Glutaral

Endpoint summary

Description of key information

Valid acute toxicity data for the oral, dermal and inhalation route of exposure are available for glutaraldehyde 50% aqueous solution. The LD50/LC50 obtained from these studies were as follows:

- Acute oral toxicity (rat): LD50 = 77 mg/kg bw (pure glutaraldehyde)

- Acute dermal toxicity (rat): LD50 > 2000 mg/kg bw (50% glutaraldehyde)

- Acute inhalation toxicity (rat, 4 h exposure): 0.28 < LC50 < 0.39 mg/L air (50% glutaraldehyde)

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:

equivalent or similar to guideline

Guideline:

other: 1984 EPA Assessment Guideline 40 CFR Part 158

Qualifier:

equivalent or similar to guideline

Guideline:

other: EPA Health Effects Test Guideline 40 CFR Part 798

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Sprague-Dawley, Inc. (Indianopolis)
- Age at study initiation: 7 to 9 weeks
- Weight at study initiation: 166 - 267 gram
- Fasting period before study: overnight (approximately 18 hours)
- Housing: Up to 5 per cage (seperated by sex), with wire floors under which animal cage board was placed.
- Diet: Agway RMH3000 certified rodent Pellets. Ad libitum
- Water: Municipal. Ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.4 - 21.1 °C
- Humidity (%): 47 - 61%
- Photoperiod (hrs dark / hrs light):12 / 12

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

DOSE VOLUME APPLIED: The dose volume was adjusted according to bodyweight to give 1 mL of dose per 100 grams of rat bodyweight

Doses:

Male rats: 100, 200, 400 mg/kg bw
Female rats: 100, 141, 200 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Dosed rats were observed frequently for signs of toxicity on the first day day of the test and twice a day thereafter.
- Weights were recorded on the day of dosing and at 7 and 14 days after dosing and at death.
- After 14 days, all survivors were sacrificed. Necropsies were performed on all animal that died or that were sacrificed.

Statistics:

LD50 values were calculated by the Moving Average Methtod.

Sex:

male

Dose descriptor:

LD50

Effect level:

246 mg/kg bw

Based on:

test mat.

Sex:

female

Dose descriptor:

LD50

Effect level:

154 mg/kg bw

Based on:

test mat.

Remarks on result:

other: 77 mg/kg bw for pure glutaraldehyde

Sex:

male/female

Dose descriptor:

LD50

Effect level:

200 mg/kg bw

Based on:

test mat.

Mortality:

Males:
- 400 mg/kg bw: All animals died within 1 day
- 200 mg/kg bw: One rat died within 2 days. No further mortality occurred.
- 100 mg/kg bw: No mortality occurred.

Females:
- 200 mg/kg bw: Two rats died within 1 day and another Two within 2 days. One rat survived.
- 141 mg/kg bw: Two rats died within 1 day. No further mortality occurred.
- 100 mg/kg bw: No mortality occurred.

Clinical signs:

other: Sluggishness, lacrimation, piloerection, diarrhea, trace amount of blood in the urine of two rats, a red crust on the perinasal fur and a brown stain on the perineal fur (of 1 rat). Surviving rats recovered within 4 to 5 days.

Gross pathology:

Necropsy of the rats that died revealed red lunges, red to dark maroon stomachs (some hemorrhaged, 1 filled with red liquid), discolored intestines (yellow, red, brown or black), dark red kidneys (in 2 rats) and a small amount of blood in the urine of 1 rat. Gross pathologic evaluation of survivors revealed no remarkable gross lesions.

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

Acute oral toxicity (rat, female): LD50 = 77 mg/kg bw (pure glutaraldehyde)

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

77 mg/kg bw

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Scientifically acceptable, well-documented study. The conduct was similar to OECD 403 but no particle size analysis was undertaken. However, within a further similar acute inhalation study performed by the same author (see BASF83/59), a particle size analysis was conducted, which revealed that 100% of the test substance applied as liquid aerosol reached the lung alveoli.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Principles of method if other than guideline:

Ten male and ten female Sprague-Dawley rats per dose group were exposed to different concentrations of test material as liquid aerosol; the animals were subjected to a head-nose exposure for 4 hours. The exposure period was followed by an observation period of 14 days. During and after exposure, mortality and clinical signs of toxicity were recorded at regular time intervals. The body weight was determined prior test initiation and thereafter, on day 7 and day 14 post-exposure. Rats that died during the experiment were subjected to necropsy; those which survived were sacrificed at the end of the experiment and were also subjected to necropsy. An untreated rat collective served as control. The determination of the LC50 values was based on the Probit Analysis.

