Phthalic anhydride

Endpoint summary

Description of key information

In a guinea pig maximisation test (GPMT) and several other tests including LLNAs (local lymph node assays) phthalic anhydride showed sensitizing properties.

In several animal experiments the respiratory sensitizing potential of phthalic anhydride was obvious. This finding is confirmed by occupational studies in humans.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: No solvent control, details of the reading not given, number of animals not given, poor documentation

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Principles of method if other than guideline:

Guinea pigs were treated by a series of 6 intradermal injections in the shoulder region to induce sensitization. After 6-8 days, sensitization was boosted by a 48 h occluded patch placed over the injection site. 12-14 days later, the animals were challenged on the flank by a 24 h occluded patch at the maximum non-irritant concentration. Challenge sites were scored for erythema and edema 24 and 48 h after removal of the patches

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Published study (1992). At this time an OECD guideline for a LLNA was not available.

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

not specified

Details on test animals and environmental conditions:

no data

Route:

intradermal

Vehicle:

other: acetone /polyethylene glycol 400 = 70:30

Concentration / amount:

induction injection: 0.1%
induction patch: 25%
challenge patch: 10%

Route:

epicutaneous, occlusive

Vehicle:

other: acetone /polyethylene glycol 400 = 70:30

Concentration / amount:

induction injection: 0.1%
induction patch: 25%
challenge patch: 10%

No. of animals per dose:

no data

Details on study design:

1st application: Induction 0.1 % intracutaneous
2nd application: Induction 25 % occlusive epicutaneous
3rd application: Challenge 10 % occlusive epicutaneous

Reading:

other: Not specified

Group:

test chemical

Dose level:

Not specified

Remarks on result:

other: 90 % of the tested guinea pigs were judged to be positive. Classification: extreme sensitizing (no further details given)

Reading:

other: Not specified

Group:

negative control

Remarks on result:

other: Dextran, 10% in challenge experiment

Reading:

other: Not specified

Group:

positive control

Remarks on result:

other: m-Aminophenol, 5% in challenge

90 % of the tested guinea pigs were judged to be positive. Classification: extreme sensitizing (no further details given).

Interpretation of results:

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

Executive summary:

Guinea pigs were treated by a series of 6 intradermal injections in the shoulder region to induce sensitization. After 6-8 days, sensitization was boosted by a 48 h occluded patch placed over the injection site. 12-14 days later, the animals were challenged on the flank by a 24 h occluded patch at the maximum non-irritant concentration. Challenge sites were scored for erythema and edema 24 and 48 h after removal of the patches. 90% of the animals were judged to be positive, resulting in the overall assessment of extremely sensitizing.

Reference 2

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: No GLP, test similar to OECD TG 429, dpm/node not given

Qualifier:

equivalent or similar to guideline

Guideline:

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

Principles of method if other than guideline:

The test substance was assayed at 3 consecutive concentrations from the following range: 100, 50, 25, 10, 5, 2.5, 1.0, 0.5, 0.25, 0.1, 0.05, and 0.01%. Groups of 4 mice were treated by a daily topical application of 25 µl of each concentration on the dorsal surface of each ear for 3 consecutive days. Control mice were treated with the vehicle alone. 4-5 days after the first topical application, all mice were injected intravenously through the tail vein with 250 µl phosphate buffered saline containing [³H]methyl thymidine (³HTdR; 20 µCi). After 5 h the mice were killed and the draining auricular lymph nodes were excised and pooled for each experimental group. ³HTdR incorporation was measured by ß-scintillation counting.

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

male/female

Details on test animals and environmental conditions:

CBA/Ca mice were used at the age of 8-12 wks

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

100, 50, 25, 10, 5, 2.5, 1.0, 0.5, 0.25, 0.1, 0.05, and 0.01%.

No. of animals per dose:

4

Parameter:

SI

Remarks on result:

other: no data

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Ratio of test to control lymphocyte proliferation (exposure period: 4 hours): 2.5%: 26 5%: 21.5 10%: 20,9

Sensitizer

Interpretation of results:

Category 1 (skin sensitising) based on GHS criteria

Executive summary:

A LLNA was performed. The test substance was assayed at 3 consecutive concentrations from the following range: 100, 50, 25, 10, 5, 2.5, 1.0, 0.5, 0.25, 0.1, 0.05, and 0.01%. groups of 4 mice were treated by a daily topical application of 25 µl of each concentration on the dorsal surface of each ear for 3 consecutive days. control mice were treated with the vehicle alone. 4-5 days after the first topical application, all mice were injected intravenously through the tail vein with 250 µl phosphate buffered saline containing [³H]methyl thymidine (³HTdR; 20 µCi). After 5 h the mice were killed and the draining auricular lymph nodes were excised and pooled for each experimental group. ³HTdR incorporation was measured by ß-scintillation counting.

