1,3-bis(1-isocyanato-1-methylethyl)benzene

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From Jul. 29, 1981 to Oct. 23, 1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Principles of method if other than guideline:

Method: Test material was applied epicutaneously to intact skin of guinea pigs during the induction, challenge and rechallenge phases and skin irritation was scored by the Draize system.

GLP compliance:

yes

Type of study:

Buehler test

Justification for non-LLNA method:

A valid Buhler study was available before REACH came into force, therefore no additional LLNA study was conducted.

Species:

guinea pig

Strain:

Hartley

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Elm Hill Breeding Laboratories, 71 Elm Street, Chelmsford, Massachusetts 01824
- Weight at study initiation: 327-498 g
- Housing: Individually housed in stainless steel cages with wire mesh floors
- Diet (e.g. ad libitum): Purina Guinea Pig Chow, ad libitum
- Water (e.g. ad libitum): Filtered tap water, ad libitum
- Acclimation period: 7 d


ENVIRONMENTAL CONDITIONS
- Air changes (per hr): 14/ h
- Photoperiod (hrs dark / hrs light): 12 h dark/12 h light


IN-LIFE DATES: From: Jul. 07, 1981 To: Sep. 10, 1981

Route:

epicutaneous, open

Vehicle:

olive oil

Concentration / amount:

- Primary skin irritation phase: 0 (control), 0.10, 0.05, 0.025, 0.0125 and 0.00625 % molar equivalents of test or positive control article (25 µL) in olive oil
- Induction phase: Single applications of 0.36 molar concentrations in olive oil (25 µL)
- Challenge and rechallenge phase: 0, 0.10, 0.05, 0.025, 0.0125 and 0.00625 % molar equivalents of test or positive control article (25µL) in olive oil

Route:

epicutaneous, open

Vehicle:

olive oil

Concentration / amount:

- Primary skin irritation phase: 0 (control), 0.10, 0.05, 0.025, 0.0125 and 0.00625 % molar equivalents of test or positive control article (25 µL) in olive oil
- Induction phase: Single applications of 0.36 molar concentrations in olive oil (25 µL)
- Challenge and rechallenge phase: 0, 0.10, 0.05, 0.025, 0.0125 and 0.00625 % molar equivalents of test or positive control article (25µL) in olive oil

No. of animals per dose:

Primary Skin Irritation Phase: 5 animals/dose
Induction phase: 10 animals/dose (two sites per animal)
Challenge Phase: 10 animals/dose

Details on study design:

RANGE FINDING TESTS:
- Five animals each were exposed to 25 µL of molar dilutions (0, 0.10, 0.05, 0.025, 0.0125, 0.00625 %) of either the test or positive control article in olive oil
- Route: Epicutaneous; no patch was applied

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: Single
- Test groups: Yes
- Control group: Yes, olive oil (vehicle control) and IPDI (positive control)
- Site: Flank to trunk along both sides of each animal
- Frequency of applications: Once
- Duration: 5 d
- Concentrations: 0.36 molar concentration


B. CHALLENGE EXPOSURE
- No. of exposures: Single
- Day(s) of challenge: 9 d
- Test groups: Yes
- Control group: Yes
- Site: Applied to untreated site, flank to trunk along both sides of each animal
- Concentrations: 25 µL of 0, 0.10, 0.05, 0.025, 0.0125 and 0.00625 % molar concentration
- Evaluation (hr after challenge): 28 and 48 h


OTHER:
Rechallenge Phase: 9 d after the initial challenge
Procedure: Same as challenge

Challenge controls:

Not applicable

Positive control substance(s):

yes

Remarks:

Isophorene diisocyanate (IPDI)

Positive control results:

- Primary skin irritation phase: At 24 h one male exhibited a grade 1 erythema at the dose levels of 0.1 %; one female exhibited a grade 2 erythema at 0.1 and 0.05 %, and a grade 1 erythema with 0, 0.025, 0.0125 and 0.00625 % (olive oil only). By 48 h, both grade 2 erythemas had decreased to a grade 1 and the site treated with olive oil returned to normal. All other test sites appeared normal.
- Induction phase: Exhibited grades of 1, 2 and 3 for erythema and no edema at 24-hour interval. Scores had decreased slightly but were considered comparable at the 48-h interval
- Challenge phase: Mean skin irritation scores were higher at challenge than at the skin irritation phase
- Rechallenge phase: Mean skin irritation scores were less or comparable at rechallenge than at the skin irritation phase

