(3E)-3-[[4-(2-carboxyethylcarbamoyl)phenyl]hydrazinylidene]-6-oxocyclohexa-1,4-diene-1-carboxylic acid

Endpoint summary

Description of key information

In vitro skin and eye irritation studies performed in accordance with GLP and recommended guidelines, have shown that Balsalazide acid is not a skin or eye irritant.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14th June 2018 - 17th July 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch: 0400

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

The EpiDerm Skin Model is a well-established organotypic, three-dimensional model of the human epidermis and is used for in vitro experiments since many years. It is known for its similarity to human skin.

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: MatTek
- Tissue lot number: 28623

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 ± 1°C
- Temperature of post-treatment incubation (if applicable): 37 ± 1°C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: The tissues were gently rinsed about 20 times with PBS (phosphate buffered saline). Excess PBS was removed by gently shaking the insert and blotting the bottom with blotting paper.
- Observable damage in the tissue due to washing: None reported

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 300 µL of pre-warmed MTT solution was used
- Incubation time: 3 hours
- Spectrophotometer: Plate spectrophotometer
- Wavelength: 570 nm

PREDICTION MODEL / DECISION CRITERIA
- The test substance is considered to be corrosive to skin if the viability after 3 minutes exposure is less than 50% or if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is less than 15%.]
- The test substance is considered to be non-corrosive to skin if the viability after 3 minutes exposure is greater than or equal to 50% and the viability after 1 hour exposure is greater than or equal to 15%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Concentration (if solution): 25 mg + 25 μL H2O

NEGATIVE CONTROL
- Concentration (if solution): 50 μL distilled water

POSITIVE CONTROL
- Concentration (if solution): 50 μL 8 N KOH

Duration of treatment / exposure:

3 min and 60 min exposure time

Duration of post-treatment incubation (if applicable):

3 hours

Number of replicates:

The test was performed on a total of 4 tissues per dose group, 2 replicates for each treatment

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 minutes treatment

Value:

112.9

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

60 minutes treatment

Value:

84.8

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

- OTHER EFFECTS:
- Visible damage on test system: None reported
- Direct-MTT reduction: The test material showed no non-specific MTT- reducing.
- Colour interference with MTT: The test item showed water-colouring potential in Aqua dest. and in isopropanol in the range of 570 ± 30 nm. Therefore, additional viable tissue controls were treated with the test item to determine the non-specific colour (NSCliving) and the results were corrected to the true MTT metabolic conversion (TODTT).

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes - mean absolute OD570 nm for 3 min experiment: 1.651; mean absolute OD570 nm for 60 min experiment: 1.896
- Acceptance criteria met for positive control: Yes - mean relative tissue viability for 60 min experiment: 6.6%
- Acceptance criteria met for variability between replicate measurements: Yes - CV: 4.4 - 12.8%

Table 1: Results of 3 min experiment

Name	Negative control		Test item		Positive control
Tissue	1	2	1	2	1	2
Absolute OD570	1.585	1.687	1.926	1.819	0.192	0.161
	1.596	1.716	1.920	1.782	0.195	0.161
	1.617	1.705	1.896	1.805	0.195	0.168
OD570 - Blank Corrected	1.540	1.642	1.882	1.774	0.148	0.116
	1.551	1.671	1.875	1.737	0.150	0.116
	1.572	1.660	1.851	1.760	0.150	0.123
Mean OD570 of 3 Aliquots (Blank Corrected)	1.554	1.658	1.869	1.757	0.149	0.118
SD OD570 of 3 Aliquots	0.016	0.015	0.016	0.019	0.002	0.004
Total Mean OD570 of 2 Replicate Tissues (Blank Corrected)	1.606*		1.813		0.134
TODTT			1.813
SD OD570 of 2 Replicate Tissues	0.073		0.080		0.022
Mean Relative Tissue Viability [%]	100.0		112.9		8.3
Mean Relative Tissue Viability [%] - NSCliving Corrected	-		112.9		-
Coefficient Of Variation [%]***	4.6		4.4		16.3

* corrected mean OD570 of the negative control corresponds to 100% absolute tissue viability.

*** coefficient of variation (CV) (in the range of 20 – 100% viability) between two tissues treated identically is

≤ 30%.