GLP compliance:

no

Remarks:

; GLP was not compulsory at the time the study was performed

Test type:

standard acute method

Limit test:

no

Specific details on test material used for the study:

- Name of test material (as cited in study report): Glutaraldehyde approx. 50% solution, poor in methanol
- Physical state: liquid
- Analytical purity: 50%
- Lot/batch No.: the test substance No. was 80/265
- Stability under test conditions: approx. 12 months

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

- Source: Willi Gassner, Sulzfeld, Germany (animal breeder)
- Age at study initiation: 8 weeks
- Mean body weight of the males at study initiation: 298 +/- 35 g
- Mean body weight of the females at study initiation: 224 +/- 28 g
- Housing: animals were housed in groups of five in wire cages of Becker, type D III, without bedding.
- Diet (e.g. ad libitum): SSNIFF R complete diet for rats and mice, supplied by SSNIFF-Versuchstierdiäten GmbH (Soest, FRG), ad libitum
- Water (e.g. ad libitum): Tap water ad libitum
- Temperature (°C): 22 +/- 2 °C
- Humidity (%): 55 +/- 5 %
- Photoperiod (hrs dark / hrs light): 12 h/ 12 h

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose/head only

Vehicle:

other: The test substance was offered to the animals as a liquid aerosol/air mixture

Details on inhalation exposure:

AEROSOL GENERATION, EXPOSURE SYSTEM AND PROCEDURE
- Constant amounts of test substance were supplied to a two-component atomizer by means of a metering pump;
- By means of compressed air (1.8 bar) a mixture of test substance and air (liquid aerosol) was generated, which was passed into the inhalation system;
- The inhalation system was a head-nose inhalation system INA 20, BASF AG, V ca. 55 l;
- By means of the exhaust air system the pressure ratios in the inhalation system were adjusted in such a way that the amount of fresh air was about 10% higher (excess pressure) . This ensured that the mixture of test substance and air was not diluted by laboratory air in the breathing zones of the animals.

AIR SAMPLING FOR ANALYSIS OF TEST MATERIAL CONCENTRATIONS, METHOD FOR ANALYTICAL VERIFICATION
- A sampling apparatus consisted of 2 impingers connected in series and a downstream fritted glass flask was used;
- The sampling sites were Inmediately adjacent to the animal noses;
- One sample per concentration group was collected every hour;
_ The sampling flow was 1.25 m/s, and the sample amount reached up to 50 litres;
- The analytical measurement of the test material concentrations in the collected samples was based on gas-chromatography.

PARTICLE SIZE ANALYSIS:
No particle size analysis was undertaken within the present study. However, within a further similar acute inhalation study performed by the same author (see BASF83/59), a particle size analysis was conducted, which revealed that 100% of the test substance applied as liquid aerosol reached the lung alveoli.

Analytical verification of test atmosphere concentrations:

yes

Remarks:

For details, see above

Duration of exposure:

4 h

Concentrations:

Nominal: 0.23, 0.41, 0.53, 0.68 and 0.9 mg/l
Measured: 0.10, 0.18, 0.28, 0.39 and 0.44 mg/l

No. of animals per sex per dose:

10 animals/sex/group

Control animals:

yes

Details on study design:

- The animals were subjected to a head-nose exposure for 4 hours; this was followed by an observation period of 14 days;
- The rats were observed during exposure and over a period of 14 days for mortality (daily) and clinical signs of toxicity (each workday
- Body weights were recorded at test initiation, after 7 days and at the end of the observation period;
- Animals that died during the observation period were subjected to necropsy and gross pathological examination,
- Animals that survived were sacrificed at the end of the exposure period by means of CO2 for necropsy and gross pathology.
- An untreated rat collective served as control.

Statistics:

The determination of the LC50 value was based on Probit Analysis according to Finney DJ, Cambridge University Press, 3rd edition, 1971.