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.1 and 0.05 %

No. with + reactions:

10

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 0.1 and 0.05 %. No with. + reactions: 10.0. Total no. in groups: 10.0. Clinical observations: -.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.025 %

No. with + reactions:

7

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 0.025 %. No with. + reactions: 7.0. Total no. in groups: 10.0. Clinical observations: -.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.0125 %

No. with + reactions:

9

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 0.0125 %. No with. + reactions: 9.0. Total no. in groups: 10.0. Clinical observations: -.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.00625 %

No. with + reactions:

5

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 0.00625 %. No with. + reactions: 5.0. Total no. in groups: 10.0. Clinical observations: -.

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.1, 0.05, 0.025 and 0.0125 %

No. with + reactions:

10

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 0.1, 0.05, 0.025 and 0.0125 %. No with. + reactions: 10.0. Total no. in groups: 10.0. Clinical observations: -.

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.00625 %

No. with + reactions:

7

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 0.00625 %. No with. + reactions: 7.0. Total no. in groups: 10.0. Clinical observations: -.

Key result

Reading:

rechallenge

Hours after challenge:

24

Group:

test chemical

Dose level:

0.1, 0.05, 0.025, 0.0125 and 0.00625 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: Reading: rechallenge. . Hours after challenge: 24.0. Group: test group. Dose level: 0.1, 0.05, 0.025, 0.0125 and 0.00625 %. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: -.

Key result

Reading:

rechallenge

Hours after challenge:

48

Group:

test chemical

Dose level:

0.1, 0.05, 0.025, 0.0125 and 0.00625 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: Reading: rechallenge. . Hours after challenge: 48.0. Group: test group. Dose level: 0.1, 0.05, 0.025, 0.0125 and 0.00625 %. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: -.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

0.1, 0.05, 0.025, 0.0125%

No. with + reactions:

10

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: -

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

0.00625%

No. with + reactions:

8

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: -

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

0.1, 0.05, 0.025, 0.0125%

No. with + reactions:

10

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: -

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

0.00625%

No. with + reactions:

7

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: -

Key result

Reading:

rechallenge

Hours after challenge:

24

Group:

positive control

Dose level:

0.1%

No. with + reactions:

8

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: -

Key result

Reading:

rechallenge

Hours after challenge:

24

Group:

positive control

Dose level:

0.05

No. with + reactions:

7

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: -

Key result

Reading:

rechallenge

Hours after challenge:

24

Group:

positive control

Dose level:

0.025, 0.0125 and 0.00625%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: -

Key result

Reading:

rechallenge

Hours after challenge:

48

Group:

positive control

Dose level:

0.1%

No. with + reactions:

6

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: -

Key result

Reading:

rechallenge

Hours after challenge:

48

Group:

positive control

Dose level:

0.05

No. with + reactions:

5

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: -

Key result

Reading:

rechallenge

Hours after challenge:

48

Group:

positive control

Dose level:

0.025

No. with + reactions:

1

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: -

Key result

Reading:

rechallenge

Hours after challenge:

48

Group:

positive control

Dose level:

0.0125 and 0.00625%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

-

Remarks on result:

other: -

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0

No. with + reactions:

0

Total no. in group:

0

Clinical observations:

-

Remarks on result:

other: No data

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0

No. with + reactions:

0

Total no. in group:

0

Clinical observations:

-

Remarks on result:

other: No data

Key result

Reading:

rechallenge

Hours after challenge:

24

Group:

negative control

Dose level:

0

No. with + reactions:

0

Total no. in group:

0

Clinical observations:

-

Remarks on result:

other: no data

Key result

Reading:

rechallenge

Hours after challenge:

48

Group:

negative control

Dose level:

0

No. with + reactions:

0

Total no. in group:

0

Clinical observations:

-

Remarks on result:

other: No data

Results with test material:

- Primary skin irritation phase: Two females exhibited a grade 1 erythema with 0.1 %, only at the 24 h interval. One male exhibited grade 2 erythema with 0.1 % and grade 1 erythema with 0.05 % and 0.025 % at both 24 and 48 h intervals. No skin irritation was observed at concentrations of 0.0125 % or below.

- Induction Phase: Exhibited grades 2 and 3 for erythema and no edema at the 24 h interval. By the 48 h interval, scores for erythema were either 0, 1 or 2.

