, clinical signs and gross necropsy for any macroscopic abnormalities. The mortality incidence in both sexes combined for high, mid and low dose groups were 10/10, 9/10 and 2/10. Necropsy of the decedents revealed mainly haemorrhages/red areas in glandular stomach or forestomach, discolouration of the stomach or intestinal content, irregular areas in the forestomach and adherence of spleen, pancreas, serosa of the forestomach, left lateral liver lobe and diaphragm to each other. Animals that survived to the end of the study showed similar effects. The oral LD50 of the test substance in Wistar rats were determined to be 406 and 264 mg a.i./kg bw in males and females respectively. The combined oral LD50 was determined to be 329 mg a.i./kg bw in males and females (RCC, 1990).   

 

In a second OECD 401 Guideline compliant study, groups of 5 male rats were orally gavaged with the test substance at the equivalent of 416, 520 and 728 mg a.i./kg bw and 5 female rats were gavaged at 728 mg a.i./kg bw. The animals were observed for clinical signs, mortality and body weight for 14 days. At the end of the study, surviving animals were sacrificed and a gross pathological examination was performed. Mortality was observed at 728 mg a.i./kg bw in males and females. Apart from unspecific symptoms, the animals showed impaired activity and irregular respiration. Additionally, narrow palpebral fissures, blood-encrusted lid margins, blood-encrusted snouts and swollen abdomen were observed. The clinical signs were resolved by Day 13. Development of body weight was retrograde in the first week and reversible by the end of the study. Animals that died during the course of the study showed discoloration of liver and lung, reddish fluid in the abdominal cavity, reddish mucus in intestine and corrosive lesions in the stomach. Animals sacrificed at the end of the observation period showed fusion of stomach with connective tissues. The oral LD50 of the test substance in male Wistar rats was determined to be in the range of 416 - 728 mg a.i./kg bw (Hoechst, 1991).      

 

Dermal    

 

In an OECD 402 Guideline compliant study, five male and five female rats received a dermal dose of 1000 mg a.i./kg bw for 24 h (dose volume: 10 mL/kg in distilled water) under occlusive dressing for 24 h. One day before exposure (Day -1), an area of approximately 5 x 7 cm2on the back of the animal was clipped and the test substance was applied. Twenty four hours later, dressings and residual test substance was removed using a tissue moistened with tap water. Animals were subjected to daily observations and weekly determination of body weight. Macroscopic examination was performed after terminal sacrifice on Day 15. No mortality occurred. Effects noted were lethargy in all animals between Days 2 and 4 and swelling, redness, erythema and necrosis of the skin. The majority of the skin effects persisted until the end of the observation period. No abnormalities were found at macroscopic post-mortem examination. Effects were limited to local irritation/corrosion of the skin, without involvement of systemic toxicity. The acute dermal LD50 of the test substance was determined to be > 1000 mg a.i./kg bw (NOTOX, 1996).     

 