Sex:

male/female

Dose descriptor:

LC50

Effect level:

0.28 - 0.39 mg/L air (analytical)

Exp. duration:

4 h

Sex:

male

Dose descriptor:

LC50

Effect level:

0.35 mg/L air (analytical)

95% CL:

0.3 - 0.39

Exp. duration:

4 h

Sex:

female

Dose descriptor:

LC50

Effect level:

0.28 mg/L air (analytical)

95% CL:

0.22 - 0.29

Exp. duration:

4 h

Mortality:

- in the control group, all animals survived;
- in the 0.18 mg/l air group, mortality was 4/20, i.e. 20%;
- in the 0.28 mg/l air group, mortality was 4/20, i.e. 20%;
- in the 0.39 mg/ l air group, mortality was 14/20, i.e. 70%;
- in the 0.44 mg/l air group, mortality was 19/20, i.e. 95%.

Clinical signs:

other: During the exposure period vigorous attempts to escape, wiping of the snout, lid closure, and aqueous or red discharge from eyes and noses were observed. During the post-exposure period whooping or gasping respiration with rasping sounds during inspiratio

Body weight:

After 7 days, the body weights of the treated males were clearly impaired compared to controls; After 14 days this impairment still was observed in the 0.28 and the 0.39 mg/l groups. For the females, the body weight in the 0.39 mg/l group was impaired during the whole observation period; the body weight of the 0.28 mg/l group only was affected after 7 days.

Gross pathology:

- Necropsy of the animals that died during the experiment revealed acute congestion, pronounced emphysema of the lungs as well as edematization and infarctoid hyperemia.
- Necropsy of the surviving animals, which were sacrificed at the end of the observation period, showed no pathological abnormalities.

Details on mortality:

Applied Test Con. (mg/l)	Mortality (males)	Mortality (females)	Mortality (both sex)
0.10	0/10	0/10	0/20 (0%)
0.18	1/10 (d14)*	3/10 (d1-d2)	4/20 (20%)
0.28	1/10 (d1)	3/10 (d2-d7)	4/20 (20%)
0.39	7/10 (4h-d2)	7/10 (4h-d2)	14/20 (70%)
0.44	9/10 (4h-d1)	10/10 (4h-d14)	19/20 (95%)

*, Time of death after dosing (h, hours; d, days)

Details on mean body weights/sex/group:

Applied Test Con. (mg/l)	Initially		After 7 days**		After 14 days**
	Males	Females	Males	Females	Males	Females
0*	307 g	230 g	340 g	240 g	367 g	249 g
0.10	289 g	228 g	324 g	238 g	376 g	252 g
0.18	304 g	224 g	319 g	238 g	360 g	246 g
0.28	305 g	222 g	320 g	228 g	343 g	240 g
0.39	287 g	211 g	316 g	211 g	321 g	208 g
0.44	304 g	232 g	285 g	168 g	334 g	-***

*, Control group of 90 animals/sex.

**, The mean body weight refers to the surviving rats.

***, No survivors.

Interpretation of results:

Category 2 based on GHS criteria

Conclusions:

- Acute inhalation toxicity (rat, 4 h exposure): 0.28 < LC50 < 0.39 mg/L air (50% glutaraldehyde)

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

280 mg/m³ air

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 September 1994 to 14 June 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 81-2 (Acute Dermal Toxicity)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Specific details on test material used for the study:

- Name of test material (as cited in study report): Glutaraldehyde, obtained from BASF Corporation
- Physical state: clear colorless liquid
- Analytical purity: 50.2%
- Composition of test material, percentage of components: 50.2% aqueous solution
- Lot/batch No.: V6-612

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hazleton Research Products, Inc., Denver, PA
- Age at study initiation: young adults were used
- Weight at study initiation: 2363 to 2521 g
- Housing: individually, in suspended mesh-bottom cages
- Diet (e.g. ad libitum): Purina Certified Rabbit Chow #5312, ad libitum
- Water (e.g. ad libitum): municipal water, ad libitum
- Acclimation period: at least 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-22 °C
- Humidity (%): 36-62%
- Photoperiod (hrs dark / hrs light): 12 h/12 h

REMARK:
- Analysis of feed was performed and provided by the manufacturer
- Analysis of water was performed according to Standard Operation Procedures (SOP)
- Contaminants were not present in animal feed or water at levels expected to interfere with the objectives of the study

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: intact clipped skin on the backs of the animals
- % coverage: the area covered was about 23% of the total body surface
- Type of wrap if used: the application site was covered with gauze binders, which were again secured by means of non-irritating adhesive tape. Each animal received a collar

