Aluminium tri-sec-butanolate

Endpoint summary

Description of key information

Upon contact with water or moisture (e.g. within mucous membranes) aluminium tri-sec-butanolate hydrolyses immediately to butan-2-ol and aluminium 3+ cations (as hydroxide and oxyhydroxide). Hence, toxicity is determined by the toxicity of these two species

The skin sensitization of butan-2 -ol was assessed in a guinea-pig maximization test and the challenge exposures did not induce any effects.

Basketter (1999) investigated the allergenic potential of a.o. aluminium chloride hexahydrate (5, 10 and 25% in petrolatum) in the Local Lymph Node Assay (LLNA). Groups of 4 CBA/Ca mice (7 to 12 weeks of age) were treated with 25 μL of substance or with an equal volume of the vehicle alone, on the dorsum of both ears. The mice were treated once daily for 3 days. Two days later, the mice were injected with 250 μL of phosphate buffered saline (PBS) with 20 μCi of tritiated thymidine (2 Ci mmol-l). The mice were killed 5 hours later and a single-cell suspension of lymph node cells was prepared by mechanical disaggregation. Aluminium chloride hexahydrate did not induce a lymph node proliferation response compared to concurrent vehicle-treated controls, and therefore the response was judged as negative. The results of this study add to the weight of evidence for a low sensitisation potential of aluminium 3+ cations.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

yes

Remarks:

:

GLP compliance:

no

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

not specified

Details on test animals and environmental conditions:

Species and strain: mouse, 4 CBA/Ca
Source: Harlan Olac, Bicester, UK.
Justification of species and strain: Mouse is the preferred animal for this test (OECD TG#429)
Sex: not stated
Body weight range at the beginning of the study: not stated
Age at testing: 7 to 12 weeks
No further details mentioned

Vehicle:

other: petrolatum

Concentration:

5.0%, 10.0%, and 25.0%

No. of animals per dose:

4

Details on study design:

Two days after the last exposure, the mice were injected with 250 µL of phosphate buffered saline (PBS) containing 20 µCi of tritiated thymidine (from Amersham International, Amersham, UK). Five hours later, the mice were killed, draining lymph nodes excised and a single-cell suspension of the pooled lymph node samples was prepared.

The lymph node cell suspension was washed in excess PBS, precipitated with 5% trichloroacetic acid (TCA) at 4 ºC for 18 hours. After resuspension in TCA, β-scintillation counting was used to measure tritium incorporation.

The method used to kill the animals was not reported.

Observations:
Proliferation of cells in the lymph nodes.

- A positive result was defined as a threefold or greater proliferation than in the concurrent vehicle treated controls.

Positive control substance(s):

other: positive results were seen for metal salts of gold, beryllium, cobalt, mercury, platinum and tin that were tested in parallel

Statistics:

NA

Positive control results:

positive responses were noted

Key result

Parameter:

SI

Value:

>= 0.7 - <= 0.8

Test group / Remarks:

5% 0.8; 10% 0.8; 25% 0.7

Parameter:

EC3

Remarks on result:

not determinable

Remarks:

all values SI values < 3

The results for aluminium chloride hexahydrate were negative. There was no information on the irritancy of the tested concentration from a pre-test

Interpretation of results:

GHS criteria not met

Conclusions:

Aluminium chloride hexahydrate did not show sensitizing potential under the conditions used in this assay.

Executive summary:

Basketter et al. (1999) investigated the allergenic potential of 13 metal salts including aluminium chloride hexahydrate (99% purity) in the Local Lymph Node Assay (LLNA). Groups of 4 CBA/Ca mice (7 to 12 weeks of age) were treated with 25 μL of substance or with an equal volume of the vehicle alone, on the dorsum of both ears. The mice were treated once daily for 3 days. Two days later, the mice were injected with 250 μL of phosphate buffered saline (PBS) with 20 μCi of tritiated thymidine (2 Ci mmol^-l). The mice were killed 5 hours later and a single-cell suspension of lymph node cells was prepared by mechanical disaggregation. A substance was considered a skin sensitizer the proliferation in the lymph nodes of treated mice was 3-fold or greater than that in the concurrent vehicle-treated controls. Aluminium chloride hexahydrate administered in petrolatum (vehicle) at test concentrations of 5.0%, 10.0% and 25.0% did not induce a lymph node proliferation response compared to concurrent vehicle-treated controls, and therefore the response was judged as negative. The results of this study add to the weight of evidence for a low sensitisation potential of aluminium 3+ cations.