A study was conducted to determine the acute dermal toxicity in rabbits of the test substance (80% active in hydroalcoholic solution) according to EPA guidelines, in compliance with GLP. Five animals per sex per group were treated topically with test substance at 552, 1104, 3328 and 4448 mg/kg body weight. The dose volume administered to the animals was adjusted based on the stated activity of the substance to achieve the specified treatment levels. A control group, also consisting of five animals per sex, was administered the vehicle (a 10% v/v solution of non-denatured ethanol/water) at a dose volume of 5.56 ml/kg. The animals were observed for mortality and toxic effects continuously for 8 h after dosing and daily thereafter. Individual body weights were determined on Days 1, 8 and 15, or at death. At study termination, surviving animals were sacrificed and subjected to a gross necropsy examination. Animals which died during the study were subjected to a gross necropsy examination at the time of death, or when found dead. The test substance was corrosive to the skin at all dose levels with evidence of eschar of within 24 h after dosing. By contrast, test substance was only moderately toxic systemically by the dermal exposure as reflected by the established LD50 of 3342 mg/kg (combined sexes). Although corrosive to the skin at 552 mg/kg, no manifest symptoms of toxicity were evident at this dose level. At the higher dose levels, there was a progressive increase in the incidence and severity of clinical symptoms. Primary clinical findings with any regimen included reduced faecal production, weight loss, emaciation and death. It is reasonable to conclude that these events were a probable consequence of reduced food intake with increasing levels distress in the test populations. The symptoms preceding death would then only reflect an indirect effect of the test substance. The cause of deaths in the test populations was not immediately evident from the test results. While the physical symptom of decreased activity was present in all animals at the two highest dose levels, other adverse symptoms of prostration, ataxia, tremors, laboured breathing and mucoid excretions were randomly distributed among distressed animals. No correlation between symptoms and death was immediately evident. Necropsy findings were minimal and did not permit the identification of a probable target organ responsible for the noted clinical profile or contributory to observed fatalities. The noted anomalies to the cardiac muscle would have little significance and the qualitative changes would probably have gone unnoticed except for the specific requirements of the test protocol. The increased incidence of pale kidneys at the highest dose level is difficult to assess. Since mucoid excretions and pale kidneys were observed in different animals, an association of these events with renal toxicity cannot be stated with certainty. The delayed onset convulsive seizures in one animal at the highest dose level would be commensurate with toxic manifestations of a renal failure. However, the renal observations could equally have been the result of post-mortem changes and an artifact of delayed necropsy. Under these conditions, no immediate explanation for the noted convulsive seizures is possible. The remaining isolated clinical observations and necropsy findings can be attributed to experimental artifacts and/or pre-existing conditions in the test populations unrelated to the dosing regimen. Therefore, the test substance is corrosive to dermal tissue and only moderately toxic by the dermal route. The cause of its toxic and lethal effects were not immediately evident from the test results. However, clinical symptoms and pathological evidence of cardiac toxicity were not observed and the cardiac muscle did not appear to be a primary target organ after dermal exposure to test substance. Under the study conditions, the acute dermal LD50 in rabbits for the test substance was determined to be 3342 mg/kg bw (equivalent to 2674 mg a.i./kg bw) (Siglin, 1987).  

 

In general, as quaternary ammonium compounds do not easily pass biological membranes, dermal absorption of these compounds is very limited. The dermal toxicity of aqueous DDAC solutions is related to its corrosivity and therefore more linked to the concentration of the administered solution than to the actual amount in mg/kg. Due to the direct corrosive effect, there is danger of irreversible damage to the skin upon exposure to the undiluted solution. Further, toxicity is secondary to the local tissue damage, rather than the result of percutaneously absorbed material. Some reviews mention comparable dermal LD50 data in rat from literature which is in the range of 2000 – 3000 mg/kg bw. 

 

Inhalation    

 

DDAC is not volatile and industrial production and formulation does not lead to the formation of inhalable aerosols. Inhalation exposure is therefore not expected to occur under conditions of normal and foreseeable handling and use, so that additional testing for acute inhalation toxicity is not considered necessary. Moreover, because of the corrosive nature of the substance, required risk reduction measures are in place. Finally, in case of spraying applications, the use of spray nozzles creating a coarse spray with droplet sizes ≥ 40 µm is recommended. Coarse sprays with droplets ≥ 40 µm are not inhalable by humans (EN 481 and WHO classification droplet sizes).  

 

Furthermore, there is no concern for aspiration hazard. Indeed, DDAC does not consist of aliphatic, alicyclic and aromatic hydrocarbons. Also, available information on typical solutions indicates that kinematic viscosity would be around 22.1 x 10-4m2/s at 20°C. Viscosity is not likely to decrease significantly with heating of the solution to 40°C, therefore viscosity is not expected to reach 7 x 10-6 m2/sec at 40°C and no classification for aspiration hazard is required. 

Justification for classification or non-classification

The lowest acute oral LD50 of the test substance in Wistar rats was determined to be 238 mg/kg bw, which supports a classification as Acute Tox. 3 - H301 (Toxic if swallowed) according to EU CLP (Regulation EC/1272/2008) criteria. In addition, the marketed forms of the test substance may trigger a STOT Single Exp. 3 - H336 (May cause drowsiness or dizziness) mixture classification,when the level of isopropanol exceeds the general concentration limit of ≥20%, according to EU CLP (Regulation EC/1272/2008) criteria.

The acute dermal LD50 of the test substance in rabbits was determined to be 3342 mg/kg bw (equivalent to 2674 mg a.i./kg bw). Due to the corrosivity nature of aqueous DDAC solutions, dermal toxicity is considered to be secondary to local tissue damage rather than the result of percutaneously absorbed material. Hence, no classification for acute dermal toxicity is warranted according to EU CLP (Regulation EC/1272/2008) criteria.