REMOVAL OF TEST SUBSTANCE
- Washing: each application site was gently cleaned with lukewarm water
- Time after start of exposure: 24 hours

TEST MATERIAL
- The test material was dosed based on density (specific gravity). The dose volume was determined by dividing the dose level (g/kg) by the specific gravity (1.02 g/ml)
- The individual dose was determined on the basis of the body weight and a dose volume of 1.96 ml/kg bw; thus, the final test concentration was 2000 mg/kg bw

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

Five/sex/group

Control animals:

no

Details on study design:

The animals were observed for mortality (after the first 1, 3 and 4 hours, and twice a day thereafter until day 14), clinical signs of toxicity (after the first 1, 3 and 4 hours, and once a day thereafter until day 14) and local skin changes (after 30 to 60 minutes following removal of the dressing, and daily thereafter until day 14); body weights were recorded on day 0, 7 and 14. At the end of the observation period, the animals were sacrificed for the purpose of necropsy.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred.

Clinical signs:

other: Two males and one female showed mucoid feces on day 1 to 2 of treatment; one female showed wet brown urogenital staining about 4 hours after application. From day 3 of observation, no more signs of toxicity were seen and all animals appeared normal.

Gross pathology:

Necropsy revealed thickening and scabbing of the application sites in all animals. No further treatment-related abnormalities were reported.

Other findings:

Local skin changes:
The treatment resulted in severe erythema, moderate to severe edema and eschar with subsequent exfoliation in all animals. In 6 case, the application sites displayed signs of corrosion. Fissuring of the skin was seen in 9 cases after day 6, and on day 7, yellow staining and desquamation were seen in all animals. These severe signs of skin irritation persisted over the complete period of observation in all animals.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Additional information

Oral

Rat

In a study performed similar to OECD Guideline 401, glutaraldehyde (50% aqueous solution; 0.5% methanol) was given by oral gavage to male and female Sprague-Dawley rats. A LD50 of ca. 285 mg/kg bw (equivalent to 143 mg/kg bw active ingredient) was reported in female rats (BASF, 1994). BASF performed two additional studies investigating 25% glutaraldehyde (8% methanol). Both studies were performed similar to OECD guideline 401. The LD50 of 25% glutaraldehyde was determined to be 742 mg/kg bw (equivalent to 186 mg/kg bw active ingredient) (BASF, 1970) and 530 mg/kg bw (equivalent to 133 mg/kg bw active ingredient) (BASF, 1970).

In a publication by Ballantyne (1986, and 2001), reporting study results from three Bushy Run Research Center (BRRC) studies, male and female Wistar rats were exposed to 0.5, 1, 2, 5, 10, 15, 25, 45 and 50% glutaraldehyde (≥15% males only). Per concentration, volumes were altered to come up with a LD50 for the different concentrations. A reciprocal relationship between LD50 and dosage from dose concentrations exceeding 15% was observed. The reason for this effect of dilution on toxicity is not clear, but could be related to the fact that at higher concentrations there is severe irritancy and corrosivity to the upper alimentary tract and death may be a consequence of this. At lower concentrations, and lesser degrees of alimentary irritancy, then a greater proportion of glutaraldehyde may be absorbed and exert systemic toxicity. Recalculated to the LD50 of pure glutaraldehyde, the lowest LD50 was 66 mg/kg bw observed in females exposed to 5% glutaraldehyde. Ballantyne also investigated possible differential toxicity in acidic unbuffered glutaraldehyde and alkaline buffered glutaraldehyde. Both glutaraldehydes were found to have quite similar acute oral toxicity: 3450 and 4160 mg/kg bw for 2.2% unbuffered and buffered glutaraldehyde, respectively.

The BRRC performed two additional experiments. In the study from 1980, female Wistar rats were exposed to 50% glutaraldehyde and a LD50 of 1210 mg/kg bw was determined (605 mg/kg bw active ingredient). In the study from 1992 the toxicity of glutaraldehyde 50% (<0.1% methanol) was evaluated. This experiment was performed under GLP regulations and utilizing EPA guidelines based methods (40 CFR Part 798 and 40 CFR Part 158). Doses were varied through changes in concentration. The LD50 determined under the conditions of this study was 264 mg/kg bw for male rats, 154 mg/kg bw for female rats, and 200 mg/kg bw for male/female rats (132, 77, and 100 mg/kg bw, respectively for the active ingredient).