- Challenge Phase: Mean skin irritation scores for all concentrations were higher at challenge than at the primary skin irritation phase.

- Rechallenge Phase: Mean skin irritation data were considered to be less than or comparable to the mean primary skin irritation phase

Table 1: Mean Skin Irritation Scores

Primary Skin Irritation Phase:
Concentration	0.1		0.05				0.025			0.0125			0.00625		0.0*
	Er	Ed	Er	Ed			Er		Ed	Er		Ed	Er	Ed	Er	Ed
IPDI (24 h)	0.6	0.0	0.4	0.0			0.2		0.0	0.2		0.0	0.2	0.0	0.2	0.0
IPDI (48 h)	0.2	0.0	0.2	0.0			0.2		0.0	0.2		0.0	0.2	0.0	0.0	0.0
11583B15 (24 h)	0.8	0.0	0.2	0.0			0.2		0.0	0.0		0.0	0.0	0.0	0.0	0.0
11583B15 (48 h)	0.4	0.0	0.2	0.0			0.2		0.0	0.0		0.0	0.0	0.0	0.0	0.0
Challenge Phase:
IPDI (24 h)	2.7	0.5	2.1		0.0	1.5		0.0		1.1	0.0		0.9	0.0	0.0	0.0
IPDI (48 h)	1.9	0.0	1.9		0.0	1.7		0.0		1.2	0.0		0.9	0.0	0.0	0.0
11583B15 (24 h)	2.3	0.2	2.1		0.2	0.7		0.0		1.1	0.0		0.5	0.0	0.0	0.0
11583B15 (48 h)	2.1	0.0	2.0		0.0	1.0		0.0		1.2	0.0		0.8	0.0	0.2	0.0
Rechallenge Phase:
A-IPDI (24 h)	0.9	0.0	0.8		0.0	0.0		0.0		0.1	0.0		0.0	0.0	0.0	0.0
A-IPDI (48 h)	0.7	0.0	0.6		0.0	0.1		0.0		0.0	0.0		0.0	0.0	0.0	0.0
B-IPDI (24 h)	0.5	0.0	0.3		0.0	0.1		0.0		0.0	0.0		0.0	0.0	0.0	0.0
B-IPDI (48 h)	0.4	0.0	0.1		0.0	0.0		0.0		0.0	0.0		0.0	0.0	0.0	0.0
11583B15 (24 h)	0.0	0.0	0.0		0.0	0.0		0.0		0.0	0.0		0.0	0.0	0.0	0.0
11583B15 (48 h)	0.0	0.0	0.0		0.0	0.0		0.0		0.0	0.0		0.0	0.0	0.0	0.0

 

A - Animals treated with IPDI during induction

B- Animals treated with 11583B15 during induction

* -Vehicle (olive oil) only

Er - Erythema

Ed - Edema

Interpretation of results:

Category 1A (indication of significant skin sensitising potential) based on GHS criteria

Conclusions:

Under the test conditions, the test material was considered to be a contact sensitizer in guinea pig.

Executive summary:

A study was conducted to assess the dermal contact sensitization potential of the test substance in guinea pig according to a Buehler protocol, in compliance with GLP. Test substance and isophorene diisocyanate (positive control substance) at concentrations of 0, 0.10, 0.05, 0.025, 0.0125 and 0.00625% were applied epicutaneously (non-occluded) to the intact skin of guinea pigs. Prior to the induction application, the primary irritation potential was determined. Challenge and rechallenge were performed 5 and 14 days after a single induction application, respectively. Clinical signs and body weight were recorded during the study and necropsies were conducted on animals at termination. Evidence of dermal contact sensitization including skin reactions were observed at sites treated with non-irritating concentrations and enhanced skin reactions were seen at sites treated with irritating concentrations. Contact sensitization was evident for both substances at initial challenge (5 day post-induction). Evidence of sensitization for both substances was negligible upon rechallenge (14 day post-induction). Under the study conditions, the test substance was considered to be a contact sensitizer in guinea pig (Calkins, 1981).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

A study was conducted to assess the dermal contact sensitization potential of the test substance in guinea pig according to a Buehler protocol, in compliance with GLP. Test substance and isophorene diisocyanate (positive control substance) at concentrations of 0, 0.10, 0.05, 0.025, 0.0125 and 0.00625% were applied epicutaneously (non-occluded) to the intact skin of guinea pigs. Prior to the induction application, the primary irritation potential was determined. Challenge and rechallenge were performed 5 and 14 days after a single induction application, respectively. Clinical signs and body weight were recorded during the study and necropsies were conducted on animals at termination. Evidence of dermal contact sensitization including skin reactions were observed at sites treated with non-irritating concentrations and enhanced skin reactions were seen at sites treated with irritating concentrations. Contact sensitization was evident for both substances at initial challenge (5 day post-induction). Evidence of sensitization for both substances was negligible upon rechallenge (14 day post-induction). Under the test conditions, the test substance was considered to be a contact sensitizer in guinea pig (Calkins, 1981).

