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Description of key information

The skin sensitization potential of3,5 Diaminobenzoic acid (535-87-5)was estimated by using OECD QSAR toolbox v3.4 with log kow as the primary descriptor and considering the six closest read across substances.3,5 Diaminobenzoic acid (535-87-5)was predicted to be non sensitizing to the skin of female CBA/CaOlaHsd mice.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification
Justification for type of information:
Data is from OECD QSAR toolbox v3.4 and the QMRF report has been attached
Reference:
Composition 1
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Principles of method if other than guideline:
Prediction was done using OECD QSAR toolbox v3.4
GLP compliance:
not specified
Type of study:
mouse local lymphnode assay (LLNA)
Test material information:
Composition 1
Specific details on test material used for the study:
- Name of test material (as cited in study report): 3,5-Diaminobenzoic acid
- Molecular formula: C7H8N2O2
- Molecular weight: 152.1522 g/mol
- Substance type: Organic
- Physical state: Solid
Species:
mouse
Strain:
other: CBA/CaOlaHsd
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Netherlands
- Age at study initiation: 7 - 8 weeks
- Weight at study initiation: 18.4 - 22.2 gr
- Housing: single, macrolone cage
- Diet: pelleted standard diet (Harlan Winkelmann GmbH) ad libitum
- Water: tap water ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22+-3
- Humidity (%): 30 - 72
- Photoperiod: 12 hrs dark /12 hrs light):
Vehicle:
dimethyl sulphoxide
Concentration:

0, 1.5, 3, 6 %
No. of animals per dose:
5
Details on study design:
Administration and exposure: In RCC-CCR Study 1104502 (non-GLP) 6% of the test item was demonstrated to be the highest concentration not inducing systemic toxicity. In this study at a concentration of 12.5 % two of four animals died after treatment with the test item. The top dose of the test item (6%) is the highest technically achievable concentration whilst avoiding systemic toxicity and excessive local irritation.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
EC3 = (a-c) [(3-d)/(b-d)] + c
Parameter:
SI
Test group / Remarks:
No mortality or sensitization effect was observed.
Remarks on result:
other: Not sensitizing

The prediction was based on dataset comprised from the following descriptors: "Skin Sensitisation"
Estimation method: Takes mode value from the 5 nearest neighbours
Domain  logical expression:Result: In Domain

((((((((((("a" or "b" or "c" or "d" or "e" )  and "f" )  and "g" )  and "h" )  and ("i" and ( not "j") )  )  and ("k" and ( not "l") )  )  and ("m" and ( not "n") )  )  and ("o" and ( not "p") )  )  and ("q" and ( not "r") )  )  and ("s" and ( not "t") )  )  and ("u" and "v" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Anilines (Acute toxicity) by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Aminoaniline, meta AND Aniline AND Aryl AND Carboxylic acid by Organic Functional groups

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Aminoaniline, meta AND Carboxylic acid AND Overlapping groups by Organic Functional groups (nested)

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Acid, aromatic attach [-COOH] AND Alcohol, olefinic attach [-OH] AND Aliphatic Nitrogen, one aromatic attach [-N] AND Aromatic Carbon [C] AND Carbonyl, olefinic attach [-C(=O)-] AND Carbonyl, one aromatic attach [-C(=O)-] AND Miscellaneous sulfide (=S) or oxide (=O) AND Olefinic carbon [=CH- or =C<] by Organic functional groups (US EPA)

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Amine AND Aromatic compound AND Carbonic acid derivative AND Carboxylic acid AND Carboxylic acid derivative AND Primary amine AND Primary aromatic amine by Organic functional groups, Norbert Haider (checkmol)

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as No superfragment by Superfragments ONLY

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Bioavailable by Lipinski Rule Oasis ONLY

Domain logical expression index: "h"

Similarity boundary:Target: Nc1cc(N)cc(C(O)=O)c1
Threshold=50%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Non-Metals by Groups of elements

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Alkali Earth OR Halogens by Groups of elements

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as No alert found by Respiratory sensitisation

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Pro-Michael Addition OR Pro-Michael Addition >> Pro-quinone and related OR Pro-Michael Addition >> Pro-quinone and related >> Aminophenols OR Pro-Michael Addition >> Pro-quinone and related >> Phenylenediamines by Respiratory sensitisation

