N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline study (OECD TG 414)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1986

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine

EC Number:

221-375-9

EC Name:

N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine

Cas Number:

3081-14-9

Molecular formula:

C20H36N2

IUPAC Name:

N1,N4-bis(5-methylhexan-2-yl)benzene-1,4-diamine

Details on test material:

Santoflex 77, purity: 100%

Test animals

Species:

rat

Strain:

other: Charles River CD rats

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Analytical verification of doses or concentrations:

yes

Details on mating procedure:

M/F ratio per cage: 1:1

Duration of treatment / exposure:

days 6 to 15 of gestation

Frequency of treatment:

daily

Duration of test:

study termination on gestation day 20

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 25, 75, 150 mg/kg bw/day
Basis:

No. of animals per sex per dose:

25 per group

Control animals:

yes, concurrent vehicle

Results and discussion

Results: maternal animals

Effect levels (maternal animals)

1

Dose descriptor:

NOAEL

Effect level:

150 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

2

Dose descriptor:

NOAEL

Effect level:

25 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

3

Dose descriptor:

LOAEL

Effect level:

75 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

MATERAL TOXICITY

Mortality

control: 0/25

25 mg/kg/day: 0/25

75 mg/kg bw/day: 1/25

150 mg/kg/day: 4/25

Four 150 mg/kg/day females died between gestation days 16 and 17 and one 75 mg/kg/day female died on gestation day 17. All control and 25 mg/kg/day females survived to scheduled sacrifice.

Clinical signs

The 150 mg/kg/day females that died prior to sacrifice generally exhibited red matter (presumably blood) around and/or expelled from the vaginal opening; red matter under the cage; stained, wet and/or matted haircoat; and ptyalism. Of the aforementioned clinical signs, ptyalism was the only observation also noted in the 75 mg/kg/day female that died. The necropsy observations of the animals that died were not meaningfully different from those of the control animals. Of the animals that survived to scheduled sacrifice, stained, wet

and/or matted haircoat (primarily located in the anogenical region) was noted at increased incidence at the 150 mg/kg/day dosage level and ptyalism was apparent at all tested dosage levels although the incidencewas very low.

Gross lesions

Treatment-related gross internal lesions were not noted at necropsy.

Body Weights

Body weight loss was observed during the initial subinterval of treatment (gestation days 6—9) at the 150 mg/kg/day dose level.

Moreover, body weight gains during both the overall treatment and gestation intervals (gestation days 6-15 and 0-20, respectively) were reduced, relative to the control, at the 75 and 150 mg/kg/day dosage levels.Treatment-induced differences in body weight gain were not evident at the 25 mg/kg/day dose level.

(GD 0 to 20):

 Group mean Body weight change

	Group mean maternal body weight change (grams)
Day of gestation	Control	25 mg/kg/d	75 mg/kg/d	150 mg/kg/d
0 to 6	29 ± 7.4	26 ± 6.0	25 ± 5.4	24 ± 10.7
6 to 9	3 ± 5.7	6 ± 5.0	3 ± 6.2	-4 ± 6.5
9 to 12	11 ± 4.8	11 ± 5.9	9 ± 8.1	14 ± 7.4
12 to 16	18  ± 6.7	21 ± 6.2	14 ± 8.1	5 ± 17.3
16 to 20	58 ± 7.2	58 ± 8.6	56 ± 16.6	58 ± 11.9
6 to 15	32 ± 10.1	38 ± 7.2	26 ± 13.5	16 ± 18.3
0 to 20	119 ± 16.2	122 ± 14.9	108 ± 15.6	105 ± 20.4

Group mean body weight

	Group mean maternal body weights (grams)
Day of gestation	Control	25 mg/kg/d	75 mg/kg/d	150 mg/kg/d
0	275 ± 21.7	272 ± 22.2	265 ± 23.5	263 ± 26.9
6	305 ± 26.1	299 ± 24.5	290 ± 26.2	287 ± 29.5
9	307 ± 28.9	304 ± 25.4	293 ± 27.1	283 ± 28.5
12	318  ± 29.9	316 ± 24.2	302 ± 25.9	297 ± 29.6
16	337 ± 32.0	336  ± 28.2	316 ± 28.0	304 ± 31.1
20	394  ± 33.9	394 ± 31.5	373  ± 36.0	366 ± 40.2

Cesarean Section Observations

No differences attributable to treatment were observed in the dams or fetuses at Cesarean section.

The mean fetal body weight value at 25 mg/kg/day was significantly higher than the control and was attributed to inherent biological

variation for lack of similar findings at the 75 and 150 mg/kg/day dose levels.