Respiratory sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

respiratory sensitisation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From Jun. 02, 1987 to Dec. 08, 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Reason / purpose for cross-reference:

reference to other study

Principles of method if other than guideline:

The animals were initially exposed to the test material by the inhalation route (induction exposure). Following a rest period of 10-14 d during which an immune response may develop, the animals were exposed to a challenge dose (inhalation). The extent and degree of reaction to the challenge exposure in the test animals was compared with that demonstrated by control animals which underwent the same treatment during induction and received the challenge exposure.

GLP compliance:

yes

Remarks:

according to Toxic Substance Control Act (TSCA) GLP

Species:

guinea pig

Strain:

Hartley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hazleton Dutchland, Inc., Denver PA
- Housing: one animal per cage in stainless steel wire-mesh cages (23.5 x 40 x 18 cm)
- Diet: Pellet feed (Pro Lab Guinea Pig Diet, Agway, Inc.Delmont, PA), ad libitum, withheld during exposure
- Water: Tap water (Municipal Authority of Westmoreland Country. Greensburg, PA), ad libitum, withheld during exposure
- Acclimation period: 10 d

ENVIRONMENTAL CONDITIONS
- Photoperiod: 12h dark/12h light
- Temperature: 19.4-21.1 °C (67-70 °F)
- Relative humidity: 48-58%

Route of induction exposure:

inhalation

Route of challenge exposure:

inhalation

Vehicle:

unchanged (no vehicle)

Concentration:

- Induction phase: 30 µg/L TMXDI aerosol
- Challenge phase: 15-20 µg/L GPSA, followed by 15-20 µg/L aerosol of TMXDI-GPSA

No. of animals per dose:

Test group: 12; Control: 8

Details on study design:

MAIN STUDY
A. INDUCTION EXPOSURE
- Exposure period: 3 h
- Test groups: One (twelve animals)
- Control group: One (Eight animals, exposed to filtered air only)
- Frequency of applications: 3h/d for 5 d
- Duration: 5d
- Concentrations: 30 µg/mL TMXDI aerosol
- Induction exposure chamber description:
- Exposure chamber: Stainless steel, with glass windows for observation;
- Volume of the chamber: 900 L
- Air flow rate: 300 L/min
- Induction exposure cage dimensions: 17.5 x 24 x 18 cm wire mesh cages
- Frequency of data recording: Temperature and relative humidity were recorded 6 times/exposure
- Mean daily temperature: test group: 22 °C; control: 24°C



B. CHALLENGE EXPOSURE
- Day(s) of challenge: On Day 22, 23 and 26
- Exposure period: Animals breathed room air for a period of 20 min, followed by 20 min exposure to an aerosol of GPSA and then exposure to TMXDI-GPSA aerosol for a period of 20 min.
- Test groups: One (Twelve animals)
- Control group: One (Eight animals)
- Concentrations: 15-20 µg/L aerosol of GPSA, followed by a 15-20 µg/L aerosol of TMXDI-GPSA after a recovery period of 30 min
- Mean chamber concentration:
- Challenge exposure chamber description:
- Exposure chamber: Four whole body plethysmographs attached to a 2.5 L glass primary chamber
- Air flow rate: 20 L/min
- Acclimatization in chamber: 10-15 min
- Other: A Statham PM 15ETC differential pressure transducer was used to sense pressure changes created during inspiration and expiration of the animals; Frequency of data recording: 15 sec

OTHER:
- Animals assignment: Randomly
- Frequency of observation: Daily

Challenge controls:

None

Positive control substance(s):

none

Negative control substance(s):

none

Results:

(a) Chamber exposure concentrations:
- The mean induction chamber atmosphere concentration: 31.4±2.78 µg/L (by HPLC) and 30.5±3.15 µg/L (by gravimetric analysis); Mean analytical to nominal concentration ratio ranged between 0.39 -0.49; and mean MMAD of TMXDI aerosol: 1.9 µ with a mean GSD of 2.4.
- Challenge chamber concentration: Mean of individual animals was 17.48±2.21 µg/L for GPSA and 15.04±2.26 µg/L (after adjusting for salt content) for TMXDI-GPSA. The mass median aerodynamic diameter (MMAD) for GPSA representative of exposures was 3.6 µ with GSD of 5.75. (Refer to Table 1 under ‘Attached background material’ for details.)
(b) Clinical observations and mortality:
- Animals exhibited periocular, perinasal, and perioral wetness during and immediately following induction exposures.
- The respiration of these animals decreased and became forced during and following induction exposures. Few animals also displayed audible breathing and/or decreased motor activity during the induction exposure period.
- Mortality: Two animals died during the week of induction exposures (Day 2) and two animals died in the time period following these exposures (Day 19 and 25).
(Refer to Table 2 and 3, under ‘Attached background material’ for details)
(c) Body weights: (Refer to Figure 1 under ‘Attached background material’)
- During the period of the induction exposure, body weight loss was not significant.
- Following induction exposures, body weight gain was noted on Day 12, 19, and 26.
(d) Respiratory rate:
- During the inhalation challenge, none of the animals displayed an increase in respiratory rate greater than 36% of their pre-exposure rate (defined evidence of hypersensitivity. In some cases the pulmonary hypersensitivity criteria were met but they were later found out to be due to animal movements.
(e) Antibody analysis:
- TMXDI-treated guinea pigs had low, but positive titers following the induction exposures.
- Control guinea pigs displayed negative antibody titers.
- The dosing of animals could not be increased in order to increase the antibody titers, since mortality occurred in four out of the twelve exposed animals.
(f) Pathologic evaluation:
- Greater incidence of alveolar histiocytosis was observed in the lungs of the TMXDI-exposed guinea pigs in comparison to control. Further atelectasis was observed in the lungs of both sacrificed and found dead guinea pigs.
- Microscopic examination of the two guinea pigs showed pulmonary edema (one animal), and hyaline membrane formation along with pneumonitis, congestion and hemorrhage. (Refer to Table 4-12 under ‘Attached background material’)

Positive control results:

Not applicable

Negative control results:

Not applicable

Interpretation of results:

GHS criteria not met

Conclusions:

Under the test conditions, the test material was found to be non-sensitising.

Executive summary:

A study was conducted to assess the respiratory sensitization potential of the test substance in guinea pigs, in compliance with GLP. A group of 12 female Hartley guinea pigs were exposed for 5 successive days, 3 h/day by inhalation at a target concentration of 30 µg/L. A second, untreated group of eight animals served as control. The animals were challenged by inhalation during a 20 min exposure on Days 22, 23 and 26 (two weeks following induction exposure) with guinea pig serum albumin (GPSA) and TMXDI-GPSA (after a recovery period of 30 min) at concentrations of 15-20 µg/L. The pulmonary response of the animals to challenge was monitored by recording respiratory rates during and following challenge. Clinical signs of periocular, perioral and perinasal wetness were observed along with respiratory difficulties and diminished motor activity in TMXDI-exposed animals. Four of the twelve TMXDI-exposed animals died during the study. Histopathologic examination of the lungs of TMXDI-exposed animals surviving until the end of the study showed a greater incidence and degree of alveolar histiocytosis than the lungs of control animals. A pulmonary hypersensitivity response was defined as a sustained increase (> 36%) over the mean pre-exposure rate. An immediate pulmonary hypersensitivity response measured in terms of increased respiratory rates was not elicited from any of the guinea pigs upon inhalation challenge. Low, but positive antibody titers for TMXDI were observed in exposed guinea pigs. Hence, under the study conditions, the test substance was found to be non-sensitising (Burleigh-Flayer, 1988).

Reference 2

Endpoint:

respiratory sensitisation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From Oct. 25, 1983 to Dec. 03, 1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Reason / purpose for cross-reference:

reference to other study

Principles of method if other than guideline:

The animals were initially exposed to the test material by the inhalation route (induction exposure). Following a rest period of 10-14 d (induction period) during which an immune response may develop, the animals were exposed to a challenge dose (inhalation and/or intradermal injection). The extent and degree of reaction to the challenge exposure in the test animals was compared with that demonstrated by control animals which underwent the same treatment during induction and received the challenge exposure.