Reference 2

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1986

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well documented, according to accepted guidelines.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

yes

Remarks:

-insignificant deviation (strain of test animals not reported)

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The information from a Maximisation test performed in 1986 is available and considered to be sufficienly reliable

Species:

guinea pig

Strain:

not specified

Sex:

male/female

Details on test animals and environmental conditions:

Guinea-pigs bought from a commercial supplier (Porcellus Ltd., U.K.) were used. The. gulnea-pigs had body weights in the range 300 - 370 g at the time they were received from the supplier. The animals were randomlsed into slngle sex groups of 1o animals and given an accllmatizatlon period of at least two weeks after which they were housed in groups of five animals (two and three per cage).Food and water was provided ad libitum and the temperature was maintained at 19 - 23 °C. A 12/12 hour light/dark cycle was maintained throughout the study.

Route:

intradermal and epicutaneous

Vehicle:

corn oil

Concentration / amount:

0.1% (intradermal induction)
50% (topical induction)
25% (topical challenge)

Route:

epicutaneous, occlusive

Vehicle:

corn oil

Concentration / amount:

0.1% (intradermal induction)
50% (topical induction)
25% (topical challenge)

No. of animals per dose:

10/sex (treatment group)
5/sex (control group)

Positive control substance(s):

no

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

25%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

None

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: None.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

25%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

None

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: None.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

25%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

None

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: None.

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

25%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

None

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: None.

The erythema resulting from the topical challenge was scored on a four point scale (0, 1, 2, 3) immediately on removal of the challenge patches and 24 and 48 hours later. None of the twenty test animals showed any positive response at either 24 or 48 hours after removal of the challenge patches. It is concluded, therefore, that the test material is not a skin sensitizer in guinea pigs.

Interpretation of results:

GHS criteria not met

Conclusions:

Skin sensitization potential of 2-butanol was negative.

Executive summary:

Under the conditions of this test none of the test animals showed a skin reaction during the challenge exposure. Thus the substance is not considered being sensitizing to skin.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

None of the hydrolysis products is expected to cause sensitization of the skin.

Respiratory sensitisation

Link to relevant study records

Reference

Endpoint:

respiratory sensitisation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2008

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Basic data given

Qualifier:

no guideline available

Principles of method if other than guideline:

Examination of the absolute and relative numbers of different cell types and specific biochemical parameters in fluid obtained from bronchoalveolar lavage of animal lungs (BALF) following either intratracheal or inhalation exposure to a substance can provide information on the nature of the reaction of the tissue, i.e the mechanism of action. This information is useful to support and interpret histopathological observations and/or external observations of respiratory symptoms or changes in lung function. In this study, histopathology and BALF analyses were done in the the presence and absence of ovalbumin, a known inducer of eosinophilic inflammation, in order to provide further information on the nature of the mechanism of action (allergenic versus non-specific irritative).

GLP compliance:

no

Species:

mouse

Strain:

ICR

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Japan, Inc. (Kanagawa, Japan)
- Age at study initiation: 5 weeks at arrival; 6 weeks at testing
- Weight at study initiation: 307-315 g
- Housing: Plastic cages placed in a “conventional” room. Bedding with soft wood chips not otherwise specified.
- Diet: commercial diet CE-2 obtained from CLEA Japan Inc., Tokyo, Japan.
- Water: ad libitum
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 °C
- Humidity (%): 55-70%
- Air changes (per hr): not reported
- Photoperiod (hrs dark / hrs light): Artificial light 12 hours daily from 6 a.m. to 6 p.m.

Justification of species and strain: ICR mice were chosen based on the results of an earlier study (Ichinose T et al., 2003; Toxicol Appl Pharmacol 187: 29-37) that showed that this species is “moderately” responsive to airway inflammation on exposure to OVA by intratracheal instillation (IT).

