2-methyl-p-phenylenediamine sulfate

Endpoint summary

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Absorption rate - oral (%):

69

Absorption rate - dermal (%):

2

Additional information

Basic toxicokinetics

 

By dermal route:Two in vivo studies of reliability 1 or 2 were available for evaluation of absorption. One ADME study of reliability 1, and one pharmacokinetics study of reliability 1.

The toxicokinetics of Toluene-2,5-diamine sulphate through dermal route was evaluated following OECD Guidelines 417 (Toxicokinetics) and OECD Guideline 427 (Percutaneous Absorption: in vivo methodFemale Sprague-Dawley, received The dose levels of [ring-14C (U)]-toluene-2,5-diamine sulphate applied to groups 1-6 were:

2.1 mg/mL; 21 μg/cm2 - dosing surface area 20 cm2; 1.4 mg/kg bw

7.7 mg/mL; 75 μg/cm2 - dosing surface area 20 cm2; 6.0 mg/kg bw

24 mg/mL; 224 μg/cm2 - dosing surface area 20 cm2; 19.5 mg/kg bw

72 mg/mL; 734 μg/cm2 - dosing surface area 20 cm2; 63.2 mg/kg bw

7.3 mg/mL; 80 μg/cm2 - dosing surface area 5 cm2; 1.5 mg/kg bw

72 mg/mL; 677 μg/cm2 - dosing surface area 5 cm2; 13.3 mg/kg bw

The test material was applied for 30 min. The blood samples for measurement of radioactivity were collected at 0.5, 1, 2, 3, 4, 8, 24, 48 h points.

Plasma samples separated from the blood samples were analyzed for radioactivity

Dermal absorption was rapid with tmax reached at 0.5 - 1 h after dosing in all groups. Mean plasma AUC values of Toluene-2,5-diamine sulphate increased proportionally with increasing concentration after dermal application in the concentration range tested.(Van De Kerkhof E G, 2009).

The purpose of this study was to determine the absorption and excretion of p-toluenediamine, after topical application of two formulations containing (Me-14C) p-toluenediamine. The healthy adult human (male) were selected and grouped randomly into 2 groups containing 5/ group. The formulation I & II contained 50% of deionized water and hydrogen peroxide (6%), respectively. The 45 g of formulations containing 371 mg test substance were applied to hair bearing scalp for 30 min.

For formulation I, the absorption was 5% of the applied dose while for formulation II the absorption was 1.4% of the applied dose. The absorption rates of toluene-2,5-diamine sulfate were 71 ± 9.26 μgeq/cm2 (formulation I, non-oxidative conditions) and 20 ± 2.02 μgeq/cm2 (formulation II, oxidative conditions).

In terms of absolute quantities, and by reference to the dose of each formulation containing 371 mg test substance, indicate absorption of around 18 mg with formulation I and 5 mg with formulation II.

The absorption and excretion of p-(Me-14C) p-toluenediamine in formulation I was higher than formulation II, when applied topically to human subjects for 30 min. (Aylward M & Protheroe D, 1981)

The absorption, distribution, metabolism and excretion of14C-Toluene-2,5-diamine sulphateafter dermal administration was determined by following the OECD guideline 417 (Toxicokinetics).

The study was designed to study the fate of 14C-toluene-2,5-diamine sulphate in female Wistar rats after dermal administration at 33 mg/kg-bw (0.1 mL, 50mg/mL) in Groups 3 and 6. Group 3 and 6 contained 4 and 6 animals each, group 3 was used for ADME study and group 6 was used for toxicokinetic study.  All test formulations were prepared in water: acetone (1:1) (milli-Q), immediate prior to administration.The dermal absorption of 14C-toluene-2,5-diamine sulphate was moderate and mainly excreted through urine. N-acetylation was the most important metabolic reaction for 14C-toluene-2,5-diamine sulphate. (Wenker M A M., 2005).

 

By oral route:One toxicokinetics study of reliability 2 was available, one ADME of reliability 1, and one pharmacokinetics study of reliability 1.

The toxicokinetic parameters of [14C] 2 -methyl-p-phenylenediamine sulphate (in formulations) were determined by dosing to male and female rats, once orally by gavage, following OECD guideline 417 (Toxicokinetic).Male and female (Sprague-Dawley, cannulated) rats were used in study. Group I: 0 mg/kg bw (Control group to determine background radioactivity concentrations) Group II: 5 mg/kg bw (0.5 mg/mL) Group III: 10 mg/kg bw (1 mg/mL). Radiolabelled 2-methyl-p-phenylenediamine sulphate [14C] (2, 5-diamine toluene-sulfate) when administered to male and female Sprague-Dawley at 5 and 10 mg/kg bw showed a rapid absorption following an oral dose. (Rodrigue M E, 2010).

