2,2,6,6-tetramethylpiperidin-4-ol

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study (OECD)

Data source

Reference

Reference 1

Reference Type:

other: OECD report

Title:

SIDS DOSSIER 2,2,6,6-Tetramethylpiperidin-4-ol, CAS-No: 2403-88-5

Author:

OECD SIDS

Year:

2002

Bibliographic source:

OECD SIDS

Reference 2

Reference Type:

publication

Title:

Unnamed

Year:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

GLP compliance:

yes

Remarks:

Biosafety Research Center, Food, Drugs and Pesticides (An-Pyo Center), Japan

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2,2,6,6-tetramethylpiperidin-4-ol

EC Number:

219-291-2

EC Name:

2,2,6,6-tetramethylpiperidin-4-ol

Cas Number:

2403-88-5

Molecular formula:

C9H19NO

IUPAC Name:

2,2,6,6-tetramethylpiperidin-4-ol

Details on test material:

- Name of test material (as cited in study report): 2,2,6,6-Tetramethylpiperidin-4-ol
- Analytical purity: > 99.8%
- Lot/batch No.: 6509051 (Mitsui Chemicals Inc.)

Test animals

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 10 weeks old for female and male animals
- Weight at study initiation: 359 - 400g for males; 227 - 282g for females

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

Males: for 48 days (from 2 weeks prior to mating)
Females: for 41 - 52 days (from 14 days before mating to day 3 of lactation)

Frequency of treatment:

once daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 60, 200, 600 mg/kg/day
Basis:
actual ingested

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: once a day

DETAILED CLINICAL OBSERVATIONS: Yes (see table)

BODY WEIGHT: Yes (see table)
- Time schedule for examinations: On the first day, the last day of the administration, the day of sacrifice and once a week during the administration period. For pregnant females: on the day 0, 14, and 20 of gestation and on day 0 and 4 of lactation.

FOOD CONSUMPTION: was determined on the same dy when body weight was determined for 24 hours.

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at time of necropsy
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: only males

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at time of necropsy
- Animals fasted: No data
- How many animals: only males

URINALYSIS: No
- Time schedule for collection of urine:
- Metabolism cages used for collection of urine: Yes / No / No data
- Animals fasted: Yes / No / No data
- Parameters checked in table [No.?] were examined.


NEUROBEHAVIOURAL EXAMINATION: No
- Time schedule for examinations:
- Dose groups that were examined:
- Battery of functions tested: sensory activity / grip strength / motor activity / other:

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Statistics:

Dunnett's or Scheffe's test for continuous data and Chi square test for quantal data

Results and discussion

Effect levels

Dose descriptor:

NOAEL

Effect level:

< 60 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: clinical signs: 8/12 of the male and in all female rats blepharoptosis was found

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

-Mortality and time to death: In the 600 mg/kg group, one and two males died after 6 and 9 days, respectively. Furthermore one high-dose female each died after 3 and 16 days. In the high-dose rats which died prematurely, the mortality was considered as compound-related. However, the cause of death could not be elucidated

for the dead female rat of the 60 mg/kg/day-group, since no histopathological correlate was detected.

-Body weights: For males at 200 mg/kg, a tendency for low body weight gain during administration period was observed and statistically significant difference from controls was noticed for the treatment period 29 - 43 days (Dunnets test p ≤ 0.05). Low body weight gain during the gestation period in females at 200 mg/kg was also observed (Dunnets test p ≤ 0.01).

Body weight change of male rats:

Dose level (mg/kg)	0	60	200	600
No. of animals	12	12	12	12 (N)
Days of experiment
1	385±12	385±11	385±11	385±12 (12)
8	403±17	399±23	395±13	368±41 (11)
15	422±21	419±23	409±20	402±21 (9)*
22	445±20	436±28	428±19	416±17 (9)**
29	473±20	463±29	448±19*	441±20 (9)**
36	493±21	484±32	463±23*	455±22 (9)**
43	503±18	494±29	474±24*	465±24 (9)**
49	482±19	475±32	450±26**	438±19 (9)**
Gain 1 - 43	118±14	109±22	89±20**	81±19 (9)**

Significant difference from control group; *: P ≤ 0.05 **: P ≤ 0.01; Mean ± S.D. Unit: gram

Body weight change of female rats:

Dose level (mg/kg)	0	60	200	600
Before mating period
No. of animals	12	12	12	12 (N)
Days of before mating
1	251±14	252±13	253±15	252±14 (12)
8	259±16	257±13	253±18	255±12 (11)
15	268±14	266±13	261±19	270±17 (11)
Gain 1- 15	17±8	14±9	8±8	17±14 (11)*

Dose level (mg/kg)	0	60	200	600
Gestation period
No. of animals	12	11	12	10
Day of gestation
0	281±15	276±22	274±18	280±19
7	310±16	310±18	301±22	301±22
14	350±17	349±15	339±23	336±19
21	458±20	457±22	432±30*	418±27**
Gain 0-21	176±12	181±11	158±18**	138±15**