Result: phthalic anhydride is positive in the LLNA

Reference: Basketter, 1992

Reference 3

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Limited documentation, 3 animals / dose, pretreatment with 1% of SDS

Principles of method if other than guideline:

To examine the sensitizing capacity of low molecular weight chemicals, a murine local lymph node assay (LLNA) was used. The sensitizing capacity of known allergens was quantified by dose-response modeling. at a stimulatory index (SI) of 3, the corresponding estimated concentration was calculated (EC3)

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

Balb/c

Sex:

male/female

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

0.25, 1, 2.5, 10, and 25%

No. of animals per dose:

3

Parameter:

SI

Remarks on result:

other: 3

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: the [³H]TdR incorporation is expressed per animal, i.e. the [³H]TdR incorporation is multiplied by the cell number of the 2 lymph nodes and divided by the cell number in culture

EC3 value: 0.357%
Phthalic anhydride was judged as extreme sensitizer.

Interpretation of results:

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

Executive summary:

To examine the sensitizing capacity of low molecular weight chemicals, a murine local lymph node assay (LLNA) was used. The sensitizing capacity of known allergens was quantified by dose-response modeling. At a stimulatory index (SI) of 3, the corresponding estimated concentration was calculated (EC3)

EC3 value: 0.357% - Phthalic anhydride was judged as extreme sensitizer.

Reference: van Och, 2000

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

In several animal experiments the sensitizing potential of phthalic anhydride was obvious. This finding is confirmed by occupational studies in humans.

In the study of Basketter (1992) Guinea pigs were treated by a series of 6 intradermal injections in the shoulder region to induce sensitization. After 6-8 days, sensitization was boosted by a 48 h occluded patch placed over the injection site. 12-14 days later, the animals were challenged on the flank by a 24 h occluded patch at the maximum non-irritant concentration. Challenge sites were scored for erythema and edema 24 and 48 h after removal of the patches. 90% of the animals were judged to be positive, resulting in the overall assessment of extremely sensitizing.

Respiratory sensitisation

Link to relevant study records

Reference

Endpoint:

respiratory sensitisation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: no GLP

Principles of method if other than guideline:

Guinea pigs were exposed through inhalation to phthalic anhydride (PA) dust at 0.5, 1.0, and 5.0 mg/m³, 3 hours/day for 5 consecutive days. Inhalation challenge with aerosolized phthalic anhydride-guinea pig serum albumin (PA-GPSA) was performed.

GLP compliance:

no

Species:

guinea pig

Strain:

Hartley

Sex:

female

Route of induction exposure:

inhalation

Route of challenge exposure:

inhalation

Vehicle:

unchanged (no vehicle)

Concentration:

0.5, 1.0, and 5.0 mg/m³

No. of animals per dose:

8 animals were exposed to 0.5 or 1.0 mg/m³
16 animals were exposed to 5.0 mg/m³

Results:

Inhalation challenge with phthalic anhydride dust. Changes in respiratory rate were not significantly greater than the changes in respiratory rate measured in air control animals challenged with phthalic anhydride dust.
The decrease noted in plethysmograph pressure changes was not different from those measurements taken from air control animals exposed to the same concentration of phthalic anhydride dust.
Inhalation challenge with PA-GPSA conjugate One animal in the 0.5 mg/m3 group and four animals in the 5 mg/m3 group experienced significant and sustained increases in respiratory rate on challenge, as compared with the air control animals. The same animal in the 0.5 mg/m3 group, one animal in the 1 mg/m3 group, and three animals (two with significant increases in rate) in the 5.0 mg/m3 group experienced sustained respiratory reactions that resulted in significant increases in plethysmograph pressure, as compared with the air control animals.
ELISA Linear regression analysis showed a highly significant dose-response relationship (p < 0.001) for IgG antibody. Phthalic anhydride dust exposure level: Mean O.D. (±SE) at 1/100 serum dilution Air contr: 0.048 ± 0.008 0.5 mg/m3: 0.230 ± 0.071 1.0 mg/m3: 0.298 ± 0.024 5.0 mg/m3: 0.692 ± 0.1061 PCA Animals with IgG1a and IgE antibody to PA-GPSA 0.5 mg/m3: 3/8; 0/8 1.0 mg/m3: 1/8; 0/8 5.0 mg/m3: 5/8; 0/8 5.0 mg/m3: (challenged with phthalic anhydride) 1/8ND Thirty-eight percent (3 of 8) of the animals in the 0.5 mg/m3 group had measurable circulating IgG1a antibody in serum. Of these three animals, one had a significant respiratory reaction on inhalation challenge with conjugate. One of eight animals (13%) in the 1.0 mg/m3 exposure group had IgG1a antibody; this same animal had significant respiratory reactivity on conjugate challenge. Sixty-three percent (5 of 8) of the animals in the 5.0 mg/m3 exposure group had allergic antibody. All five animals experienced respiratory reactivity on conjugate challenge. None of the study animals had detectable IgE antibody to PA-GPSA. Histopathology and antibody titers Foci were observed in 8 of 8 animals in the PA dust-exposed and challenged group, with 3 of 8 having 189 foci or more (individual scores: 11, 6, 1, 365, 14, 2, 331, 189, mean value 15; mean value control group: 1). One or two lung foci were noted in 5 of 8 filtered air control/PA dust-challenged guinea pigs. No indication of hemorrhage or inflammation was noted. Alveolar hemorrhage, with accumulation of red blood cells, and a few alveolar macrophages were observed. Minimal type II cell hyperplasia was also noted.

Characterization of phthalic anhydride dust
phthalic anhydride dust exposure level: Mean analytical concentration (mg/m3); MMAD (µm)
0.5 mg/m3: 0.55; 3.12 +/- 2.02
1.0 mg/m3: 1.27; 3.26 +/- 2.02
5.0 mg/m3: 5.57; 3.91 +/- 2.

Interpretation of results:

sensitising

Executive summary:

Guinea pigs were exposed through inhalation to phthalic anhydride (PA) dust at 0.5, 1.0, and 5.0 mg/m³, 3 hours/day for 5 consecutive days. Inhalation challenge with aerosolized phthalic anhydride-guinea pig serum albumin (PA-GPSA)

was performed.

Animals exposed to and challenged with 5.0 mg/m³ PA dust had significant numbers of hemorrhagic lung foci. Those animals with the greatest numberof foci had high IgG antibody activity to PA, measured by ELISA.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

In several animal experiments the respiratory sensitizing potential of phthalic anhydride was obvious. This finding is confirmed by occupational studies in humans

Guinea pigs were exposed through inhalation to phthalic anhydride dust at up to 5.0 mg/m³. Inhalation challenge with aerosolized phthalic anhydride-guinea pig serum albumin (PA-GPSA) conjugates elicited immediate onset respiratory reactions in animals exposed to all 3 levels of dust. Inhalation challenge of a subgroup of animals with phthalic anhydride dust did not elicit an immediate response, as measured in respiratory frequency and plethysmograph pressure. Serologic studies showed that these animals had allergic IgG1a antibody to PA-GPSA. There was a dose-dependent increase in specific IgG antibody activity as measured by ELISA. Animals exposed to and challenged with 5.0 mg/m³ PA dust had significant numbers of hemorrhagic foci.

In the occupational exposure study of Wenfors et al. (1986) the average concentration of phthalic anhydride dust at the workplaces was given as 3-13 mg/m³, of which 40-46% was in the inspirable dust fraction. Out of 118 workers exposed occasionally to phthalic anhydride dust for 2 months or more, 28 (24%) suffered from work-related rhinitis, 13 (11%) from chronic productive bronchitis, and 21 (28%) from work-associated asthma. Three out of eleven asthmatics had a phthalic anhydride-positive skin test, and in two subjects the presence of antibodies was demonstrated.

Justification for classification or non-classification

According to the harmonised classification - Annex VI of Regulation (EC)No 1272/2008 (CLP regulation) phthalic anhydrid is classified as Skin Sens. 1 (H317) and Resp. Sens. 1 (H334).

Based on the available studies for skin sensitisation a classification as Skin Sens. 1A ( H317: May cause an allergic skin reaction) is proposed. The classification for respiratory sensitisation will be retained (Resp. Sens. 1 (H334)) as a sub-classification is not possible based on the available studies.