4-methyl-m-phenylenediamine

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Comparable to OECD 417 guideline study (GLP)

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Reference 2

Reference Type:

publication

Title:

Route-dependent comparative metabolism of [14C]toluene 2,4-diisocyanate and [14C]toluene 2,4-diamine in Fischer 344 rats

Author:

Timchalk C, Smith FA & Bartels MJ

Year:

1994

Bibliographic source:

Toxicol.Appl.Pharmacol. 124: 181-90

Materials and methods

Objective of study:

excretion

metabolism

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 417 (Toxicokinetics)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

4-methyl-m-phenylenediamine

EC Number:

202-453-1

EC Name:

4-methyl-m-phenylenediamine

Cas Number:

95-80-7

Molecular formula:

C7H10N2

IUPAC Name:

4-methylbenzene-1,3-diamine

Details on test material:

Unlabelled TDA:
- Name of test material (as cited in study report): 2,4-toluene-diamine (2,4-TDA)
- Analytical purity: >99%
- Lot: AX13004AX
- Supplier: Aldrich Chemical Company (Milwaukee, USA)

Radiolabelled TDA:
- Lot No.: 030H9222
- Supplier: Sigma Chemical Company (St Louis, USA)
- Radiochemical purity (if radiolabelling): 97.7%
- Specific activity (if radiolabelling): 20.7 mCi/mmol
- Locations of the label (if radiolabelling): uniformly ring labelled

Radiolabelling:

yes

Remarks:

14C-labeled

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratory, Kingston, NY, USA
- Weight at study initiation: approximately 200 g
- Individual metabolism cages: yes
- Diet: Rodent Chow ad libitum
- Water: tap water ad libitum
- Acclimation period: one week

ENVIRONMENTAL CONDITIONS
- Photoperiod (hrs dark / hrs light): 12 h/ 12 h

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The radiotracer was diluted with non-radiolabeled compound to obtain a target radioactivity of 67 µCi/g of dosing solution. Adequate non-radiolabeled 2,4-TDA was added to the 3 and 60 mg/kg dose solutions to obtain target concentrations of 1 and 20 mg 2,4-TDA/g dosing solution, respectively. The final administration volume was 3ml dosing solution/kg bw.
The dosing solutions were analyzed for radioactivity and 2,4-TDA. The amount of radioactivity in the TDA dose solutions ranged from 83% to 148% of target, and all solutions were within 10% of their target concentration.

Duration and frequency of treatment / exposure:

Single exposure

Doses / concentrations

Remarks:

Doses / Concentrations:
3 or 60 mg/kg bw

No. of animals per sex per dose / concentration:

4

Control animals:

no

Details on study design:

Two groups of four male rats each were administered single oral doses of 3 or 60 mg 14C-2,4-TDA/kg of bw. Following oral administration of 14C-2,4-TDA, four rats/group were placed in glass Roth-type metabolism cages, and urine and feces were collected for up to 48 hr and analyzed for radioactivity. At 48 hr post-dosing the rats were sacrificed and selected tissues were collected and analyzed. Pooled urine specimens were analyzed by GC/MS and GC/MS/MS.

Details on dosing and sampling:

- Body fluids sampled: urine, feces, cage washes
- Time and frequency of sampling: Urine 12 h intervals, feces 24 h intervals, expired air 24 h
- From how many animals: samples pooled from 4 animals
- Method types for identification:
Liquid Scintillation Counting: determination of overall radioactivity
HPLC-Analysis: separation of urinary metabolites and quantification of 2,4-TDA
GC/MS and GC/MS/MS analysis: analysis of free 2,4-TDA, acid-labile conjugates of 2,4-TDA and mono and diacetyl TDA.

Results and discussion

Toxicokinetic / pharmacokinetic studies

Details on absorption:

93-97% of the administered radioactivity was recovered in urine, feces, tissues, carcass and final cage wash.
Given that the majority of compound is excreted by urine it can be assumed that 14C-TDA is well orally absorbed.

Details on distribution in tissues:

No data

Details on excretion:

The urine was the primary excretion route accounting for ca. 64 % of the administered radioactivity, while 22 - 31 % was recovered in the feces. For all treatment groups the percent radioactivity recovered in the carcass/skin was comparable, accounting for 2 - 5% of the administered dose, and less than 0.5% was recovered in the final cage wash. Comparison of the oral 60 and 3 mg 14 C-2,4-TDA/kg body weight treatment groups indicated no quantitative dose dependent differences in the routes of elimination (table 1).
Half-lives derived from urinary excretion time course:
t1/2 (60mg/kg) = 8h
t1/2 (3mg/kg) = 4.6h

Metabolite characterisation studies

Metabolites identified:

yes

Details on metabolites:

Monoacetyl 2,4-TDA, Diacetyl 2,4-TDA, free 2,4-TDA and acid-labile conjugates were detected in urine (see table 2).
The amounts of acetylated metabolites and 2,4-TDA detected in the urine from all treatment groups were proportional to the administered dose. Comparison of the ratio between the free + acetylated TDA metabolites with the total acid-labile metabolites indicated that following an oral dose of 60 mg/kg 14C-2,4-TDA approximately 61% of detected metabolites existed as either free or acetylated 2,4-TDA while the remaining 39% existed as other conjugates of 2,4-TDA. Whereas, following the 3 mg/kg dose, between 84% and 87% of the detectable metabolites were identified as either acetylated or free 2,4-TDA. This indicates that at lower doses, 2,4-TDA does not undergo much conjugation other than acetylation.

Any other information on results incl. tables

Table 1: Distribution of radioactivity 48 h after male Fischer 344 rats were given oral doses of 3 or 60 mg 14C-2,4-TDA/kg bw.

	Percentage of administered 14C-2,4-TDA
	3 mg/kg bw dose group	60 mg/kg bw dose group
Urine	63.67 ± 15.0	64.96 ± 2.47
Feces	30.7 ± 3.78	22.57 ± 1.54
Skin&Caracass	2.02 ± 0.36	4.62 ± 1.67
Cage wash	0.24 ± 0.11	0.49 ± 0.12
Recovery	96.62 ± 12.08	92.63 ± 0.67

Table 2: Concentration of 2,4 -TDA metabolites expressed as 2,4-TDA equivalents in the 0-12 h urine specimen following oral exposure to 14C-2,4 -TDA; Values are given as µg equivalents 2,4-TDA/ g urine

	3 mg/kg bw dose group	60 mg/kg bw dose group
Monoacetyl 2,4-TDA	1.13	24.36
Diacetyl 2,4-TDA	1.88	20.34
Free 2,4-TDA	0.73	18.03
free + acetylated  2,4-TDA	3.74	62.73
2,4-TDA acid-labile conjugate	4.47	102.41

Table 3: Concentration of 2,4 -TDA metabolites expressed as 2,4 -TDA equivalents in the 0 -12 h urine specimen following oral exposure to 14C-2,4 -TDA; Values are given as absoluteµg equivalents 2,4-TDA.

	3 mg/kg bw dose group	60 mg/kg bw dose group
Monoacetyl 2,4-TDA	6.09	247.9
Diacetyl 2,4-TDA	10.13	206
Free 2,4-TDA	3.93	183.48
free + acetylated 2,4-TDA	20.15	638.37
2,4-TDA acid-labile conjugate	24.09	1042.18
free+acetylated/acid labile	88%	62%