GLP compliance:

yes

Species:

guinea pig

Strain:

other: English smooth-haired guinea pigs (Cavia porcellus)

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hilltop Laboratory Animals, Scottdale, Pennsylvania
- Age at study initiation: 4-5 wK
- Weight at study initiation: 250-275 g
- Housing: Shoebox-type cages
- Diet: Purina Guinea Pig Chow No. 5025, ad libitum
- Water: Tap water, ad libitum
- Acclimation period: At least 12 d

Route of induction exposure:

inhalation

Route of challenge exposure:

other: Inhalation and intradermal routes

Vehicle:

other: Guinea pig serum albumin (GPSA)

Concentration:

Induction phase: 36 µg/L
Challenge phase (Inhalation): Guinea pig serum albumin (GPSA) at concentrations of 15-20 µg/L
Challenge phase (Intradermal): 100 µL GPSA (0.0333 %)

No. of animals per dose:

Twelve

Details on study design:

RANGE FINDING TESTS: Chamber concentrations in the induction phase were based on the results of a 5-day range-finding study

MAIN STUDY

A. INDUCTION EXPOSURE
- No. of exposures: 5
- Exposure period: 3 h
- Test groups: 1
- Control group: 1
- Frequency of applications: Once a day
- Duration: 3 h
- Induction phase target chamber concentrations: 36 µg/L
- Other: The animals were acclimated in the restraint tubes for periods of up to 1 h for up to 3 d prior to the first challenge exposure on study Day 22

B. CHALLENGE EXPOSURE- Inhalation-AC-005-guinea pig serum albumin (GPSA)
- No. of exposures: 3
- Day(s) of challenge: 3: On Day 22, 23 and 26
- Exposure period: 20 min
- Test groups: 1
- Control group: 1
- Concentrations: 0.015 to 0.020 mg/L

C. CHALLENGE EXPOSURE- Intradermal-AC-005-guinea pig serum albumin (GPSA)
- No. of exposures: 1
- Day(s) of challenge: 1: On Day 24
- Concentrations: 0.0333 %
- Dose volume: 100 µL
- Evaluation (hr after challenge): 6, 22 and 46 h
- Intradermal route was selected to assist immediate hypersensitivity

Challenge controls:

Control animals received AC-005-GPSA

Positive control substance(s):

none

Negative control substance(s):

none

Results:

Particle size analysis: Mass median diameter (and geometric standard deviation) was calculated to be 1.6 (2.4)
Clinical signs: Lethargy and nasal and oral discharge were observed during the induction exposures. There were no other treatment-related clinical abnormalities.
Body weights: Group mean body weight of animals remained similar to that controls.
Respiratory rates: None of the animals showed an increase in respiratory rate equal to or greater than the value 36 % used as a threshold as evidence of a positive response. There was therefore, no evidence of sensitization.
Lung weights: There were no treatment-related effects revealed in the lung weight data
Gross and histopathology: Pulmonary changes were not seen in guinea pigs
Skin Sensitization: The incidence and intensity of any erythemal or edemal reactions were similar in test and control animals. There was therefore no evidence of sensitization or cross-sensitization as evidenced by the absence of scores equal to or greater than 2 for erythema

Positive control results:

Not applicable

Negative control results:

Not applicable

Interpretation of results:

GHS criteria not met

Conclusions:

Under the test conditions, the test material was found to be non-sensitizing in guinea-pig.

Executive summary:

A study was conducted to assess the respiratory sensitization potential of the test substance in guinea pigs, in compliance with GLP. A group of 12 female English smooth-haired guinea pigs were exposed for 5 successive days, 3 h/day by inhalation at a target concentration of 36 µg/L. A second, untreated group of animals served as control. The animals were challenged by inhalation during a 20 min exposure on Days 22, 23 and 26 with AC-005-guinea pig serum albumin (GPSA) at concentrations of 15 to 20 µg/L. The pulmonary response of the animals to challenge was monitored by recording respiratory rates during and following challenge. The animals were challenged intradermally with AC-005-GPSA, on Day 24, and the skin response was assessed after 6, 22 and 46 h. Clinical signs and body weights were recorded during the study and necropsies were conducted on animals at termination. Lungs were weighed at termination and examined histologically. Lethargy as well as nasal and oral discharge were observed in treated groups during the induction exposures. Body weights, lung weights and the histological appearance of the lungs of animals remained comparable with those of the controls. Intradermal and respiratory challenges with test substance did not elicit any response indicative of sensitization. Under the study conditions, the test substance was found to be non-sensitizing in guinea-pig (Collins, 1984).