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as No alert found by Protein binding alerts for skin sensitization by OASIS v1.4

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Ester aminolysis OR Acylation >> Ester aminolysis >> Amides by Protein binding alerts for skin sensitization by OASIS v1.4

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as No alert found by Protein binding alerts for Chromosomal aberration by OASIS v.1.2

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >> Michael addition to the quinoid type structures OR AN2 >> Michael addition to the quinoid type structures >> Substituted Anilines by Protein binding alerts for Chromosomal aberration by OASIS v.1.2

Domain logical expression index: "q"

Referential boundary: The target chemical should be classified as Aromatic Amine Type Compounds by Oncologic Primary Classification

Domain logical expression index: "r"

Referential boundary: The target chemical should be classified as Phenol Type Compounds by Oncologic Primary Classification

Domain logical expression index: "s"

Referential boundary: The target chemical should be classified as No alert found by DNA alerts for AMES by OASIS v.1.4

Domain logical expression index: "t"

Referential boundary: The target chemical should be classified as Radical OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitroaniline Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) >> Single-Ring Substituted Primary Aromatic Amines OR SN1 OR SN1 >> Nucleophilic attack after nitrenium ion formation OR SN1 >> Nucleophilic attack after nitrenium ion formation >> Single-Ring Substituted Primary Aromatic Amines OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitroaniline Derivatives by DNA alerts for AMES by OASIS v.1.4

Domain logical expression index: "u"

Parametric boundary:The target chemical should have a value of log Kow which is >= -2.08

Domain logical expression index: "v"

Parametric boundary:The target chemical should have a value of log Kow which is <= 0.773

Interpretation of results:
other: not sensitising
Conclusions:
The skin sensitization potential of 3,5 Diaminobenzoic acid (535-87-5) was estimated by using OECD QSAR toolbox v3.4 with log kow as the primary descriptor and considering the six closest read across substances. 3,5 Diaminobenzoic acid (535-87-5)was predicted to be non sensitizing to the skin of female CBA/CaOlaHsd mice.
Executive summary:

The skin sensitization potential of 3,5 Diaminobenzoic acid (535-87-5) was estimated by  using OECD QSAR toolbox v3.4 with log kow as the primary descriptor and considering the six closest read across substances. 3,5 Diaminobenzoic acid (535-87-5)was predicted to be non sensitizing to the skin of female CBA/CaOlaHsd mice.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Skin sensitization

In different studies3,5 Diaminobenzoic acid (535-87-5)has been investigated for potential for dermal sensitization to a greater or lesser extent. The prediction and studies are based on in vivo experiments in mouse for target chemical disodium3,5 Diaminobenzoic acid (535-87-5)and its structurally similar read across substances Sulphanilic acid (121-57-3)and 4-aminobenzoic acid (205-753-0). The predicted data using the OECD QSAR toolbox has also been compared with the experimental data.

The skin sensitization potential of3,5 Diaminobenzoic acid (535-87-5)was estimated by SSS (2017) using OECD QSAR toolbox v3.4 with log kow as the primary descriptor and considering the six closest read across substances.3,5 Diaminobenzoic acid (535-87-5)was predicted to be non sensitizing to the skin of female CBA/CaOlaHsd mice.

 It is supported by experimental data conducted by D. A. Basketter et al.(Contact Dermatitis ,1992) on structurally similar read across substance Sulphanilic acid (121-57-3) onDunkin-Hartleyguinea pigs.The read across substances share high similarity in structure and log kow .Therefore, it is acceptable to derive information on skin sensitization from the analogue substance. The cumulative contact enhancement test (CCET) was carried out with the test material Sulphanilic Acid to study the sensitization potential. To induce sensitization a group of 10 guinea pig were albino Dunkin-Hartley strain and weighed approximately 350 g at the start of testing were treated twice weekly for 2 weeks using 24 hrs occluded patches containing 25% Sulphanilic acid(121-57-3)in vehicle 0.9% PEG 400 (50/50, w/w) over the shoulder region.Immediately before the third application, the test and 4 control guinea pigs were injected with Freund's complete adjuvant in the shoulder region at the site to be patched. Test and control animals were challenged after a 12 days rest period by open application at the maximum non-irritant concentration (25%). Challenge sites were scored for erythema (scale 0-3) at 24- h and 48 h. Sulphanilic Acid did not produce any positive reaction and failed to induce any evidence of sensitization at higher concentrations in the cumulative contact enhancement test (CCET). Therefore Sulphanilic Acid was considered to be non -sensitizing.

