Benzoic acid, 4-(acetylamino)-5-iodo-2-methoxy-, methyl ester

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Protocol approval date: 18 June 2001 - Report approval date: 18 October 2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study report did contain a reference to an international guideline with sufficient details but not totally GLP compliant. The study was performed according to SOP in a laboratory that conforms to GLP, but the report was not audited by the QAU.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

Buehler test

Principles of method if other than guideline:

Also in accordance with the Guidelines published in the European Community Gazette (L383A, 29 December 1992).

GLP compliance:

no

Remarks:

Study performed according to SOP in a laboratory that conforms to GLP, but report not audited by the QAU

Type of study:

Buehler test

Justification for non-LLNA method:

Study was performed 2001, which is before the OECD guideline for the LLNA method was adopted (2002).

Test material

Test material information

Constituent 1

Reference substance name:

Iodomesac

IUPAC Name:

Iodomesac

Constituent 2

Reference substance name:

Methyl 4-(acetylamino)-5-iodo-2-methoxybenzoate

IUPAC Name:

Methyl 4-(acetylamino)-5-iodo-2-methoxybenzoate

Constituent 3

Reference substance name:

methyl 4-acetamido-5-iodo-2-methoxybenzoate

EC Number:

606-440-5

Cas Number:

201214-53-1

Molecular formula:

C11H12INO4

IUPAC Name:

methyl 4-acetamido-5-iodo-2-methoxybenzoate

Details on test material:

- Test compound (batch No.) Iodomesac (1S00004)
- Route of administration Cutaneous (occlusive bandage)
- Formulation Powder form suspended in petrolatum just before treatment
- Expiration date of the lot/batch: 15/05/2001
- A certificate of analysis is included in the report.

In vivo test system

Test animals

Species:

guinea pig

Strain:

Hartley

Sex:

male

Details on test animals and environmental conditions:

Supplier: Charles River France, Saint-Aubin lès Elbeuf, 76410 Cléon, France
Age and body weight at initiation of treatment: Approximately 8 weeks and 530 g ± 100 g
Environment and husbandry:
- Housed in wire mesh bottomed, stainless steel cages; space allocated at initiation of treatment: 2898 cm² x 20 cm (4 animals/cage maximum).
- Temperature: 22 ± 2 ° C
- Relative humidity: 40-70%
- Air flow: 10-12 changes/hour without recirculation
- Light cycle: 12/24 hours
Diet and water:
- Diet: complete commercial rodent diet (re. 114C - 4.5 mm - U.A.R.) ad libitum.
- Water supply: free access to tap water through automatic waterers.
Pre-treatment procedures:
- Stabilisation: at least 2 weeks before beginning treatment.
- Number of animals: 50 males.
- Number of animals/group: 20 males (main study) or 5 males (preliminary assay).
- Allocation to experimental groups : at random.
- Identification: ear tattoo with the identity number (main study) or mark with felt-tip pen (preliminary assay).

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

epicutaneous, occlusive

Vehicle:

petrolatum

Induction 2

Concentration / amount:

See below.

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

petrolatum

Challenge 2

Concentration / amount:

See below.

No. of animals per dose:

Preliminary assay: 5 males
Final assay: 20 males

Preliminary assay:
Concentration of Iodomesac in Petrolatum:
Occlusive bandage (6 h) (0.2 mL)
No. of animals Right flank Left flank
5 10% 5%
5 30% 20%

Final assay:
Control group (10): Induction phase: Petrolatum; Challenge 10% Iodomesac in petrolatum on the right flank
Treated group Induction phase (10): 30% Iodomesac in petrolatum; Challenge 10% Iodomesac in petrolatum on the right flank
The left flank was not treated.

Details on study design:

PRELIMINARY ASSAY:
determination of MNIC (Maximum Non-Irritant Concentration) and MIC (Minimal Irritant Concentration)
Dosing frequency: once. All dosages and concentrations are expressed in terms of the material received.
Animals concerned: .
- 2 groups of 5 additional guinea-pigs
- the hind flanks of each animal are sheared.
Method:
- Treatment: application under occlusion for 6 hours of an approximately 5 cm² patch (type filter paper Whatman GF/C) soaked with 0.2 ml test substance diluted at various concentrations in its vehicle.
- Frequency of observations: local reactions are recorded 24 and 48 hours after removing the occlusive bandage.
- Concentration retained: minimal concentration, which induces a reaction (MIC - Induction phase) and maximum concentration, which does not induce any reaction (MNIC - challenge phase).