Route of induction exposure:

other: Intratracheal instillation

Route of challenge exposure:

other: not applicable

Vehicle:

other: Normal saline

Concentration:

Negative vehicle control (saline),
OVA alone,
Asian SD alone,
Arizona SD alone,
SiO2 alone,
Al2O3 alone,
Asian SD + OVA,
Arizona SD + OVA,
SiO2 + OVA,
Al2O3 + OVA.

Concentration: 0.1 mg per mouse

Deposition efficiencies were calculated using a tidal volume of 0.15 mL/mouse and a breathing rate of 200 breaths per minute. 0.1 mg/mouse was reported to be 111 times the weekly amount of particulate matter that would be deposited in the alveoli assuming 3% deposition (based on the ICRP model at 5.5 micron particle size) at an exposure level of 0.1 mg/m3.

No. of animals per dose:

16 animals/group
- 8 animals used for pathology and 8 animals for BALF analyses.

Details on study design:

Preparation of Test Solution:
In the absence of OVA, 5 mg of particulate was suspended in 2.5 or 5 mL of vehicle and sonicated for 5 minutes while being cooled (temperature not specified)
For the combined OVA and particulate exposure, the OVA (100µg) was dissolved in 10 mL or 5 mL of saline vehicle. 2.5 mL of the OVA solution was then mixed with 2.5 mL of the particle suspension.

Administration of Test Solution:
Volume: 0.1 mL
Method: The suspension was intratracheally administered under anaesthesia (4% halothane, Takeda Chemical, Osaka, Japan) using a polyethylene tube.
The animals were dosed 4 times in total. The interval between doses was 2 weeks.

Further Study details:
The animals were killed by exsanguination one day after the last intratracheal instillation when anaesthetised using an i.p. injection of pentobarbital. At this time, the animals were approximately 12 weeks of age.

Observations:
Pathology of Lung Tissue:
Pathologic examinations were done on the lung tissue from 8 out of 16 mice/group. The lungs were fixed with 10% neutral phosphate-buffered formalin, stained with haematoxylin and eosin (H&E) to assess infiltration of eosinophils and lymphocytes and also, to assess proliferation of goblet cells, periodic acid-shiff (PAS). The evaluation was done by two pathologists independently.

Bronchoalveolar fluid (BALF) analyses:
Cell counts:
The BALF of the remaining 8 mice was evaluated for cell counts. Slides were prepared using a Cytopsin (Sakura Co., Ltd., Tokyo, Japan) and were stained with Diff-Quik. 300 cells were counted.

Levels of cytokines:
The cytokines interleukin-5 (IL-5), IL-12, interferon-gamma (IFN-γ), tumour necrosis factor-alpha (TNF-α), macrophage inflammatory protein-1alpha (MIP-1α), IL-13, and eotaxin were measured using ELISA.

Levels of lactate dehydrogenase (LDH):
Measured using a lactate dehydrogenase C II-Test Wako from Wako Chemicals Ltd. (Osaka, Japan).

Antigen (OVA)-specific and total IgE and IgG1 antibodies:
The antibodies were measured using commercial ELISA kits.

Statistical Analyses:
Group differences were assessed using ANOVA and the Fisher’s projected least significant differences (P/SD) test.

Challenge controls:

Not applicable.

Positive control substance(s):

none

Negative control substance(s):

not specified

Results:

Pathology of Lung Tissue:
Al2O3:
The animals treated with aluminium oxide did not show a significantly increased proliferation of goblet cells or infiltration of lymphocytes when compared with the saline control.

Ovoalbumina (OVA ) + Al2O3:
Lymphocyte infiltration was higher in the OVA+Al2O3 group compared with the control (p<0.001), and also when compared with OVA alone (p<0.01) and with Al2O3 alone (p<0.001).

Eosinophil infiltration was higher in the OVA+Al2O3 group compared with the control (p<0.01) and also OVA+Al2O3 compared with Al2O3 alone (p<0.01).

Goblet cell proliferation was higher in the OVA+Al2O3 group compared with the control (p<0.001), OVA+Al2O3 compared with OVA alone (p<0.05) and also when compared with Al2O3 alone (p<0.001).