Table: Summary of maternal and fetal observation at Cesaren Section

	Control	25 mg/kg/d	75 mg/kg/d	150 mg/kg/d
Animal on study	25	25	25	25
Animals that were gravid	23	23	20	22
Animals that died	0	0	1	4
Animals that diet nongravid	0	0	0	0
Animals that diet gravid	0	0	1	4
Animals examined at Cesarean section:	25	25	24	21
Nongravid:	2	2	5	3
Gravid	23	23	19	18
Dams with viable fetuses	23	23	19	18
Viable fetuses/dam	13.7  ± 2.36	13.7  ± 1.5	13.4 ±  3.13	13.1 ± 2.63
Postimplantation loss/dam:	1.2 ± 1.19	1.2 ± 1.03	1.5 ± 1.74	1.3 ± 1.67
Total Implantations/dam	14.9  ± 2.09	14.8 ± 1.56	14.9 ±  3.31	14.4± 2.20
Corpora lutea/dam	16.4  ± 2.17	16.0 ± 1.99	15.8 ± 2.49	15.9 ± 2.19
Group mean preimplantation loss (%)	9.0	7.6	5.3	9.4
Group mean postimplantation loss (%)	7.9	7.9	10.2	8.9
Mean fetal body weight (g)	3.3  ± 0.29	3.5*± 0.44	3.3 ± 0.26	3.3 ± 0.21
Fetal sex distribution - male (%)	152 (48.1)	160 (51.0)	126 (49.4)	117 (49.6)
Fetal sex distribution- female (%)	164 (51.9)	154 (49.0)	129 (50.6)	119 (50.4)

* significant different from control (p<0.05)

FETAL MORPHOLOGICAL OBSERVATIONS

Malformations

Malformations that were observed in the treated groups occurred in low incidence and were not considered treatment related. One high-dose fetus had anophthalmia, one mid-dose and two control fetuses had microphthalmia and another mid-dose fetus had ectopia cordis and scernoschisis.

Table summary of the Incidence of fetal malformation

dosage levels	control	25 mg/kg/d	75 mg/kg/d	150 mg/kg/d
No. of litters examined	23	23	19	18
No. of fetuses examined externally	315	314	255	236
No. of fetuses examined viscerally	157	157	128	118
No. of fetuses examined skeletally	159	157	127	118
Malformations observed	No. of  fetuses (no. of litters)
Anophthalmia				1 (1)
Microphthalmia	2 (2)		1 (1)
Ectopia cordis			1 (1)
Sternoschisis			1 (1)
total fetuses (litters) with malformations	2 (2)	0 (0)	2 (2)	1 (1)

Developmental Variations

No meaningful differences were noted between the incidence of developmental variations seen in the treated groups and those in the

control.

Table: summary of the incidence of fetal devlopmental variations

Dosage levels	control	25 mg/kg/d	75 mg/kg/d	150 mg/kg/d
No. of litters examined	23	23	19	18
No. of fetuses examined externally	315	314	255	236
No. of fetuses examined viscerally	157	157	128	118
No. of fetuses examined skeletally	159	157	127	118
Developmental Variations observed	No. of fetuses (No. of litters)
retroesophageal right subclavian			1 (1)
Renal papilla not developed and/or distended ureters		1 (1)		4 (3)
Skull reduced in ossification	4 (1)	2 (2)	4 (3)
hyoid unossified	2 (2)	4 (4)	10 (6)	1 (1)
27 presacral vertebrae	1 (1)	1 (1)
25 presacral vertebrae		1 (1)	5 (3)	1 (1)
Vertebrae reduced in ossification	1 (1)
7th cervical rib(s)	3 (3)	3 (3)	1 (1)	8 (4)
Greater than 13 full pairs of ribs	1 (1)
14th rudimentary rib(s)	4 (4)		3 (3)	1 (1)
Fewer than 13 full pairs of ribs	10 (5)	7 (3)	17 (4)	13 (6)
entire sternum unossified	1 (1)
Sternebrae #5 and/or #6 unossified	65 (20)	46 (17)	50 (16)	51 (16)
other sternebra unossified	1 (1)		3 (3)
misalligned sternebra	1 (1)			2 (2)
Ischium(a)reduced in ossification	1 (1)		1 (1)
total fetuses (litters) with variations	77 (22)	57 (20)	68 (17)	64 (17)

TEST ARTICLE ANALYSES

Stability

Means of 6 hour stability assay values were within + 10% of target concentrations. These results indicated that the test

material/vehicle preparations were stable and suitable for study initiation.

Concentration

Test suspensions contained average concentrations ranging from 92% to 95% (October 7, 1985) and 102% to 108% (October 18, 1985) of target levels.