Glutaraldehyde was also investigated in several other studies. Smyth et al. (1962) exposed male Wistar rats to 25% glutaraldehyde. The original reported LD50 referring to the test substance was 2.38 mL/kg bw (2523 mg/kg bw; 631 mg/kg bw active ingredient). In a study by the Nutrition International inc. (1982) performed according to EPA 40 CFR 163.81 -1, male and female Wistar rats were exposed to 50% glutaraldehyde. The LD50 for 50% glutaraldehyde was determined to be 452 mg/kg bw (226 mg/kg bw active ingredient). The Mellon Institute (1964), exposed male Carworth Farms-Elias albino rats to 45% glutaraldehyde and the LD50 was determined to be 1.19 mL/kg bw (1329 mg/kg bw; 605 mg/kg bw active ingredient).

Mouse

Ballantyne (2001) exposed male and female mouse to 0.01, 0.05, 0.1, 1, 5, 25, or 50% glutaraldehyde. Per concentration volumes were altered to come up with a LD50 for the different concentrations. The studies in the mice are similar to the results observed in the rat that there was a reciprocal relationship between LD50 and dosage from dose concentrations exceeding 5%. Recalculated to the LD50 of pure glutaraldehyde, the lowest LD50 was 27 mg/kg bw observed in females exposed to 5% glutaraldehyde (hereby is taken into account that the LD50 in females at 0.1% is probably an outlier). In Ohsumi et al (1988) a LD50 of 1300 mg/kg bw was observed in mice exposed to 25% glutaraldehyde (325 mg/kg bw active ingredient).

Rabbit

Two studies in rabbits are available (BASF, 1975). In the first study performed in accordance with OECD Guideline 401 and GLP, rabbits were exposed to 25% glutaraldehyde (8% methanol) and a LD50 of 530 mg/kg bw was determined (133 mg/kg bw active ingredient). The aim of second study was to examine the liver function of treated animals under acute oral toxicity test conditions. The liver function as determined on the basis of the bromosulphthalein test (BST) and the determination of the serum transaminase (SGPT) was not impaired by the treatment with glutaraldehyde.

Conclusion

Several studies investigating the acute oral toxicity of glutaraldehyde are available. For rats the LD50 recalculated for pure glutaraldehyde ranges from 66 mg/kg bw to 605 mg/kg bw; in mice from 27 to 325 mg/kg bw and in rabbits a LD50 of 133 mg/kg bw was observed. Most of these studies were not performed according to guidelines and GLP. The lowest observed LD50 values was 27 mg/kg bw in mice (Ballatyne 2001). However, this study had limitations in reporting of methods and results. Therefore, the lowest LD50 obtained in a study following guidelines and according to GLP was selected as key: BRRC (1992) reporting a LD50 of 154 mg/kg bw (50% glutaraldehyde).

Dermal

Rabbit

In a study by WIL Research (1995), New Zealand White rabbits were exposed to 50% glutaraldehyde under semi-occlusive conditions for 24 hours. The test was performed in accordance with EPA OPP 81 -2 and in accordance with GLP. The necropsy revealed thickening and scabbing of the application sites in all animals. No further treatment-related abnormalities were reported. The LD50 was determined to be >2000 mg/kg bw.

Nutrition International Inc. performed two studies in rabbits testing 50% glutaraldehyde (1982). Both tests were performed in accordance with EPA 40 CFR 163.81-2. Male and female New Zealand White rabbits were exposed to 50% glutaraldehyde under occlusive conditions for 24 hours. In the first study, the LD50 was determined to be >5 mL/kg bw (>5650 mg/kg bw). In the second study it was determined that the LD50 was 16.5 mL/kg bw (18,645 mg/kg bw).

The Carnegie-Mellon Institute of Research performed two studies in rabbits testing 25% glutaraldehyde (1977). In the first study, male New Zealand White rabbits were exposed to 25% glutaraldehyde for 24 hours under occlusive conditions. The LD50 was determined to be 12.8 mL/kg bw (13,568 mg/kg bw). The study was repeated (1977) and the LD50 determined was determined to be 16 mL/kg bw (16,960 mg/kg bw).

The Mellon institute exposed New Zealand Whites to 45% glutaraldehyde under occlusive conditions for 24 hours and the LD50 was determined to be 628 mg/kg bw.