Among the groups exposed to the particulates alone, the greatest changes were observed in the SiO2-treated group. Among the groups treated with OVA+particulates, the greatest changes were observed in the OVA+SiO2 group followed by the OVA+Arizona SD group, the OVA+Asian SD group and last the OVA+Al2O3 group.

Bronchoalveolar Lavage Fluid (BALF):
Cell counts
Total cells:
Among the groups exposed to particulates alone, only the SiO2-treated group had levels significantly greater than the control.
In the combined exposure groups, OVA+Asian SD, OVA+Arizona SD, and OVA+SiO2 had levels greater than the control (p<0.001). Total cells in the OVA + Al2O3 group were also significantly greater than the control but not to the same extent (p<0.05). No groups had cell counts greater than that observed in the group with OVA alone. The highest numbers were observed in the OVA+SiO2 group.

Macrophages:
Among the groups exposed to particulates alone, only Arizona SD and SiO2 caused significant increases in macrophages compared with the control (p<0.01 and p<0.001, respectively).
Among the combined exposure groups, OVA + Asian SD, OVA + Arizona SD, and OVA + SiO2 showed levels greater than the control. Numbers of macrophages in the OVA + Al2O3 group were greater than the control but not to the same extent (p<0.01). Only OVA+Arizona SD and OVA+SiO2 had greater numbers of macrophages than the OVA alone group (p<0.05 and p<0.001, respectively).

Eosinophils:
Particulates alone:
No effects observed.
Combined exposures:
OVA+Al2O3Numbers of eosinophils in the OVA+Asian SD (p<0.05), the OVA+Arizona SD (p<0.001) and the OVA+SiO2 (p<0.001) were greater than in the controls. None showed levels greater than OVA alone.

Neutrophils:
Particulates alone:
The SiO2 group was significantly greater than the controls (p<0.001)

Combined exposures:
OVA+Al2O3
Lymphocytes:
Levels in the Arizona SD group were significantly greater than the controls (p<0.01).
OVA+Asian SD (p<0.05) and OVA+Arizona SD (p<0.001) were significantly greater than the OVA only group.

Cytokines
IL-5
Significant elevations were observed for OVA+Arizona SD and OVA+SiO2 compared to the control and compared to OVA alone.

IL-6
A significant elevation was observed for OVA+SiO2 compared to OVA alone.

IL-12
The SiO2 group had significantly higher levels than the control (p<0.001). The OVA+SiO2 group had significantly higher levels than the control (p<0.001), the OVA alone group (p<0.001), and the SiO2 alone group (p<0.001). Levels in the OVA+Arizona SD group were marginally significantly greater than the control group (p<0.05).

IL-13
The OVA+SiO2 group had significantly higher levels than the control (p<0.001), OVA alone (p<0.001), and SiO2 alone groups.

IFN-γ
Asian SD alone (p<0.01), Arizona SD alone (p<0.01), SiO2 alone (p<0.01) and Al2O3 alone (p<0.05) had significantly higher levels than the control.

TNF-α
The Asian SD group (p<0.01), the SiO2 group (p<0.01) and the Al2O3 group (p<0.05) had significantly higher levels than the control. In the combined exposures, OVA+Asian SD and OVA+Arizona SD had higher levels than the controls. None of the particulate-treated groups had levels significantly higher than the OVA alone group.

Levels of lactate dehydrogenase (LDH):
Control: 8.48±1.38 IU/L
Asian SD: 5.56±0.26 IU/L
Arizona SD: 8.19±1.05 IU/L
SiO2: 9.99±0.75 IU/L
Al2O3: 6.17±0.77 IU/L
OVA: 5.09±0.67 IU/L
OVA+Asian SD: 5.98±0.65 IU/L
OVA+Arizona SD: 7.35±1.11 IU/L
OVA+SiO2: 31.18±8.97 IU/L
OVA+Al2O3: 6.37±0.42 IU/L

