Nitrilotrimethylenetris(phosphonic acid)

Endpoint summary

Description of key information

In the key skin sensitisation study, conducted according to a protocol similar to OECD Test Guideline 406 but not in compliance with GLP, ATMP-H (CAS 6419-19-8; EC 229-146-5; without information on active acid content) was not sensitising to the skin of guinea pigs (Henkel, 1984, Reliability 1).

The key skin sensitisation study on DTPMP acid is included in support of read-across of the reproductive toxicity study on DTPMP (5-7Na) only.

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:

28.11.1983 to 23.01.1984

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Principles of method if other than guideline:

Method: Variation of Magnusson and Kligman method.

GLP compliance:

no

Remarks:

pre-GLP

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

An LLNA study was not performed because there is an existing reliable study for skin sensitisation using the Guinea Pig Maximisation test method.

Species:

guinea pig

Strain:

Pirbright-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS

- Source: Winkelmann, Borchen

- Weight at study initiation: Average 430 grams for dosed animals, 423 grams for control animals

- Housing: Type 4 Makrolon cages

- Diet: Specialfeed Altromin 3022, ad libitum

- Water: tap water, ad libitum



ENVIRONMENTAL CONDITIONS

- Temperature (°C): ca. 23°C

- Humidity (%): 50-65%

- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light

Route:

intradermal

Vehicle:

water

Concentration / amount:

5%

Route:

other: epicutaneous (need translation)

Vehicle:

water

Concentration / amount:

5%

No. of animals per dose:

20

Details on study design:

The skin under the shoulder blade was shaved. Only animals with healthy skin were employed. 3 injections were prepared as follows:

A.     TEST ANIMALS
1 - Freund's adjuvant, volume: 0.1 mL
2 – 5% test material, volume: 0.1 mL as an aquatic solution
3 – Mixture of Freund’s adjuvant and test material as a 1:1 ratio, final concentration 5%, volume 0.1 mL

B.     CONTROL ANIMALS
1 – Freund’s adjuvant, volume 0.1 mL
2 – Aqueous solution, volume 0.1 mL
3 – Mixture of adjuvant/aqueous solution 1:1, volume 0.1 mL

A week after the initial administration, the test material was re-administered epicutaneously further down the torso.

Further sensitization was induced with a patch test. The test material was administered 5% in Vaseline. After 48 hours, the dressings were removed. The control animals were treated with Vaseline only.

14 Days after the induction treatment, a 5x5cm area was shaved in both flanks of each animal. 0.1 mL of 5% test substance in aqueous solution was applied onto the right flank and 0.1 mL of aqueous solution alone to the left flank under a patch for 24 hours.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

5% test substance in aqueous solution

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

5% test substance in aqueous solution

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

aqueous solution

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

aqueous solution

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Group:

positive control

Dose level:

N/a

No. with + reactions:

0

Total no. in group:

0

Remarks on result:

other: positive control was not specified.

Reading:

2nd reading

Group:

positive control

Dose level:

N/a

No. with + reactions:

0

Total no. in group:

0

Remarks on result:

other: positive control was not specified

Test substance group response:

Following the intracutaneous application, one animal died immediately with bleeding from the nose. No evidence of sensitisation was observed.  Necropsy findings included catarrhal enteritis, bulging stomach and cecum (indigestion), pulmonary congestion, enlarged left side of the heart and clear structure of the liver lobules.

CONTROL GROUP RESPONSES

One animal died during the exposure.

No evidence of sensitisation was observed. After removal of the patch, one animal had white dots in the left eye.

During the treatment free period, the Freund’s adjuvant resulted in necrosis and later scar tissue. After the Patch-test of 48 hours, general redness was observed and the injection sites were blood stained. Crust formation was present at injection sites in both the test and control animals.

Further details are available in the study report, however, needs proper translation.

Interpretation of results:

GHS criteria not met

Conclusions:

In a skin sensitisation study (Reliability 1), conducted according to a protocol similar to OECD Test Guideline 406 and pre-GLP, ATMP-H (without information on active acid content) was not sensitising to the skin of guinea pigs. One animal from the control group and the test group respectively died. The Freund’s adjuvant resulted in necrosis and later scar tissue. No sensitising potential was observed in the guinea pigs.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In the key skin sensitisation study, conducted according to a protocol similar to OECD Test Guideline 406 but not in compliance with GLP, ATMP-H (CAS 6419-19-8; EC 229-146-5; without information on active acid content) was not sensitising to the skin of guinea pigs (Henkel, 1984, Reliability 1).