It is supported by experimental data conducted by D. A. Basketter et al.(Contact Dermatitis ,1992) on structurally similar read across substance Sulphanilic acid (121-57-3) onmouse by LLNA..The read across substances share high similarity in structure and log kow .Therefore, it is acceptable to derive information on skin sensitization from the analogue substance. Mice of CBA/Ca strain, of either sex were used. Groups of mice to (n=4) were treated daily for 3 consecutive days by topical application of 25 μl of 1 of 3 concentrations of sulphanilic acid (in the range 2.5%-25%) on the dorsum of each ear.Control mice received vehicle alone, 4/5 days after the first topical application. mice were injected via the tail vein with 250 id of phosphate buffered saline (PBS) containing 20 μCi of 'H-methyl thymidine (HTdR), specific activity 2.0 Ci/mmol (Amersham International, Amersham. UK). The proliferative response of LNC was expressed as radioactive disintegrations per Minute per lymph node (dpm/node) and as the ratio of 'HTdR incorporation by test nodes relative to control nodes (T/C ratio). Table 1. indicates the proliferative response of LNC was expressed as radioactive disintegrations per minute per lymph node (dpm/node) and as the ratio of HTdR incorporation by test nodes relative to control nodes (T/C ratio). Despite variations in the choice of vehicle and test concentrations, in no instance did exposure to sulphanilic acid result in a positive response.Hence it can be concluded that the sulphanilic acid is not skin sensitizing.

 

It is further supported by an experimental study conducted  by European commission (Opinion on phenylbenzimidazole sufonic acid and its salts, 2006)on structurally similar read across substance 4-aminobenzoic acid (205-753-0)on female CBA/JHsd mice .The read across substances share high similarity in structure and log kow .Therefore, it is acceptable to derive information on skin sensitization from the analogue substance. Skin Sensitisation method, Local Lymph Node Assay (LLNA) was carried out to with 4-aminobenzoic acid to study the skin sensitizing potential.To study the sensitizing potential 4 – 5 female mice ofCBA/Ca or CBA/JHsd strain, 6-12 weeks old were treated with4-aminobenzoic acid in 4:1 acetone/olive oil in concentrations: 0 (control) 0.5, 1.0, 2.5, 5.0, and 10.0% ondorsum of both ears daily for 3 (lab. A, B and E) or 4 (lab. C and D) consecutive days followed by rest for 2 days (lab. A, B and E) or no rest (lab. C and D) prior to analyses.On day 6 (lab. A, B and E) or 5 (lab. C and D), the mice were injected intravenously with 3H-TdR(or 125 IUdR for lab. E). Five hours later the mice were sacrificed, and the auricular lymph nodes were excised. Mechanical disaggregation through 200-mesh stainless steel gauze, wash with excess of PBS, precipitation with 5% TCA (4°C). Transferred to 10 ml scintillation fluid (Optiphase MP). Lab A and B pooled the lymph nodes for each group (pooled treatment approach), and lab. C, D and E analysed the lymph nodes from individual mice (individual animal approach).Isotope incorporation parameter approach was used to study the positive response. 4-aminobenzoic acid induced no increase in isotope incorporation, relative to vehicle control, Hence the 4-aminobenzoic acid is not sensitizing to mice.

Thus based on the above predictions on3,5 Diaminobenzoic acid (535-87-5)as well as its read across substances and applying weight of evidence, it can be concluded that3,5 Diaminobenzoic acidis not a skin sensitizer. Thus comparing the above annotations with the criteria of CLP regulation,3,5 Diaminobenzoic acid (535-87-5)can be considered as not classified for skin sensitization effects.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Thus comparing the above annotations with the criteria of CLP regulation,3,5 Diaminobenzoic acid (535-87-5)can be considered as not classified for skin sensitization effects.