For the chemokine eotaxin, significant elevations were observed only in the OVA+SiO2 group. KC (keratinocyte chemoattractant) was significantly elevated relative to the control in the Arizona SD (p<0.01) and SiO2 (p<0.001) groups. In the combined exposure groups, the OVA+Arizona SD and OVA+SiO2 groups were significantly elevated relative to both the controls and the OVA alone groups. Levels of monocyte chemotactic protein-3 (MCP-3) in the OVA+Arizona SD and OVA+SiO2 groups were also significantly elevated relative to the control and the OVA alone group. Macrophage inflammatory protein-1α was significantly elevated in the Arizona SD and SiO2 groups relative to the controls and in the OVA+SiO2 group relative to the OVA alone group. OVA+Asian SD, OVA+Arizona SD and OVA+SiO2 had levels significantly greater than the control.

Antigen (OVA)-specific and total IgE and IgG1 antibodies:
Serum levels of OVA specific IgG1 antibodies were significantly elevated relative to levels in the OVA group alone in animals treated with OVA+Arizona SD and OVA+SiO2 (p<0.001). No OVA-specific IgE antibodies were detected. Levels of total IgE in serum in the particulate-treated groups did not differ significantly from levels in the group treated with OVA alone.

Positive control results:

Not applicable.

Negative control results:

Not applicable.

Interpretation of results:

GHS criteria not met

Conclusions:

When co-administered with OVA, all the tested materials showed an increase in eosinophils on H&E stained slides (OVA+SiO2>OVA+Arizona SD>OVA+Asian SD>OVA+Al2O3). Considering the results for Al2O3, specifically, in BALF, Al2O3 alone did not lead to significant increases in total cells, macrophages, eosinophils, neutrophils or lymphocytes. When Al2O3 was administered with OVA, small but statistically significant increases in total cells (p<0.05), macrophages (p<0.01) and lymphocytes (p<0.05) were observed relative to the control but not relative to the OVA alone group. Significant (p<0.05) increases in IFN-γ and TNF-α relative to the saline control were observed in BALF of Al2O3 treated animals. IL-5, IL-6, IL-12 and IL-13 did not show significant increases in the Al2O3-treated animals. In exposures combined with OVA, the only significantly elevated cytokine was IFN-γ.

Overall, the results from the study showed that allergic inflammatory effects of atmospheric dusts are likely due to SiO2. Al2O3 was the least inflammatory material tested and led to only weak effects on the mouse lung.

Executive summary:

Ichinose et al. (2008) studied allergic inflammation after intratracheal instillation of Asian sand dust, sand dust, amorphous silica and Al₂O₃ in 6-week old male ICR mice. Four instillations were performed at 2-week intervals. There were ten groups of animals (n=16 in each). One of these groups received Al₂O₃ (particle size 1~5 µm), a dose of 0.1 mg suspended in saline. The control group received saline only (0.1 mL). The animals were killed one day after the last instillation. Eight out of 16 animals in each group were used for pathologic examination. The lung samples were stained with haematoxylin and eosin to evaluate the degree of infiltration of eosinophils or lymphocytes in the airways, and with periodic acid-shiff to evaluate the degree of proliferation of goblet cells in the bronchial epithelium. The other 8 mice were used for examination of free cell counts (total and differential), determination of levels of lactate dehydrogenase (LDH), cytokines (Interleukins – IL-5, IL-6, IL-12, IL-13, interferon-IFN-gand tumor necrosis factor- TNF-a) and chemokines in bronchoalveolar lavage fluids (BALF), and also total IgE in serum using enzyme-linked immunosorbent assays (ELISA). In the group of mice exposed to Al₂O₃, the levels of eosinophil and lymphocyte infiltration in the submucosa and proliferation of goblet cells in the airways, the level of LDH, chemokines and interleukins, number of cells in BALF and the level of IgE in serum were not significantly different from those in the control mice. The results suggest that intratracheal administration of Al₂O₃ does not produce allergic inflammatory effects in the lungs of mice.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

There are no indications that Al2O3 induces respiratory sensitization

Justification for classification or non-classification

Based on the outcome of the studies with both hydrolysis products of aluminium tri-sec-butanolate, the substance has not to be classified for sensitizing properties according to Regulation EC 1272/2008.