At intradermal induction phase, 3 injections to the skin occurred for of 20 female guinea pigs and another 20 guinea pigs which served as a control group. For the test group, the first injection contained 0.1 mL of Freund’s adjuvant, the second injection contained 0.1 mL of the test material (as an aqueous solution) and the third injection contained 0.1 mL of a mixture of Freund’s adjuvant and test material as a 1:1 ratio with a final concentration of 5%. The control animals also received 3 injections, the first injection contained 0.1 mL of Freund’s adjuvant, the second injection contained 0.1 mL of an aqueous solution and the third injection contained 0.1 mL of a mixture of Freund’s adjuvant and the aqueous solution in a 1:1 ratio.

A week after the initial administration and during the epicutaneous induction phase the test material was applied epicutaneously further down the torso at 5% concentration in Vaseline. After 48 hours, the dressings were removed. The control animals were treated with Vaseline only.

14 Days after the induction treatment, challenge was performed on a on the shaved flanks of each animal. Application of 0.1 mL of the 5% test substance in aqueous solution occurred to the right flank and 0.1 mL of the aqueous solution only was applied to the left flank under a patch for 24 hours.

During the treatment free period, the Freund’s adjuvant resulted in necrosis and later scar tissue. After the epicutaneous induction, general redness was observed and the injection sites were blood stained. Crust formation was present at injection sites in both the test and control animals. Moreover, one animal in the control group died. No evidence of sensitisation was observed after challenge. After removal of the patch, one animal had white dots in the left eye.

In a supporting skin sensitisation study for the Category member ATMP-xNH4 (CAS 20592-85-2, EC 243-900-0) conducted according to OECD Test Guideline 406 and in compliance with GLP, ATMP-xNH4 was not sensitising to the skin of guinea pigs (SafePharm Laboratories, 1995, Reliability 1).

At induction, shortly before treatment on Day 0 the hair was removed from an area on the shoulder region of each animal. A row of three injections (0.1 ml) each was made on each side of the mid-line. The injections were: a) FCA plus distilled water (1:1); b) a 10% w/v formulation of the test substance in distilled water; c) a 10% w/v formulation of the test substance in a 1:1 preparation of FCA plus distilled water. Approximately 24 and 48 hours after the intradermal injection, the degree of erythema at the injection sites was evaluated. One week later (Day 7), the same area on the shoulder region was clipped again and treated with a topical application of the undiluted test substance under an occlusive dressing for 48 hours. The degree of erythema and oedema was quantified at one and 24 hours following removal of the patches.

Induction of the control animals used an identical procedure as the test animals, except the injections were: a) FCA plus distilled water in the ratio 1:1; b) distilled water; c) 50% w/v formulation of distilled water in a 1:1 mixture of FCA/distilled water. The topical applications followed the same procedure as for the test animals, but nothing was applied to the patch. Skin reactions were quantified.

At challenge, shortly before treatment on Day 21, an area of skin on both flanks of each animal was clipped free of hair. A square filter paper patch saturated with the undiluted test substance was applied to the shorn right flank of each animal and was held in place with a strip of surgical adhesive tape. To ensure that the maximum non-irritant concentration was used at challenge, the test substance at a concentration of 75% v/v in distilled water was similarly applied to a skin site on the left shorn flank. The patches were covered with an occlusive dressing. After 24 hours the dressing was removed. The challenge sites were swabbed with cotton wool soaked in distilled water to remove residual material. Prior to the observation period, the flanks were clipped to remove regrown hair.

Approximately 24 and 48 hours after challenge dressing removal, the degree of erythema and oedema was quantified, and any other reactions recorded. The percentage of test animals that showed a more severe reaction at the test substance challenge site than the most severe reaction observed in the control animals, was compared using the scale: 0% = non-sensitiser; >0-8% = weak sensitiser; >8-28 = mild sensitiser; >28-64% = moderate sensitiser; >64-80% = strong sensitiser; >80-100% = extreme sensitiser.

Neither of the test group animals demonstrated skin reactions indicative of skin sensitisation.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

There are no data for respiratory sensitisation.

Justification for classification or non-classification

Based on the available data, no classification is required for skin sensitisation for ATMP-H according to Regulation (EC) No 1272/2008.