In a publication by Ballantyne (1986), male and female New Zealand Whites were exposed to 5, 10, 15, 25, 45 and 50% glutaraldehyde (5, 25 and 50% males only) under occlusive conditions for 24 hours. Per concentration, volumes were altered to come up with a LD50 for the different concentrations. For the dose concentrations 5 -15% no LD50 could be determined as this value was higher than the highest dose tested. The LD50 of the active ingredient exceeds 2100 mg/kg bw when rabbits were exposed to 25% glutaraldehyde. The LD50 of the active substance when exposed to 45% glutaraldehyde lies between 1004 and 1360 mg/kg bw and the the LD50 of the active substance when exposed to 50% glutaraldehyde lies between 898 and 1432 mg/kg bw. In addition, Ballantyne (1997) investigated possible differential in acidic unbuffered glutaraldehyde and alkaline buffered glutaraldehyde. Both glutaraldehydes were found to have quite similar acute dermal toxicity: >16000 mg/kg bw for both 2.2% unbuffered and buffered glutaraldehyde.

Rat

BASF performed an acute dermal toxicity study in male and female Sprague-Dawley rats with 50% glutaraldehyde (0.5% methanol). The study was performed similar to OECD guideline 402. Rabbits were exposed to 400, 1000, or 2000 mg/kg bw under occlusive conditions for 24 hours. The LD50 was determined to be >2000 mg/kg bw. In a study by Uemitsu et al. (1976), male and female Sprague-Dawley rats were exposed to undiluted 25% glutaraldehyde. The type of coverage and exposure time is unknown. The LD50 was determined to be >2500 mg/kg bw. The Bushy Run Research Center (1980) exposed female Wistar rats under occlusive conditions to 50% glutaraldehyde for 4 hours. The LD50 was determined to be 2780 mg/kg bw.

Mouse

In a study by Uemitsu et al. (1976), male and female ICR mice were exposed to undiluted 25% glutaraldehyde. The type of coverage and exposure time is unknown. The LD50 was determined to be >4500 and >5840 for male and female mice, respectively.

Conclusion

Tests performed in rats and mice indicate that the LD50 for dermal acute toxicity to 50% glutaraldehyde exceeds 2000 mg/kg bw. The test results in rabbits shows a more mixed picture with LD50 ranging from 628 to 18000 mg/kg bw for 50% glutaraldehyde. The dermal LD50 need not be corrected for 50% as concentrations above 50% will not be manufactured or used. The results by Ballatyne (1986) show that the effects were related to concentration instead of dosage applied. Therefore, toxicity is considered to be secondary to the corrosive properties of glutaraldehyde rather than a result of toxicity of the absorbed material. As the current guidelines require testing under semi-occlusive conditions, the results of the study testing under occlusive conditions are less reliable. Therefore, the study by WIL Research has been selected as key.

Inhalation

Rat: aerosol

BASF performed three acute inhalation toxicity studies similar to OECD guideline 403. Inhalable aerosols of glutaraldehyde are considerably toxic; mortalities of rats, which were head-nose exposed for 4 hours to 50% glutaraldehyde as liquid aerosol at concentrations of 0.10 to 0.44 mg/l resulted in an LC50 between 0.28 mg/L and 0.39 mg/L (BASF, 1994). In a second study performed under similar conditions a LC50 of 0.48 mg/L was determined (BASF, 2001). In this study a droplet size analysis showed that 100% of glutaraldehyde liquid aerosol (< 2.8 µm) reached the lung alveoles of treated rats. In a third study (BASF, 1985), male and female Wistar rats were exposed to an aerosol of 25% glutaraldehyde. Other test conditions were similar to the other two BASF studies. In this study a LC50 of 0.8 mg/L was observed. In another study, a 4 -hour exposure to an aerosol with an mean airborne concentration of 0.32 mg/L (100 %) did not produce mortality but caused slight reversible irritation of the ocular, buccal, and respiratory mucous membranes. Body weights and necropsy findings did not indicate test material effects (Hoechst, 1981).

Rat: vapour

BASF also performed three inhalation hazard tests. In the first test (BASF, 1994), male and female Sprague-Dawley rats were exposed to ca 15 mg/L of 50% glutaraldehyde (0.5% methanol) for 1 to 7 hours. Exposure for one hour resulted in no mortality, but after 3 hours 1 out of 12 animals died. After 7 hours all six animals were dead. In the two other studies (BASF, 1970 and BASF, 1970), male and female Sprague-Dawley rats were exposed to 25% glutaraldehyde (8% methanol) for 8 hours. The test concentrations were 12 and 40 mg/L, respectively. No mortality was observed in both studies.