Table 2: Results of 60 min experiment

Name	Negative control		Test item		Positive control
Tissue	1	2	1	2	1	2
Absolute OD570	2.007	1.778	1.747	1.476	0.187	0.148
	1.996	1.803	1.760	1.475	0.187	0.151
	1.987	1.803	1.763	1.468	0.186	0.148
OD570- Blank Corrected	1.962	1.733	1.702	1.431	0.142	0.104
	1.951	1.758	1.715	1.430	0.142	0.106
	1.942	1.759	1.719	1.423	0.141	0.104
Mean OD570of 3 Aliquots (Blank Corrected)	1.952	1.750	1.712	1.428	0.142	0.105
SD OD570of 3 Aliquots	0.010	0.015	0.009	0.004	0.001	0.002
Total Mean OD570of 2 Replicate Tissues (Blank Corrected)	1.851		1.570		0.123
TODTT	-		1.570		-
SD OD570of 2 Replicate Tissues	0.143		0.201		0.026
Mean Relative Tissue Viability [%]	100.0		84.8		6.6**
Mean Relative Tissue Viability [%] - NSClivingCorrected	-		84.6		-
Coefficient Of Variation [%]***	7.7		12.8		21.2

* corrected mean OD570 of the negative control corresponds to 100% absolute tissue viability.

** mean relative tissue viability of the 60 min positive control < 15%,

*** coefficient of variation (CV) (in the range of 20 – 100% viability) between two tissues treated identically is

≤ 30%

Table 3: Result of the NSC_living control at 3 min

NSCliving	TVT		Negative control
Tissue	1	2	1	2
absolute OD570 - values	0.047	0.047	1.585	1.687
	0.049	0.049	1.596	1.716
	0.048	0.048	1.617	1.705
absolute OD570- Blank corrected values	0.002	0.002	1.540	1.642
	0.005	0.004	1.551	1.671
	0.003	0.003	1.572	1.660
mean OD570 (mean of 3 aliquots)	0.003	0.003	1.554	1.658
total mean OD570 (mean of replicate tissues)	0.003		1.606
SD OD570 (of the 2 replicate tissues)	0.000		0.073
NSCliving [%]	0.2		-
Relative Tissue Viability [%]	-		96.8	103.2
Mean Relative Tissue Viability [%]	-		100.0
SD Tissue Viability [%]	-		4.6
CV [% Viabilities]	-		4.6

Table 4: Result of the NSC_living control at 60 min

NSCliving	TVT		Negative control
Tissue	1	2	1	2
absolute OD570 - values	0.048	0.048	2.007	1.778
	0.053	0.050	1.996	1.803
	0.048	0.048	1.987	1.803
absolute OD570- Blank corrected values	0.003	0.003	1.962	1.733
	0.008	0.005	1.951	1.758
	0.003	0.003	1.942	1.759
mean OD570 (mean of 3 aliquots)	0.005	0.003	1.9552	1.750
total mean OD570 (mean of replicate tissues)	0.004		1.851
SD OD570 (of the 2 replicate tissues)	0.001		0.143
NSCliving[%]	0.2		-
Relative Tissue Viability [%]	-		105.4	94.6
Mean Relative Tissue Viability [%]	-		100.0
SD Tissue Viability [%]	-		7.7
CV [% Viabilities]	-		7.7

The test item showed no non-specific MTT-reducing but water-colouring potential in Aqua dest. And in isopropanol in the range of 570 ± 30 nm . Therefore, additional viable tissue controls were treated with the test item to determine the non-specific colour (NSC_living) and the results were corrected to the true MTT metabolic conversion (TOD_TT).

  

As NSC_livingwas ≤ 5% relative to the negative control of living epidermis, no correction of the results was necessary.

The test item showed no corrosive effects. The mean relative tissue viability (% negative control) was ≥50% (112.9%) after 3 min treatment and ≥15% (84.8%) after 60 min treatment.

The controls confirmed the validity of the study. The mean OD_570nmof the two negative control tissues was ≥0.8 and ≤2.8 for each exposure period. The mean relative tissue viability (% negative control) of the positive control was < 15% (1.896%) after 60 min treatment. The coefficient of variation (CV) (in the range of 20 – 100% viability) of replicate tissues of all dose groups was ≤30% (4.4% - 12.8%).