Reference 3

Endpoint:

respiratory sensitisation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From Sep. 20, 1983 to Oct. 28, 1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Principles of method if other than guideline:

Guinea pigs were exposed to test material by inhalation followed by intradermal challenge and the skin response was assessed after 24 and 48 h.

GLP compliance:

not specified

Species:

guinea pig

Strain:

other: English smooth-haired guinea pigs (Cavia porcellus)

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hilltop Laboratory Animals, Scottdale, Pennsylvania
- Age at study initiation: 4-5 wK
- Weight at study initiation: 250-275 g
- Housing: Shoebox-type cages
- Diet: Purina Guinea Pig Chow No. 5025, ad libitum
- Water: Tap water, ad libitum
- Acclimation period: At least 27 d

Route of induction exposure:

inhalation

Route of challenge exposure:

other: Inhalation and intradermal routes

Vehicle:

other: Guinea pig serum albumin

Concentration:

Treatment group: 24 µg/L
Naive Challenge Control group: Guinea Pig Serum Albumin (GPSA) at concentrations of 0.015 to 0.020 mg/L
Challenge phase: 25 µL (0.225 or 0.0225 %) administered intradermally

No. of animals per dose:

Eight

Details on study design:

MAIN STUDY

A. INDUCTION PHASE
- No. of exposures: 5
- Exposure period: 3 h
- Test groups: 1
- Control group: 1
- Frequency of applications: Once a day
- Days of exposure: Day 1-5
- Induction phase target chamber concentrations: 24 µg/L

B. CHALLENGE EXPOSURE (INTRADERMAL)
- No. of exposures: 1
- Concentrations: 0.225 or 0.0225 %
- Dose volume: 25 µL
- Evaluation (hr after challenge): 24 and 48 h

C. NAIVE-CONTROL GROUP- Inhalation-AC-005-guinea pig serum albumin (GPSA)
- Exposure period: 20 min
- Test groups: 1
- Concentrations: 0.015 to 0.020 mg/L

Challenge controls:

Control animals received AC-005-GPSA

Positive control substance(s):

none

Negative control substance(s):

none

Results:

- Particle size analysis: Mass median diameter (and geometric standard deviation) was calculated to be 1.8 (2.5)
- Clinical signs: Labored respiration, coughing, lung congestion, swelling around the eyes and nasal discharge were observed during the induction exposures. There were no other treatment-related clinical abnormalities.
- Body weights: Group mean body weight gain during week 1 was less than controls.
- Respiratory rates: None of the animals showed an increase in respiratory rate
- Lung weights: There were no treatment-related effects revealed in the lung weight data
- Gross and histopathology: Treatment-related pulmonary changes were not seen
- Skin Sensitization: Marked redness observed at 0.225 %

Positive control results:

Not applicable

Negative control results:

Not applicable

Conclusions:

Under the test conditions, the concentration of the test material causing a 50% depression in respiratory rate (RD50) in guinea pig was determined to be >125.5 µg/L.

Executive summary:

A range-finding study was conducted to assess the sensitization potential of the test substance in guinea pig. A group of 8 female English smooth-haired guinea pigs were exposed to substance for 5 successive days, 3 h/day by inhalation at target concentration of 24 µg/L. A second, untreated group of animals served as control. The animals were challenged topically with AC-005 on Day 8 and the skin response was assessed after 24 and 48 h. Clinical signs and body weights were recorded during the study and necropsies were conducted on animals at termination. Lungs were weighed at termination and were examined histologically. No evidence of increase in respiratory rate was seen in controls. Laboured respiration and nasal oral discharge occurred in treated groups during the induction exposures. Slightly reduced body weights were observed. Lung weights and the histological appearance of the lungs of animals remained comparable with those of the controls. Slightly prominent bronchial and cervical lymph nodes were apparent macroscopically. Intradermal challenges with test substance elicited clear erythemal response compared with controls. Under the study conditions, the concentration of test substance causing a 50% depression in respiratory rate (RD50) in guinea pig was determined to be >125.5 µg/L (Collins, 1984).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

