2-methyl-p-phenylenediamine sulfate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

weight of evidence

Study period:

2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable calculated/extrapolated data

Data source

Reference

Reference Type:

other: Expert opinion

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

no guideline required

Principles of method if other than guideline:

To assess the acute inhalational toxicity of toluene-2,5-diamine (free base and sulphate salt), a kinetic based calculation was done. The kinetic data were derived from various kinetic studies, and the details of the test methods and the results are provided in this summary (refer to executive summary for details). The derived data were consistent with the determined acute toxicity values (derived by in-vivo studies) from p-phenylenediamine, the most appropriate analogue for toluene-2,5-diamine.

Test type:

other: Estimated data by calculation

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-methyl-p-phenylenediamine sulfate

EC Number:

210-431-8

EC Name:

2-methyl-p-phenylenediamine sulfate

Cas Number:

615-50-9

Molecular formula:

C7H10N2.H2O4S

IUPAC Name:

2-methylbenzene-1,4-diamine; sulfuric acid

Constituent 2

Reference substance name:

toluene-2,5-diamine sulfate

IUPAC Name:

toluene-2,5-diamine sulfate

Constituent 3

Reference substance name:

2-methyl-p-phenylenediamine

EC Number:

202-442-1

EC Name:

2-methyl-p-phenylenediamine

Cas Number:

95-70-5

Molecular formula:

C7H10N2

IUPAC Name:

2-methylbenzene-1,4-diamine

Constituent 4

Reference substance name:

toluene-2,5-diamine

IUPAC Name:

toluene-2,5-diamine

Details on test material:

- Name of test material: TOLUENE-2,5-DIAMINE (free base and sulphate salt) is 1,4-phenylene diamine with a single methyl substituent on the benzene ring. Therefore, it is a member of the p-phenylenediamine family.

Results and discussion

Effect levels

Effect levels 1

Sex:

not specified

Dose descriptor:

LC50

Effect level:

0.99 mg/L air

Based on:

other: kinetic based calculation

Exp. duration:

4 h

Remarks on result:

other: The calculated inhalational LC50 of 0.99 mg/L for toluene-2,5-diamine is comparable to the determined value for p-phenylenediamine (0.92 mg/L)

Effect levels 2

Sex:

not specified

Dose descriptor:

LC50

Effect level:

1.77 mg/L air

Based on:

other: kinetic based calculation

Exp. duration:

4 h

Remarks on result:

other: The calculated inhalational LC50 of 1.77 mg/L for toluene-2,5-diamine sulphate salt is comparable to the determined value for p-phenylenediamine (0.92 mg/L)

Applicant's summary and conclusion

Interpretation of results:

Category 4 based on GHS criteria

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

Based on the available acute oral toxicity and kinetic data for toluene-2,5-diamine, the extrapolated acute inhalation toxicity (4 h, LC50) of toluene-2,5-diamine was 0.99 mg/L for the free base and 1.77 mg/l for the sulphate salt. This value is comparable to the determined value for p-phenylenediamine (0.92 mg/L).

Executive summary:

To assess the acute inhalational toxicity of toluene-2,5-diamine (free base and sulphate salt) , a kinetic based calculation was done. The kinetic data were derived from various kinetic studies, and the details of the test methods and the results are provided in the SCCS Opinion 1479/12, 26 – 27June 2012.In addition, the calculated data for toluene-2,5-diamine (free base and the sulphate salt) were compared with those of the most appropriate analogue, the p-phenylenediamine (refer to below table).

COLIPA Number	Chemical Name	CAS Number	Acute Toxicity
			Oral LD50	Dermal LD50	Inhalation LC50
Colipa No. A005	Toluene-2,5-Diamine	95-70-5 (free base)	102 mg/kg bw (rat)	> 2000 mg/ kg bw (rat, extrapolated)	0.99 mg/l,  (4h, rat, extrapolated)
Colipa No. A005	Toluene-2,5-diaminesulphate	615-50-9	183 mg/kg bw (rat, extrapolated)	> 2000 mg/kg bw (rat, extrapolated)	1.77 mg/L,  (4h, rat, extrapolated)
Colipa No. A007	p-Phenylenediamine	106-50-3 (free base)	80-100 mg/kg bw (rat)	> 7940 mg/kg bw (male/female rabbit)	0.92 mg/l air (4 h ,rat)

Studies used for the determination of acute toxicity of TOLUENE-2,5-DIAMINE:

Conversion Factor between the free base and the sulphate salt:

The toxic potential of both forms of 2 Toluene-2,5-diamine is attributable to the free base component. Therefore, study results derived with one of the two forms of Toluene-2,5-diamine, namely the free base or the sulphate salt, can be converted to the other form by applying a conversion factor that is related to the molecular weight and content of the free base in each form.

