O,O,O-triphenyl phosphorothioate

Endpoint summary

Description of key information

GPMT (guinea pig, male): negative (test material with low purity)

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:

1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Version / remarks:

92/69/EWG, B.6 (Guinea Pig maximization test (GPMT))

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Valid in vivo data from a guinea pig study is available.

Species:

guinea pig

Sex:

male

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: D. Hall, Newchurch, Staffordshire, England.
- Age at study initiation: Approximately four to five weeks of age.
- Weight at study initiation: 292 to 339 g.
- Housing: in groups of five in suspended metal cages with wire mesh floors
- Diet: ad libitum (A vitamin C enriched guinea-pig diet FD2; hay was given weekly) diet was not analysed for nutrients, possible contaminants or microorganisms.
- Water: ad libitum (analysed weekly for contamination).
- Acclimation period: For five days prior to allocation to the main study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.
- Humidity (%): 30 - 70.
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

An additional six animals, from the same supplier, were used for the preliminary investigations.

Route:

intradermal and epicutaneous

Vehicle:

coconut oil

Concentration / amount:

1 % v/v in Alembicol D (A product of coconut oil, supplied by Alembic Products, Saltney, Chester, England).

Route:

epicutaneous, occlusive

Vehicle:

coconut oil

Concentration / amount:

100 %

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

coconut oil

Concentration / amount:

100 % and 50 % v/v in Alembicol D.

No. of animals per dose:

Number of animals in test group: 10
Number of animals in negative control group: 5

Details on study design:

RANGE FINDING TESTS:
Animals for these investigations were pre-treated with an intradermal injection of Freund's complete adjuvant, 50:50 with water for irrigation (Ph. Eur), approximately two weeks prior to the start of the preliminary investigations.

MAIN STUDY
A. INDUCTION EXPOSURE
Intradermal Injection
- Site/Area: Back (scapular region)/2 x 4 cm
- No. of injections/animal: 6 injections in pairs each.
- Test substance group (cranial; 2 injections side by side): Freund's complete adjuvant (FCA) blended (1:1, v/v) with water (Ph.Eur.).
- Test substance group (middle; 2 injections side by side): The test article (1%) in vehicle.
- Test substance group (caudal; 2 injections side by side): 50% Freund's complete adjuvant blended (1:1, v/v) with water + 1 % test article in vehicle.
- Control group (cranial; 2 injections side by side): Freund's complete adjuvant (FCA) blended (1:1, v/v) with water (Ph.Eur.).
- Control group (middle; 2 injections side by side): Vehicle.
- Control group (caudal; 2 injections side by side): 50% Freund's complete adjuvant blended (1:1, v/v) with water + vehicle
- Volume per injection: 0.1 ml
- Evaluation (hr after injection): from 24 hour till day 7
- Exposure period: Single exposure

Epicutaneous induction exposure
- Time schedule: 7 days after intradermal injection
- Site: same as intradermal injections (site was pretreated 24 hours before with 0.5 ml per site of 10% w/w sodium lauryl sulphate in petrolatum)
- Frequency of applications: Once.
- Area of application: 2 x 4 cm (on Whatman No. 3)
- Concentrations: undiluted test article (test group) and water (control group)
- Volume applied: 0.4ml/animal
- Type of coverage: occlusive (impemeable plastic adhesive tape (50 ram width "Blenderm") + adhesive bandage (50 mm width "Elastoplast")
- Duration: 48 hours
- Evaluation (hr after challenge): directly after removal of patch

B. CHALLENGE EXPOSURE (all animals)
- Frequency of exposure: once
- Time schedule: 2 weeks after termination of induction exposures
- Site: left flank
- Area of application: 2 x 2 cm (Whatman No. 3 paper)
- Concentrations: undiluted (anterior flank) and 50% (v/v) in vehicle
- Volume applied: 0.2 ml/animal
- Type of coverage: occlusive (impemeable plastic adhesive tape (50 ram width "Blenderm") + adhesive bandage (50 mm width "Elastoplast")
- Duration: 24 hours
- Evaluation (hr after challenge): 24 and 48 hours after termination of exposure