Ballantyne and Myers (2001) reported data on acute vapor exposure studies with male and female Wistar rats. Tests were performed with vapor generated statically or dynamically at ambient temperature to produce near saturated vapor atmosphere. Tested glutaraldehyde concentrations ranged from 14.5 to 51% and the measured glutaraldehyde vapour concentration ranged from 3.0 to 48.1 ppm. Exposure time ranged from 4 to 8 hours. In none of the performed studies mortality was observed. In addition, Ballantyne (1997) investigated possible differential toxicity in acidic unbuffered glutaraldehyde and alkaline buffered glutaraldehyde. Both glutaraldehydes were found to have quite similar acute inhalation toxicity. No mortality was observed in both tests when male and female Sprague-Dawley rats were exposed to air saturated with vapour of 2% glutaraldehyde.

The Bushy Run Research Center (1984) exposed female Wistar rats to the vapour of 50% glutaraldehyde for 6 hours. The mean measured concentration was 4.9 ppm. No mortality was observed. The Mellon Institute (1964) exposed female Carworth Farms-Elias albino rats to the vapour of 45% glutaraldehyde for 8 hours. The concentration tested was 12.58 mg/L. No mortality was observed. Carnegie-Mellon Institute of Research (1977) exposed Wistar rats (sex unknown) to the saturated vapour of 25% glutaraldehyde for 8 hours (no information on concentration in air). The test was performed under static and dynamic conditions. In both tests no mortality was observed. Uetmitsu et al. (1976) exposed male and female Sprague-Dawley rats to a vapour of 25% glutaraldehyde for a maximum of 180 minutes. The concentration tested was 20 ppm (0.083 mg/L). The inhalation time resulting in 50% mortality was about 60 and 86 minutes for male and female rats, respectively.

Mouse: vapour

Zussi et al. (1994) exposed male Swiss mice to a vapour of 25% glutaraldehyde for 60 minutes. At 2.6 ppm a 50% decrease in respiratory rate was observed. Uemitsu et al. (1976) exposed male and female ICR mice to a vapour of 25% glutaraldehyde for a maximum of 120 minutes. The concentration tested was 20 ppm (0.083 mg/L). The inhalation time resulting in 50% mortality was about 51 and 94 minutes for male and female mice, respectively. Varpela et al (1971) exposed 10 male NMRi mice per group to 2% glutaraldehyde for 24 hours at concentrations of 33 and 133 µg/L. One case of mortality was seen at 33 µg/L. No other mortalities were observed.

Conclusion

Based on the available data it can be assumed that mortality after inhalation is predominantly caused by aerosol and not by vapour: the different inhalation hazard test shows that glutaraldehyde vapor is not the toxic component in glutaraldehyde atmosphere. Therefore, the study with the lowest observed LD50 after aerosol exposure has been selected as key.

Justification for selection of acute toxicity – oral endpoint
Several studies investigating the acute oral toxicity of glutaraldehyde are available. The lowest observed LD50 value from a study following guidelines has been chosen as key.

Justification for selection of acute toxicity – inhalation endpoint
Based on the available data it can be assumed that mortality after inhalation is predominantly caused by aerosol and not by vapour: the different inhalation hazard test shows that glutaraldehyde vapor is not the toxic component in glutaraldehyde atmosphere. Therefore the study with the lowest observed LD50 after aerosol exposure has been selected as key.

Justification for selection of acute toxicity – dermal endpoint
As the current guidelines require testing under semiocclusive conditions, the results of the study testing under occlusive conditions are less reliable. Therefore, the study by WIL Research has been selected as key.

Justification for classification or non-classification

Glutaraldehyde 50% aqueous solution is acute toxic when applied orally or by inhalation; in case of dermal contact, the main effect of glutaraldehyde is due to its corrosiveness, whereas systemic toxicity due to percutaneous absorption of the substance only plays a secondary role. According to Annex VI of EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 and based on the available data, glutaraldehyde has to be classified as Acute Tox 3: H301: Toxic if swallowed and Acute Tox 2: H330: Fatal if inhaled.