Interpretation of results:

GHS criteria not met

Conclusions:

The test item showed no corrosive effects and is therefore classified as 'non-corrosive'.

Reference 2

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 November - 21 December 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

28 July 2015

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Version / remarks:

6 July 2012

Qualifier:

according to guideline

Guideline:

other: L'Oreal Standard Operating Procedure:"EpiSkin Test Method";-ECVAM Skin Irritation Validation Study- Validation of the EpiSkin Test Method for the Prediction of Acute Skin Irritation of Chemicals

Version / remarks:

Version 1.8, Feb-2009

Qualifier:

according to guideline

Guideline:

other: ECVAM DB-ALM Protocol No. 131 "EpiSkin Skin Irritation test "

Version / remarks:

9 June 2012

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Test material: Balsalazide acid
Batch No.: 0400
Description: solid, deep orange, crystalline powder
Storage conditions: Room temperature

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: Adult donors

Justification for test system used:

This test uses the EPISKIN-SM™ reconstructed human epidermis model (SkinEthic) which consists of normal human epidermal keratinocytes (NHEK) and therefore represents in vitro the target organ of the species of interest and closely mimics the biochemical and physiological properties of the upper parts of the human skin, i.e. the epidermis.

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKIN-SM™
- Lot No.: 18-EKIN-051
- Expiry date: 24 December 2018

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: Room temperature
- Temperature of post-treatment incubation: 37 ± 1°C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: The tissues were washed with DPBS to remove any residual test item and excess DPBS was removed by blotting bottom with blotting paper.
- Observable damage in the tissue due to washing: None reported

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 2 mL of 0.3 mg/mL MTT
- Incubation time: 3 hours ± 5 minutes
- Spectrophotometer: Plate spectrometer
- Wavelength: 570 nm
- Filter: Yes
- Filter bandwidth: ± 30 nm

NUMBER OF REPLICATE TISSUES: 3

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
- Not required

PREDICTION MODEL / DECISION CRITERIA
- The test item is considered to be irritant to skin if the tissue viability after 15 min of exposure and 42 h of post-incubation is less or equal to 50%.
- The test substance may be considered as non-irritant to skin if the tissue viability after exposure and post-treatment incubation is higher than 50%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

yes, concurrent MTT non-specific colour control

Amount/concentration applied:

TEST MATERIAL
- 10 ± 2 mg + 5 µL aqua dest.

NEGATIVE CONTROL
- 10 µL Dulbecco's Phosphate Buffering Saline

POSITIVE CONTROL
- 10 µL 5% sodium dodecyl sulfate

The test was performed on a total of 3 tissues per dose group.

Duration of treatment / exposure:

15 ± 0.5 minutes

Duration of post-treatment incubation (if applicable):

42 ± 1 hour plus 3 hour MTT incubaton period

Number of replicates:

Three

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Mean

Value:

98.5

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

The mixture of 10 mg test item per 2 mL MTT medium showed no reduction of MTT as compared to the solvent. The mixture did not turn blue/purple. Therefore, NSMTT (non-specific reduction of MTT) equalled 0%.

The mixtures of 10 mg of the test item per 90 µL aqua dest. and per 90 µL isopropanol showed colouring detectable by unaided eye-assessment but the chemical in water and/or isopropanol did not absorb light in the range of 570 ± 30 nm. Therefore, NSCliving (non-specific colour of additional viable tissues) equalled 0%.

The test item showed no non-specific reduction of MTT and no relevant colouring potential after mixture with aqua dest. and with isopropanol. Therefore, no additional controls for correction of possible false-negative results were necessary.

The test item showed no irritant effects. The mean relative tissue viability (% negative control) was > 50% (98.5%) after 15 min treatment and 42 h post-incubation.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes: Mean Absolute OD570 nm = 0.967
- Acceptance criteria met for positive control: Yes: Mean relative viability (%) = 3.4
- Acceptance criteria met for variability between replicate measurements: Yes: Max. SD of % viability (%) = 10.1
- Range of historical values if different from the ones specified in the test guideline:

Table 1: Result of the Test Item Balsalazide acid

Name	Negative Control			Positive Control			Test Item
Replicate Tissue	1	2	3	1	2	3	1	2	3
Absolute OD570	0.856	0.975	1.043	0.072	0.076	0.067	0.946	0.908	1.059
	0.877	0.992	1.060	0.070	0.081	0.070	0.961	0.898	0.950
Mean Absolute OD570	0.967****			0.073			0.954
OD570(Blank Corrected)	0.815	0.934	1.002	0.031	0.035	0.026	0.905	0.867	1.018
	0.836	0.951	1.019	0.029	0.040	0.029	0.920	0.857	0.909
Mean OD570of the Duplicates (Blank Corrected)	0.825	0.943	1.011	0.030	0.037	0.027	0.913	0.862	0.964
Total Mean OD570of the 3 Replicate Tissues (Blank Corrected)	0.926*			0.032			0.913
SD of Mean OD570of the Duplicates (Blank Corrected)	0.094			0.005			0.051
Relative Tissue Viability [%]	89.1	101.8	109.1	3.2	4.0	3.0	98.5	93.0	104.0
Mean Relative Tissue Viability [%]	100.0			3.4**			98.5
SD of Relative Tissue Viability [%]***	10.1			0.6			5.5
CV [% Viabilities]	10.1			16.4			5.6

*                 Corrected mean OD₅₇₀of the negative control corresponds to 100% absolute tissue viability.

** Mean relative tissue viability of the three positive control tissues is£ 40%

  

***          Standard deviation (SD) obtained from the three concurrently tested tissues is≤ 18%.

****        The mean absolute OD₅₇₀of the negative control is≥ 0.6 and ≤ 1.5.

 

Interpretation of results:

GHS criteria not met

Conclusions:

In this study under the given conditions the test item showed no irritant effects. The relative mean tissue viability after 15 min of exposure and 42 h post-incubation was > 50%. The test item, balsalazide acid, is therefore classified as “non-irritant” to skin.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28 November 2018 - 13 February 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Test material: Balsalazide acid
Batch No.: 0400
Description: solid, deep orange, crystalline powder
Storage conditions: Room temperature

Details on test animals or tissues and environmental conditions:

- Tissue source: The assay used isolated corneas obtained as a by-product from animals freshly slaughtered at the abattoir A. Moksel AG, Buchloe, Germany.

Vehicle:

physiological saline

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 750 µL of the test item preparation or the control substance
- Concentration: The test item was suspended with physiological saline 0.9% NaCI to give a 20% concentration.

Duration of treatment / exposure:

4 hours ± 5 minutes incubation at 32 ± °C

Duration of post- treatment incubation (in vitro):

90 minutes at 32 ± 1°C

Number of animals or in vitro replicates:

Three corneas were tested for the test item, negative control and positive control.

Details on study design:

SELECTION AND PREPARATION OF CORNEAS
On the test day, fresh eyes were collected from the slaughterhouse and were transported in HBSS containing Pen/Strep on ice to the laboratories. Immediately after arrival of the eyes, cornea preparation was initiated.
The eyes were carefully examined for defects and any defective eyes were discarded.
The tissue surrounding the eyeball was carefully pulled away and the cornea was excised leaving a 2 to 3 mm rim of sclera. The isolated corneas were stored in a petri dish containing HBSS.

QUALITY CHECK OF THE ISOLATED CORNEAS
Before the corneas were mounted in corneal holders with the endothelial side against the 0-ring of the posterior chamber, they were visually examined for defects and any defective cornea were discarded.

NUMBER OF REPLICATES
Three replicates per test substance or control.

NEGATIVE CONTROL USED
Physiological saline 0.9% NaCI

POSITIVE CONTROL USED
Imidazole 20% in physiological saline 0.9% NaCI

APPLICATION DOSE AND EXPOSURE TIME
750 µL of the test item preparation or the control substance was introduced into the anterior chamber (closed-chamber method). After 4 hours ± 5 minutes incubation at 32 ± 1 °C either the test substance or the control substance was removed.

TREATMENT METHOD: closed chamber

REMOVAL OF TEST SUBSTANCE
The epithelium was washed at least three times with MEM (minimum essential medium) (containing phenol red). Once the medium was free of test substance, the cornea was finally rinsed with complete RPMI (Roswell Park Memorial Institute) 1640 medium (without phenol red).