A range-finding study was conducted to assess the sensitization potential of the test substance in guinea pig. A group of 8 female English smooth-haired guinea pigs were exposed to substance for 5 successive days, 3 h/day by inhalation at target concentration of 24 µg/L. A second, untreated group of animals served as control. The animals were challenged topically with AC-005 on Day 8 and the skin response was assessed after 24 and 48 h. Clinical signs and body weights were recorded during the study and necropsies were conducted on animals at termination. Lungs were weighed at termination and were examined histologically. No evidence of increase in respiratory rate was seen in controls. Laboured respiration and nasal oral discharge occurred in treated groups during the induction exposures. Slightly reduced body weights were observed. Lung weights and the histological appearance of the lungs of animals remained comparable with those of the controls. Slightly prominent bronchial and cervical lymph nodes were apparent macroscopically. Intradermal challenges with test substance elicited clear erythemal response compared with controls. Under the study conditions, the concentration of test substance causing a 50% depression in respiratory rate (RD50) in guinea pig was determined to be >125.5 µg/L (Collins, 1984).

A study was conducted to assess the respiratory sensitization potential of the test substance in guinea pigs, in compliance with GLP. A group of 12 female English smooth-haired guinea pigs were exposed for 5 successive days, 3 h/day by inhalation at a target concentration of 36 µg/L. A second, untreated group of animals served as control. The animals were challenged by inhalation during a 20 min exposure on Days 22, 23 and 26 with AC-005-guinea pig serum albumin (GPSA) at concentrations of 15 to 20 µg/L. The pulmonary response of the animals to challenge was monitored by recording respiratory rates during and following challenge. The animals were challenged intradermally with AC-005-GPSA, on Day 24, and the skin response was assessed after 6, 22 and 46 h. Clinical signs and body weights were recorded during the study and necropsies were conducted on animals at termination. Lungs were weighed at termination and examined histologically. Lethargy as well as nasal and oral discharge were observed in treated groups during the induction exposures. Body weights, lung weights and the histological appearance of the lungs of animals remained comparable with those of the controls. Intradermal and respiratory challenges with test substance did not elicit any response indicative of sensitization. Under the study conditions, the test substance was found to be non-sensitizing in guinea-pig (Collins, 1984).

A study was conducted to assess the respiratory sensitization potential of the test substance in guinea pigs, in compliance with GLP. A group of 12 female Hartley guinea pigs were exposed for 5 successive days, 3 h/day by inhalation at a target concentration of 30 µg/L. A second, untreated group of eight animals served as control. The animals were challenged by inhalation during a 20 min exposure on Days 22, 23 and 26 (two weeks following induction exposure) with guinea pig serum albumin (GPSA) and TMXDI-GPSA (after a recovery period of 30 min) at concentrations of 15-20 µg/L. The pulmonary response of the animals to challenge was monitored by recording respiratory rates during and following challenge. Clinical signs of periocular, perioral and perinasal wetness were observed along with respiratory difficulties and diminished motor activity in TMXDI-exposed animals. Four of the twelve TMXDI-exposed animals died during the study. Histopathologic examination of the lungs of TMXDI-exposed animals surviving until the end of the study showed a greater incidence and degree of alveolar histiocytosis than the lungs of control animals. A pulmonary hypersensitivity response was defined as a sustained increase (> 36%) over the mean pre-exposure rate. An immediate pulmonary hypersensitivity response measured in terms of increased respiratory rates was not elicited from any of the guinea pigs upon inhalation challenge. Low, but positive antibody titers for TMXDI were observed in exposed guinea pigs. Hence, under the study conditions, the test substance was found to be non-sensitising (Burleigh-Flayer, 1988).

Justification for classification or non-classification

The results from a study in guinea pig indicate that m-TMXDI has skin sensitizing properties and qualifies for classification as Skin Sens. 1A - H317 (may cause an allergic skin reaction) according to CLP (EC 1272/2008) criteria.

Exposure to m-TMXDI produced no evidence of significant respiratory sensitization in the guinea pig. In employee serum antibody survey, no antibodies to m-TMXDI were detected in samples from 25 employees exposed to urethane project products and materials. However, in line with the integrated evaluation strategy for respiratory sensitization data of ECHA Guidance 7a (Figure R.7.3-2), classification as Resp. Sens. 1 – H334 (may cause allergy or asthma symptoms or breathing difficulties if inhaled) is proposed.