Molar Mass_sulfate: 218.23 g/mol

Molar Mass_{free base}: 122.71 g/mol

Conversion factor free base → sulphate = 1.79

Conversion factor sulphate →free base = 0.56

Acute Oral Toxicity study result

LD₅₀oral: 102 mg/kg bw in the rat (CFY strain); “The acute median lethal oral dose was calculated to be 102 mg/kg bw (95% confidence limits of 69-152 mg/kg bw)”.The study was carried out with the free base.

LD₅₀oral=102 mg/kg bw (Toluene-2,5-Diamine)

Conversion factor free base→sulphate = 1.78628

LD₅₀oral=182 mg/kg bw (Toluene-2,5-Diamine Sulphate)

Toxicokinetic study results in Sprague Dawley rats:

Dose levels:

IV: 2.5 mg/kg bw

Oral: 2.5, 25 mg/kg bw

Dermal:0.5 mg/cm² equal to 33.3 mg/kg bw

Bioavailability, assuming 100% bioavailability IV

Oral dosing: 69%

Dermal dosing: 2%

The studies are summarized as follows in SCCS 1479/12:

“In toxicokinetic studies with Sprague-Dawley rats the comparison of AUCs showed differences between oral (25 mg/kg bw: 112 mg_eqx h/l) and dermal application (33 mg/kg bw in formulation: 2.27 mg_eqx h/l). Following 2.5 mg/kg bw the AUC was 8.53 mg_eqx h/l. The bioavailability (derived from comparison to iv administration) after oral dosing of 10 mg/kg bw was 69% while 2% bioavailability was found after dermal administration in a formulation.”The Studies were carried out with the sulphate salt.

This summary provides calculation ofextrapolation of the acute inhalation toxicity of toluene-2,5-diamine. The summary of calculation of extrapolation of the acute dermal toxicity is provided under section 7.2.3 of IUCLID.

 

Extrapolation of the acute inhalational toxicity of TOLUENE-2,5-DIAMINE:

Required maximum exposure concentration to test material (OECD 403):           5 mg/L

Assumed body weight of the rat for the calculation:                                            250 g

Respiratory volume of the rat:                                                                            0.074 L/min

Required duration (OECD 403):                                                                          4 h

Ventilation in 4 hours                                                                              0.074 L/min x 60 min x 4 hour = 17.76L

Toluene-2,5-diamine LD₅₀oral = 102 mg/kg bw in the ratwith the free base

Calculation:

Maximum achievable exposure regarding required 5 mg/L for 4 hours (OECD 403):

Exposure during 4 hours:17.76 L x 5 mg/L = 88.8 mg/rat

88.8 mg/0.250 kg bw = 355 mg/kg bw maximum achievable exposure

Oral Bioavailability = 69% (at 25 mg/kg bw, using the data from the toxicokinetic study in Sprague Dawley rats)

Inhalation Bioavailability: Assumed to be 100%

Determination of the correction factor oral vs. inhalation route:

69% oral vs. 100% inhalation = 0.69

LC_{50 calc}inhal. free base: 102 mg/kg bw x 0.250 kg bw x 0.69/17.76 L = 0.99 mg/L

LC_{50 calc}inhal. free base: 0.99 mg/L x 1.79 (conversion free base to sulphate) = 1.77 mg/L

LC₅₀inhal. forp-phenylenediamine = 0.92 mg/L

LC_{50 calc}inhal. for toluene-2,5-diamine     = 0.99 mg/L free base

LC_{50 calc}inhal.Toluene-2,5-diamine          = 1.77 mg/l sulphate salt

 

 

The calculated LC₅₀for toluene-2,5-diamine, namely 0.99 mg/L for the free base and 1.77 mg/L for the sulphate saltcomparable to the determined value forp-phenylenediamine (0.92 mg/L)

The calculated inhalation toxicity value for toluene-2,5-diamine is in the same order of magnitude (0.99 mg/lfor the free base and 1.77 mg/L for the sulphate salt) as the official classification of Acute Tox Cat 4; H332 in Annex VI of the CLP regulation which is being applied in case of 1 mg/L<LC₅₀≤5 mg/L (for dusts/mists).

ASSESSMENT OF VALIDITY:

Since the Weight of Evidence Approach (WoE) used was considered as sufficiently robust to determine the acute inhalation toxic potential of toluene-2,5-diamine, the performance of an animal test for hazard identification purposes was considered to be not justified.

In addition the completion of acute toxicity studies on toluene-2,5-diamine as an ingredient used in cosmetic products would not be considered to comply with the EU regulations regarding animal testing. Furthermore, applying WoE complies with the REACH regulation to avoid animal testing. The validity of the WoE/extrapolation approach used in order to estimate the acute toxicity potential of toluene-2,5-diamine by inhalation route was finally confirmed by the comparison of the extrapolated values on toluene-2,5-diamine with experimental values obtained on the primary member of the p-phenylenediamine family, p-phenylenediamine.

In conclusion, the extrapolated acute inhalation toxicity (4 h, LC50) of toluene-2,5-diamine was 0.99 mg/Lfor the free base and 1.77 mg/L for the sulphate salt. This value is comparable to the determined value for p-phenylenediamine (0.92 mg/L)