SCORING SYSTEM: OECD Draize system
Erythema and eschar formation:
No erythema 0
Slight erythema 1
Well-defined erythema 2
Moderate erythema 3
Severe erythema (beet redness) to slight eschar formation (injuries in depth) 4

Oedema formation:
No oedema 0
Slight oedema 1
Well-defined (edges of area well defined by definite raising) 2
Moderate oedema (raised approximately 1 millimetre) 3
Severe oedema (raised more than 1 millimetre and extending beyond the area of exposure) 4

OTHER
All animals were observed daily for signs of ill health or toxicity. The body weight of each guinea-pig on the main study was recorded on Day 1 (day of intradermal injections) and on the last day observations were made of dermal responses to the challenge applications.

Positive control substance(s):

yes

Remarks:

The sensitivity of the guinea-pig strain used is checked periodically at HRC with hexyl cinnamic aldehyde, a known sensitiser

Positive control results:

See Table 1 for summary of positive control data

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

100 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

Refer to Table 2

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

50 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

Refer to Table 2

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

100 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

Refer to Table 2

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

50 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

Refer to Table 2

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

100 %

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

Refer to Table 2

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

50 %

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

Refer to Table 2

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

100 %

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

Refer to Table 2

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

50 %

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

Refer to Table 2

Table 1. Summary of positive control data using hexyl cinnamic aldehyde

M&K R&D No.	Number of animals		Dates of study		Dates of receipt of HCA	Dose levels % (aqueous dilutions)			Results
						Induction		Challenge
	Test	Control	Start	Finish		Intradermal	Topical		Positive	Inconclusive	Negative
1	10	5	08.12.92	09.01.93	29.10.92	10	As Supplied	As supplied and 50	10/10	0/10	0/10
IE	10	10	20.07.93	16.08.93	11.06.93	10	As Supplied	As supplied and 50	9/10	0/10	1/10
2A	10	10	15.03.94	11.04.94	11.06.93	10	As Supplied	As supplied and 50	10/10	0/10	0/10
2D	10	10	06.09.94	01.10.94	12.08.94	10	As Supplied	As supplied and 50	9/10	0/10	1/10
2G*	10	10	28.09.94	23.10.94	12.08.94	10	As Supplied	As supplied and 50	10/10	0/10	0/10
2H	10	10	05.10.94	30.10.94	12.08.94	10	As Supplied	As supplied and 50	10/10	0/10	0/10
3A	10	10	24.01.95	18.02.95	24.10.94	10	As Supplied	As supplied and 50	8/10	1/10	1/10

Animals supplied by D. Hall Newchurch.

* Animals supplied by Interfauna (UK) Ltd.

Hexyl cinnamic aldehyde obtained from Aldrich Chemicals Co.

Table 2. Dermal reactions observed after each induction

Site	Intradermal injection		Topical application
	Test animals	Control animals	Test animals	Control animals
1	Necrosis	Necrosis	Slight erythema	Slight erythema
2	Slight irritation	Slight irritation
3	Necrosis	Necrosis

 

Interpretation of results:

GHS criteria not met

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In a dermal sensitisation study performed according to the EU Method B.6 (Skin Sensitisation) 92/69/EWG, 4-5 weeks old guinea pigs were used to test for contact sensitization of the test article (with low purity). The control group consisted of 5 animals and the test group was composed of 10 animals. Intradermal inductions were performed with 1% of the test article in Alembicol D mixed with Freund's complete adjuvant (FCA). 7 days later, topical inductions were carried out under occlusive conditions for 48 hours with the undiluted test article. Following a 2 week treatment free interval, challenge exposures were performed epicutaneously (occlusive, 24 hours) with the undiluted test article in Alembicol D. Evaluation of the skin reactions was performed 24 and 48 hours after challenge exposures. No animal showed a positive reaction in the treatment as well as the control group. Assays with the positive control substance (hexyl cinnamic aldehyde (CAS No. 101-86-0)) performed regularly in the same laboratory caused the expected reaction (1995).

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for the purpose of classification under Regulation 1272/2008. Based on the criteria laid down in Regulation (EC) No. 1272/2008, classification as a skin sensitizer is not warranted.