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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1992-09-16 to 1992-10-31
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Guideline study (The study was conducted according to the OECD 406 "Skin sensitisation", adopted 12 May 1981. When the study was conducted the OECD 406 of 10.07.1992 was already effective, so the study was compared to that guideline.) Minor deviations with no effect on the study results or on the high reliability of the study: - 0.2 mL of 10 % w/w sodium lauryl sulphate in Vaseline was used in order to create local irritation after intradermal injections instead of 0.5 mL. - another grading scale than the one stated in the guideline was used.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report date:
1996

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
adopted 12 May 1981
Deviations:
yes
Remarks:
Minor deviations see "rationale for reliability"
GLP compliance:
yes
Remarks:
The study report states that the study was conducted in compliance with Good Laboratory Practice Standards, e.g. by the United Kingdom Compliance Programme, Department of Health & Social Security 1986 and subsequent revision, Department of Health, 1989.
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The conduct of this study was prior to the establishment of the LLNA method (OECD 429).

Test material

Constituent 1
Reference substance name:
Diammonium dimolybdate
EC Number:
248-517-2
EC Name:
Diammonium dimolybdate
Cas Number:
27546-07-2
IUPAC Name:
Diammonium dimolybdate
Details on test material:
- Name of test material (as cited in study report): Ammonium dimolybdate
- Physical state: white powder
- Analytical purity: > 99.9 %, calculated from reported Mo content (56,4 %)
- Composition of test material, percentage of components: Mo =56.4; NH4 = 10.5%
- Storage condition of test material: room temperature

No further significant information no test material was stated.

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: approximately six to seven weeks
- Weight at study initiation: weight range of 280 to 332 g on arrival
- Housing: The guinea pigs were housed in groups of ten in suspended metal cages with wire mesh floors.
- Diet: A vitamin C enriched guinea-pig diet FD1 (ad libitum); Hay was given weekly.
- Water (ad libitum): drinking water
- Acclimation period: nineteen days prior to allocation to the main study


ENVIRONMENTAL CONDITIONS
- Temperature: approximately 21 °C
- Relative humidity: 30 - 70 %
- Air exchanges: approximately 15 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 h/ 12h

No further significant information on test animals was stated.

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
water
Concentration / amount:
The following concentrations are based on a range finding test.
Induction intradermal injections - test animals (main study)
1. Freund's complete adjuvant was diluted with an equal volume of water for irrigation (Ph.Eur.)
2. Ammonium dimolybdate, 0.1 % w/w in water for irrigation
3. Ammonium dimolybdate, 0.1 % w/w in a 50:50 mixture of Freund's complete adjuvant and water for irrigation
Induction topical application - test animals (main study)
Ammonium dimolybdate, 90% w/w in distilled water

First Challenge - control and test animals (main study)
Ammonium dimolybdate, 90 and 45% w/w in distilled water

Second challenge (not based on the rang finding test; see details on study design)
Ammonium dimolybdate, 50 and 25 % w/w in distilled water

Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
The following concentrations are based on a range finding test.
Induction intradermal injections - test animals (main study)
1. Freund's complete adjuvant was diluted with an equal volume of water for irrigation (Ph.Eur.)
2. Ammonium dimolybdate, 0.1 % w/w in water for irrigation
3. Ammonium dimolybdate, 0.1 % w/w in a 50:50 mixture of Freund's complete adjuvant and water for irrigation
Induction topical application - test animals (main study)
Ammonium dimolybdate, 90% w/w in distilled water

First Challenge - control and test animals (main study)
Ammonium dimolybdate, 90 and 45% w/w in distilled water

Second challenge (not based on the rang finding test; see details on study design)
Ammonium dimolybdate, 50 and 25 % w/w in distilled water