The pharmacokinetics of Toluene-2,5-diamine sulphate (Haarbraun) was determined following the OECD guideline 417 (Toxicokinetics). Female Sprague Dawley (Charles River, Sulzfeld, Germany, 9-10 wk old) rats were used. 6 animals/dose group were treated once orally (5 mL/kg bw) with doses of 2.5 (Group 1) and 25 (Group 2) mg/kg bw. The formulations of test material were prepared in millQ with nominal concentrations of 0.5 and 2.5 mg/mL for Group 1 and 2, respectively; with specific activity of 0.4 MBq/mg in each formulation. NaOH was added to formulation to increase the solubility of test material in formulation. 14C-Toluene-2,5-diamine sulphate (Haarbraun) was absorbed and excreted quickly after oral administration, following linear kinetics at the dose levels tested. (Wenker, 2005)

 

The absorption, distribution, metabolism and excretion of 14C-Toluene-2,5-diamine sulphateafter oral administration was determined by following the OECD guideline 417 (Toxicokinetics). The study was designed to study the fate of 14C-toluene-2,5-diamine sulphate in femaleWistar Kyotorats after oral administration at different dose levels: 2.5 mg/kg bw and 25 mg/kg bw. Four groups of rats were used in the study: Group 1 and 2 (animal number =4) for the mass balance and Group 4 and 5 (animal number =6) for the toxicokinetics. 14C-Toluene-2,5-diamine sulphate when administered orally was extensively absorbed, readily distributed into all organs, extensively metabolized and excreted via the urine and faeces. (Wenker M A M., 2005).

14C-Toluene-2,5-diamine sulphate (Haarbraun) was absorbed and excreted quickly after oral administration, following linear kinetics at the dose levels tested. (Wenker M A M., 2005).

By Intravenous route:One ADME study of reliability 1, and one pharmacokinetics study of reliability 1.

The absorption, distribution, metabolism and excretion after intravenous administration of 14C-Toluene-2,5-diamine sulphate was determined according to the OECD guideline 417 (Toxicokinetics). Two groups of female Wistar Kyoto rats (Charles River, Sulzfeld, Germany) were used in the study: Group 1 (animal number =4) for the mass balance study and group 2 (animal number =6) for the toxicokinetics study. 14C-Toluene-2,5-diamine sulphate when administered intravenously was readily distributed into all organs, extensively metabolized and excreted via the urine and faeces. (Wenker M A M., 2005).

The pharmacokinetics of Toluene-2,5-diamine sulphate (Haarbraun) after single intravenous administration was determined by following the OECD guideline 417 (Toxicokinetics). Female Sprague Dawley rats (Charles River 9 wk old) were used in study. Six rats per group were treated intravenously with dose of 2.5 mg/kg bw (2 mL, by tail vein) of formulation. The formulation was prepared in milliQ (nominal concentration: 1.25 mg/mL, specific activity: 4 MBq/mg).

Toluene-2,5-diamine sulphate (Haarbraun) was rapidly metabolized and therefore was difficult to detect in plasma when administered once intravenously to female Sprague Dawley rats.(Wenker M A M., 2005).

Two in vitro study of reliability 2 were available on metabolisation: The aim of one study was to investigate the metabolism of toluene-2,5-diaminein vitro using three different systems: a microsomal system, a recombinant Cytochrome P450 isozyme system, and a human hepatocyte system from four different donors.  The test material (10 or 100 µM ) was incubated with human liver microsomes, hepatocytes and recombinant cytochrome P450 isozymes for 20 min, 60 min and 240 min, respectively  A protein binding experiment was also performed to identify the potential for protein binding and the creation of a highly reactive metabolite which binds immediately to proteins. Toluene-2,5-diamine is acetylated in human hepatocytes. There was no evidence to suggest that toluene-2,5-diamine undergoes oxidative metabolism in human microsomes, by cytochrome P450 isoenzymes or in human hepatocytes. Toluene-2,5-diamine was acetylated in human hepatocytes. There was no evidence to suggest that toluene-2,5-diamine undergoes oxidative metabolism in human microsomes, by cytochrome P450 isoenzymes or in human hepatocytes. (Powrie R, 2005).

The aim of this study was to investigate the metabolism of toluene-2,5-diaminein vitro using three different systems: a microsomal system, a recombinant Cytochrome P450 isozyme system, and a human hepatocyte system from four different donors. 

Toluene-2,5-diamine is acetylated in human hepatocytes. There was no evidence to suggest that toluene-2,5-diamine undergoes oxidative metabolism in human microsomes, by cytochrome P450 isoenzymes or in human hepatocytes. The metabolic rate of the 2,5-diaminotoluene sulfate was extensive for human, rat and mouse primary hepatocytes. Under the conditions applied in this study, the test substance was extensively metabolized by N-acetylation in all three species, but mouse hepatocytes additionally revealed extensive hydroxylation of the 2,5-diaminotoluene sulfate (Krebsfanger N, 2003).

 

Dermal absorption

Nine in vitro studies were available for skin penetration (reliability 1).