POST-EXPOSURE INCUBATION: The posterior chamber was refilled with fresh complete RPMI 1640 medium. 1 mL of a 5 mg/mL sodium fluorescein solution was added to the anterior chamber and the corneas were incubated for 90 minutes at 32 ± 1°C.

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity : The change in opacity for each cornea was calculated by subtracting the initial opacity reading from the final opacity reading. These values were corrected by subtracting from each the average change in opacity observed for the negative-control corneas. The mean opacity value for each treatment was calculated by averaging the corrected opacity values of each cornea for a given treatment.
- Corneal permeability: passage of sodium fluorescein dye measured with the aid of UV/VIS spectrophotometry (OD490)
- Others: After the initial incubation period, each cornea was observed visually and pertinent observations were recorded.

SCORING SYSTEM: In Vitro Irritancy Score (IVIS)
IVIS = mean opacity value + (15 x mean permeability OD490 value)

DECISION CRITERIA: As indicated in the guideline

Irritation parameter:

in vitro irritation score

Run / experiment:

Mean

Value:

0.27

Vehicle controls validity:

not examined

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

The mean in vitro irritation score for Balsalazide acid was 0.27.

OTHER EFFECTS:
- Visible damage on test system: All 3 corneas treated with Balsalazide acid showed a slight yellowish discolouration of the edges of the tissue.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: The negative control responses in the 2nd experiment resulted in opacity and permeability values that were less than the established upper limits for background bovine corneas treated with the respective negative control.
- Acceptance criteria met for positive control: In the 2nd experiment the in vitro Irritation score obtained with the positive ontrol fell within the two Standard deviations of the current historical mean and therefore this assay was considered to be valid.
- Range of historical values if different from the ones specified in the test guideline: Mean IVIS value (MV) = 122.15; Standard deviation (SD) = 18.00; MV-2xSD = 86.16; MV+2xSD = 158.14 (number of measurements = 40)

Due to the fact that the IVIS of the positive control did not fall within the two Standard deviations of the current historical mean in the 1st experiment, this experiment was considered to be not valid according to the study acceptance criteria stated in the guideline. Therefore, the experiment was repeated and all data reported here refers to the second experiment.

Table 1: Opacity results

Cornea No.	Test item	Initial opacity	Final opacity	Change of opacity value	Corrected opacity value
1	Negative control	2.21	3.16	0.95
2		2.06	2.35	0.29
3		2.31	2.68	0.36
MV		2.19	2.73	0.53
4	Positive control	2.97	88.54	85.56	85.03
5		3.16	99.17	96.01	95.48
6		2.79	90.25	87.46	86.93
MV		2.97	92.65	89.68	89.15
7	Test item	0.79	1.40	0.61	0.08
8		2.71	3.50	0.79	0.25
9		0.65	1.67	1.02	0.49
MV		1.38	2.19	0.81	0.27

MV = mean value

 

Table 2: Permeability results:

Cornea No.	Test item	OD490	Corrected OD490 value
1	Negative control	0.009
2		0.014
3		0.023
MV		0.015
4	Positive control	1.378	1.363
5		2.000	1.985
6		2.185	2.170
MV		1.854	1.839
7	Test item	0.010	-0.005
8		0.027	0.012
9		0.009	-0.006
MV		0.015	0.000

MV = mean value

 

Table 3: In vitro irritation score

Cornea No.	Test item	Corrected opacity value	Corrected OD490 value	IVIS
1	Negative control	0.95	0.009
2		0.29	0.014
3		0.36	0.023
MV		0.53	0.015	0.76
4	Positive control	85.03	1.363
5		95.48	1.985
6		86.93	2.170
MV		89.15	1.839	116.73
7	Test item	0.08	-0.005
8		0.25	0.012
9		0.49	-0.006
MV		0.27	0.000	0.27

MV = mean value

Interpretation of results:

GHS criteria not met

Conclusions:

According to the evaluation criteria of the test guideline, the test item, Balsalazide acid, does not require classification as corrosive to eyes or as an eye irritant.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The in vitro skin corrosion and skin and eye irritation studies performed in accordance with OECD Guidelines 431, 439 and 437, respectively, show that Balsalazide acid is not corrosive or irritating. Therefore, in accordance with Regulation (EC) No. 1272/2008, Balsalazide acid does not require classification as corrosive or as a skin or eye irritant.