No. of animals per dose:
Preliminary study: six animals
Main study: 20 test animals
Details on study design:
MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (intradermal injections & topical application)
- Exposure period: topical application: 48 hours
- Test groups: Intradermal injections: Freund's complete adjuvant was diluted with an equal volume of water for irrigation (Ph.Eur.); Ammonium dimolybdate in water for irrigation; Ammonium dimolybdate in a 50:50 mixture of Freund's complete adjuvant and water for irrigation. A volume of 0.1 ml was injected.
Topical application: Approximately 0.4 ml of Ammonium dimolybdate in distilled water
- Control group: During the induction phase, the control animals were treated similarly to the test animals with the exception that the test substance was omitted from the intradermal injections and topical application.
- Site: A 40 x 60 mm area of dorsal skin on the scapular region of the guinea-pig was clipped free of hair with electric clippers. Three pairs of intradermal injections were made into a 2 x 4 cm area within the clipped area. The same 40 x 60 mm intrascapular area was clipped and shaved for the topical application.
- Frequency of applications: The intradermal injections were given once and 7 days later the topical application was carried out.


B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: Day 21
- Exposure period: 24 hours
- Site (control and test group): Hair was removed by clipping and then shaving from an area on the left flank. A 20 x 20 mm patch of Whatman No. 3 paper was saturated with approximately 0.2 ml of Ammonium dimolybdate, 90 % w/w in distilled water and applied to an anterior site on the flank. Ammonium dimolybdate, 45 % w/w in distilled water was applied in a similar manner to a posterior site.
- Evaluation (hr after challenge): The challenge sites were evaluated 24, 48 and 72 hours after removal of the patches.

OTHER:
A second challenge application was made one week later to differentiate between irritation and allergic resonses following observation of irritant reactions in the control animals after the first challenge. The method employed was similar to that described earlier, with the exception that on this occasion Ammonium dimolybdate, 50 and 25% w/w in distilled water, was applied to the right flank of all the control and test animals.

GRADING SYSTEM for evaluating dermal reactions:

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 oedema (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

Any other lesion not covered by this scoring system was described.

No further significant information on study design were stated.
Challenge controls:
20 control animals. The control animals were challend topically two weeks after the topical induction application using Ammonium dimolybdate, 90 and 45 % w/w in distilled water.
Positive control substance(s):
yes
Remarks:
formalin