A total of 3 test formulations/solutions were evaluated in this study. Formulation A : 21.9 mg (actual) of the formulation, containing 1.20 mg/cm2 of test substance was applied to topically to the horny layer of the skin for 30 min and subsequently washed off with Tween 20 and deionized water. The other 2 test formulation/solutions were: Formulation B: Typical hair dye formulation of pTD-sulfate with developer containing H2O2, 20.8 µg/cm2 (1.72% dose) of pTD-sulfate in a hair dye formulation without hydrogen peroxide was considered as biologically available (receptor fluid: 10.7 µg/cm2, remaining skin other than stratum corneum: 10.1 µg/cm2) in the cutaneous absorption (in vitro) study. Solution C: Aqueous solution of pTD-sulfate in ammonia. 42.0 µg/cm2 (3.94% dose) of aqueous solution of pTD-sulfate was considered as biologically available (receptor fluid: 13.3 µg/cm2, remaining skin other than stratum corneum: 28.6 µg/cm2) in the cutaneous absorption (in vitro) study. (Bornatowicz N, 2002)

2-methyl-1,4-benzenediamine sulfate (Haarbraun) when applied at a dose of 0.59 mg/cm2 or 0.6% to pig skin (in vitro), 4.14 ± 1.21% (24,658 ± 7186 ng/cm2) of the applied dose passed through the skin and 1.55 ± 0.89% (9261 ± 5330 ng/cm2) and 1.21 ± 0.56% (7189 ± 3321 ng/cm2) was found in the upper and lower skin respectively.(Wyss, 2001)

10.5 ± 3.2 µg/cm2 of Toluene-2,5-diamine sulphate when applied at a dose of 4.6 mg/cm2 as a formulation (100 mg/cm2) containing 18.4 mg (4.6%) of test material was considered as biologically available in the cutaneous absorption (in vitro) study (receptor fluid: 5.6 µg/cm2; upper dermis: 4.9 µg/cm2). (Wyss, 2004)

 [14C]-Toluene 2,5-diamine sulfate was used at a concentration of 9% (w/w) in two typical oxidative hair dye formulations:

- Formulation A containing [14C]-Toluene 2,5-diamine sulfate only

- Formulation B containing [14C]-Toluene 2,5-diamine sulfate plus a coupler (m-aminophenol) at an equimolar concentration

These two formulations were used to prepare three types of hair dye mixture:

- Mixture 1 (Formulation A/H2O): Formulation containing 9% [14C]-Toluene 2,5-diamine sulfate mixed with water at a ratio of 50/50.

- Mixture 2 (Formulation A/H2O2): Formulation containing 9% [14C]-Toluene 2,5-diamine sulfate mixed with hydrogen peroxide at a ratio of 50/50.

-Mixture 3(Formulation B/H2O2): Formulation containing 9% [14C]-Toluene 2,5-diamine sulfate and the coupler, mixed with hydrogen peroxide at a ratio of 50/50.

Formulation A : 16.11 µg/cm2 (1.87% of dose) and 32.03 µg/cm2 (3.44% of dose) of Toluene 2, 5-diamine sulfate in a hair dye formulation with H2O2 when applied to isolated human epidermis (only receptor fluid: 16.11 µg/cm2) and dermatomed human skin (malpighian epidermis: 11.77 µg/cm2, partial dermis: 1.34 µg/cm2 and receptor fluid: 18.92 µg/cm2) respectively was considered as biologically available in the cutaneous absorption (in vitro) study.

Formulation B : 37.91 µg/cm2 (4.02% of dose) and 31.26 µg/cm2 (3.41% of dose) of Toluene 2, 5-diamine sulfate in a hair dye formulation with water (without H2O2) when applied to isolated human epidermis (only receptor fluid: 37.91 µg/cm2) and dermatomed human skin (malpighian epidermis: 1.35 µg/cm2, partial dermis: 0.21 µg/cm2 and receptor fluid: 1.85 µg/cm2) respectively was considered as biologically available in the cutaneous absorption (in vitro) study. (Leclerc, 1997)

 

The total absorption of Toluene-2,5-Diamine Sulfate (in non oxidative formulations) in the in-vitro cutaneous absorption through human skin at 0.25, 0.8, 2.4 and 7.2% concentrations was 1.75 ± 0.52 (3.65%), 16.27±2.94 (9.55%), 47.23±13.35 (9.25%) and 101.03 ± 36.67 (6.43%) µg/cm2, respectively. The mean total absorption, defined as the compound-related radioactivity present in the receptor fluid, the receptor compartment wash and the skin membranes (excluding tape strips) was 1.75 μg.cm-2 (3.65 % of the applied dose, A) and 2.09 μg.cm-2 (3.49 %, E), 16.27 μg.cm-2 (9.55 %, B) and 6.92 μg.cm-2 (3.88 %, F), 47.23 μg.cm-2 (9.25 %, C) and 21.81 μg.cm-2 (3.90 %, G) and 101.03 μg.cm-2 (6.43 %, D) and 54.03 μg.cm-2 (3.49 %, H).

The mean recovery of [14C]Toluene-2,5-diamine sulphate ranged from 99.18 ± 3.21 % to 102.80 ± 5.05 % of the applied dose (Mass W J M, 1999)