FINAL ASSAY:
1. First period: sensitization induction phase
Animals concerned:
- all animals
- the right flank anterior part of each animal is sheared.
Method:
- Treated group: Days 1, 8 and 15, application under occlusion for 6 hours of an approximately 5 cm² patch (type filter paper Whatman GF/C) soaked with 0.2 ml test substance at a 30% (MIC) concentration in its vehicle. The left flank is not treated.
- Control group: the control group receives the vehicle according to the same procedure.
Animals recovery for 2 weeks approximately.
2. Second period: challenge phase
Animals concerned:
- all animals
- the posterior right and left dorsal areas of each animal are sheared.
Method:
- Day 28:
application under occlusion for 6 hours on the right flank of an approxiately 5 cm² patch (type filter paper Whatman GF/C) soaked with 0.2 ml test
substance at a 10% (MNIC) concentration in its vehicle. The left flank is not treated.
- Frequency of observations: local reactions are recorded 24 and 48 hours after removing the occlusive bandage.

ASSESSMENT OF CUTANEOUS SENSITIZATION
Method:
- Assessment according to Buelher’s technique.
- Results are noted for each animal on the basis of skin reactions, in order to determine the reactivity specific to the allergen.
Erythema
0 No reaction
1 Slight scattered redness
2 Moderate diffuse redness
3 Marked swollen redness
Edema
0 No edema
1 Very slight edema (barely perceptible)
2 Slight edema (edges of area well-defined by definite raising)
3 Moderate edema (raised approximately 1 mm)
4 Severe edema (raised more than 1 mm and extending beyond the area
of exposure)
Determination of the allergenicity degree: on the basis of the number of animals presenting a reaction.
Five degrees are defined according to the following scale:

Percentage of animals presenting a reaction / Allergenicity degree
0 - 8 I
9 - 28 II
29 - 64 III
65 - 80 IV
81 - 100 V


CLINICAL EXAMINATIONS
Clinical signs and mortality:
- Frequency: once daily, 5 days/7, throughout the study.
- Animals concerned: all animals.
- Clinical signs: date of onset and progression are recorded. Visual observation.
- Mortality: post-mortem examination of decedents or of animals killed in extremis.
Body weight:
- Frequency: prior to treatment, then weekly.
- Animals concerned: all animals.
- Parameter: body weight (g).
Necropsy:
In case of positive reaction requiring deeper interpretation:
- PathData number: 30078.
- Necropsy day: on day 30.
Animals concerned: all animals, sacrificed by exsanguination while under general anesthesia with pentobarbital sodium, 1 ml/kg, I.P.
Macroscopy:
- cavities, organs and/or tissues to be examined: Right and Left skin and subcutaneous tissues
- organs and tissues taken: Right and Left skin and subcutaneous tissues
Light microscopy:
- organs and tissues examined: Right and Left skin and subcutaneous tissues
When the interpretation of the results does not require necropsy, the animals are euthanazied with no organ sampling.
In case of mortality during the study, samples are taken to justify the cause of death.
Findings are noted in the necropsy book.
The following samples are taken:
- macroscopic changes
- liver
- kidneys
- heart
- lungs

Challenge controls:

Yes, see above.

Positive control substance(s):

not required

Results and discussion

In vivo (non-LLNA)

Results

Results 1

Reading:

other: Irritancy

Hours after challenge:

6

Group:

test chemical

Dose level:

right: 10 & 30 %; left: 5 & 20 %.

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

There was no irritant concentration. Based on that result and after solubility assay, the following standard concentrations were retained: 10% for MNIC and 30% for MIC.

Remarks on result:

other: see Remark

Remarks:

Reading: other: Irritancy. . Hours after challenge: 6.0. Group: test group. Dose level: right: 10 & 30 %; left: 5 & 20 %.. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: There was no irritant concentration. Based on that result and after solubility assay, the following standard concentrations were retained: 10% for MNIC and 30% for MIC..

Results 2

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

30 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

No treatment-related changes.

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 30 %. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No treatment-related changes. .

Results 3

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

30 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

No treatment-related changes.

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 30 %. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No treatment-related changes. .

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Iodomesac had no cutaneous sensitizing effect in the guinea pig: no reaction was observed in either the sensitized group or the nonsensitized group and no treatment-related changes were observed for clinical signs and body weight (weekly).