Results and discussion

Positive control results:
10 females were tested with formalin and 10 females served as a control. All females treated with formalin showed a positive response.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
Ammonium dimolybdate, 45% w/w in distilled water
No. with + reactions:
1
Total no. in group:
20
Clinical observations:
Slight erythema in one animal
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: Ammonium dimolybdate, 45% w/w in distilled water. No with. + reactions: 1.0. Total no. in groups: 20.0. Clinical observations: Slight erythema in one animal.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
Ammonium dimolybdate, 45 % w/w in distilled water
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: Ammonium dimolybdate, 45 % w/w in distilled water. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
negative control
Dose level:
Ammonium dimolybdate, 45% w/w in distilled water
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: other: 3rd reading. . Hours after challenge: 72.0. Group: negative control. Dose level: Ammonium dimolybdate, 45% w/w in distilled water. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
Ammonium dimolybdate, 45 % w/w in distilled water
No. with + reactions:
4
Total no. in group:
20
Clinical observations:
well-defined erythema in two animals; slight erythema in one animal: slight erythema and slight oedema in one animal
Remarks on result:
other: see Remark
Remarks:
Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: Ammonium dimolybdate, 45 % w/w in distilled water. No with. + reactions: 4.0. Total no. in groups: 20.0. Clinical observations: well-defined erythema in two animals; slight erythema in one animal: slight erythema and slight oedema in one animal.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
Ammonium dimolybdate, 45 % w/w in distilled water
No. with + reactions:
4
Total no. in group:
20
Clinical observations:
Well-defined erythema in two animals; well-defined erythema and slight oedema in one animal; slight erythema in one animal
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: Ammonium dimolybdate, 45 % w/w in distilled water. No with. + reactions: 4.0. Total no. in groups: 20.0. Clinical observations: Well-defined erythema in two animals; well-defined erythema and slight oedema in one animal; slight erythema in one animal .
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
test chemical
Dose level:
Ammonium dimolybdate, 45 % w/w in distilled water
No. with + reactions:
4
Total no. in group:
20
Clinical observations:
Well-defined erythema two animals; well-defined erythema and slight oedema in one animal; slight erythema in one animal
Remarks on result:
other: see Remark
Remarks:
Reading: other: 3rd reading. . Hours after challenge: 72.0. Group: test group. Dose level: Ammonium dimolybdate, 45 % w/w in distilled water. No with. + reactions: 4.0. Total no. in groups: 20.0. Clinical observations: Well-defined erythema two animals; well-defined erythema and slight oedema in one animal; slight erythema in one animal.
Reading:
rechallenge
Hours after challenge:
24
Group:
negative control
Dose level:
Ammonium dimolybdate, 25 and 50 % w/w in distilled water
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 24.0. Group: negative control. Dose level: Ammonium dimolybdate, 25 and 50 % w/w in distilled water. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
rechallenge
Hours after challenge:
48
Group:
negative control
Dose level:
Ammonium dimolybdate, 25 and 50 % w/w in distilled water
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 48.0. Group: negative control. Dose level: Ammonium dimolybdate, 25 and 50 % w/w in distilled water. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
rechallenge
Hours after challenge:
72
Group:
negative control
Dose level:
Ammonium dimolybdate, 25 and 50 % w/w in distilled water
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 72.0. Group: negative control. Dose level: Ammonium dimolybdate, 25 and 50 % w/w in distilled water. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
rechallenge
Hours after challenge:
24
Group:
test chemical
Dose level:
Ammonium dimolybdate, 50 % w/w in distilled water
No. with + reactions:
3
Total no. in group:
20
Clinical observations:
Slight erythema in two animals; well-defined erythema in one animal
Remarks on result:
other: see Remark
Remarks:
Reading: rechallenge. . Hours after challenge: 24.0. Group: test group. Dose level: Ammonium dimolybdate, 50 % w/w in distilled water. No with. + reactions: 3.0. Total no. in groups: 20.0. Clinical observations: Slight erythema in two animals; well-defined erythema in one animal.
Reading:
rechallenge
Hours after challenge:
48
Group:
test chemical
Dose level:
Ammonium dimolybdate, 50 % w/w in distilled water
No. with + reactions:
1
Total no. in group:
20
Clinical observations:
Sligth erythema in one animal
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 48.0. Group: test group. Dose level: Ammonium dimolybdate, 50 % w/w in distilled water. No with. + reactions: 1.0. Total no. in groups: 20.0. Clinical observations: Sligth erythema in one animal.
Reading:
rechallenge
Hours after challenge:
72
Group:
test chemical
Dose level:
Ammonium dimolybdate, 50 % w/w in distilled water
No. with + reactions:
1
Total no. in group:
20
Clinical observations:
Slight erythema in one animal
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 72.0. Group: test group. Dose level: Ammonium dimolybdate, 50 % w/w in distilled water. No with. + reactions: 1.0. Total no. in groups: 20.0. Clinical observations: Slight erythema in one animal.
Reading:
rechallenge
Hours after challenge:
24
Group:
test chemical
Dose level:
Ammonium dimolybdate, 25 % in distilled water
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 24.0. Group: test group. Dose level: Ammonium dimolybdate, 25 % in distilled water. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
rechallenge
Hours after challenge:
48
Group:
test chemical
Dose level:
Ammonium dimolybdate, 25 % in distilled water
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 48.0. Group: test group. Dose level: Ammonium dimolybdate, 25 % in distilled water. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
rechallenge
Hours after challenge:
72
Group:
test chemical
Dose level:
Ammonium dimolybdate, 25 % in distilled water
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 72.0. Group: test group. Dose level: Ammonium dimolybdate, 25 % in distilled water. No with. + reactions: 0.0. Total no. in groups: 20.0.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
In this test, performed in twenty albino guinea-pigs Ammonium dimolybdate produced evidence of skin sensitisation (delayed contact hypersensitivity) in four animals. This was confirmed by a second challenge application for one animal only.