Dose level (mg/kg)	0	60	200	600
Lactation period
No. of animals	12	11	12	10 (N)
Days of lactation
0	315±21	323±27	293±32	288±25
4	332±23	327±21	308±26	312±26 (9)
Gain 0-4	18±24	4±21	15±24	20±24 (9)

Significant difference from control group; *: P ≤ 0.05 **: P ≤ 0.01; Mean ± S.D. Unit: gram

 Food/water consumption: For males at 600 mg/kg, a tendency for increase in food consumption during administration period was observed and statistically significant differences from controls were noticed on day 8 -48 (Dunnets test p ≤ 0.01). For females at 600 mg/kg, a tendency for increase in food consumption during the premating period (Dunnets test p ≤ 0.01) and gestation period (Dunnets test p ≤ 0.05) was observed. However, the statistically significant difference from controls was not observed during the lactation period in all groups.

Food consumption change of female rats:

Dose level (mg/kg)		0	60	200	600
Before mating period
No. of animals		12	12	12	11
Days of before mating	1-8	21±1	22±1	21±2	21±1
	8-10	21±2	23±1	24±2	27±2**
Cumulative consumption	1-15	305±21	310±19	314±24	341±25**
Gestation period
No of dams		12	11	12	10
Day of gestation	0-7	27±2	28±1	28±2	29±4
	7-14	28±2	31±1	31±3	31±3*
	14-24	29±39	31±2	29±2	29±4
Cumulative consumption	0-21	539±12	626±23	614±41	627±57
Lactation period
No of dams		12	11	12	9
Day of lactation	0-4	35±10	32±8	33±8	35±10

Significant difference from control group; *: P ≤ 0.05 **: P ≤ 0.01; Mean ± S.D. Unit: gram

Food consumption change of male rats:

Dose level (mg/kg)		0	60	200	600
No of animals		12	12 (N)	12	12 (N)
Days of experiment	1-8	28±2	29±4	28±2	24±7
	8-15	30±2	31±2	31±2	35±3 (9)**
	22-29	31±2	31±2 (11)	31±2	34±3 (9)**
	29-36	32±2	32±3	32±2	35±2 (9)**
	36-43	30±2	31±2	31±2	34±2 (9)**
	43-48	30±2	31±2	30±3	34±3 (9)**
Cumulative consumption	1-15	410±28	416±36	413±30	428±36 (9)
	22-48	798±38	810±56 (11)	811±49	889±51 (9)**

Significant difference from control group; *: P ≤ 0.05 **: P ≤ 0.01; Mean ± S.D. Unit: gram

- Clinical signs: Blepharoptosis and mydriasis were observed in all groups of both sexes in a dose-related fashion. In the 60 mg/kg/day group, mydriasis was observed only in one male and one female, on the other hand blepharoptosis was observed in eight of 12 males (8/l2) and all females (12/12). Either of the clinical signs was of a slight degree and occurred only sporadically.

Clinical observation in male rats:

	Dose level (mg/kg)	Days experiment
mydriasis		1-7	8-14	15-21	22-28	29-35	36-42	43-49	Total
	0	0/12	0/12	0/12	0/12	0/12	0/12	0/12	0/12
	60	0/12	1/12	0/12	0/12	0/12	1/12	0/12	1/12
	200	4/12	4/12	0/12	0/12	0/12	8/12	2/12	9/12
	600	12/12	11/11	7/9	9/9	9/9	9/9	8/9	12/12
blepharoptosis	0	0/12	0/12	0/12	0/12	0/12	0/12	0/12	0/12
	60	3/12	2/12	1/12	1/12	0/12	6/12	0/12	8/12
	200	12/12	12/12	12/12	12/12	12/12	12/12	12/12	12/12
	600	12/12	10/11	9/9	9/9	9/9	9/9	9/9	12/12
dead	0	0	0	0	0	0	0	0	0
	60	0	0	0	0	0	0	0	0
	200	0	0	0	0	0	0	0	0
	600	1	2	0	0	0	0	0	3

Clinical observation in female rats (before and during mating period):

	Dose level (mg/kg)	Days experiment
mydriasis		1-7	8-14	15-21	22-28	29-35	36-42	43-49	Total
	0	0/12	0/12	0/12	0/0	0/0	0/0	0/0	0
	60	0/12	1/12	0/12	0/0	0/0	0/0	0/0	1
	200	3/12	1/12	0/12	0/0	0/0	0/0	0/0	4
	600	12/12	11/11	10/11	2/1	1/1	1/1	1/1	12
blepharoptosis	0	0/12	0/12	0/12	0/0	0/0	0/0	0/0	0
	60	11/12	12/12	8/12	0/0	0/0	0/0	0/0	12
	200	12/12	12/12	12/12	0/0	0/0	0/0	0/0	12
	600	12/12	11/11	11/11	2/1	1/1	1/1	1/1	12
dead	0	0	0	0	0	0	0	0	0
	60	0	0	1	0	0	0	0	1
	200	0	0	0	0	0	0	0	0
	600	1	0	0	0	0	0	0	1

Clinical observation in female rats (Gestation period):

Dose level (mg/kg)

Days experiment

Total

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

0-23

mydriasis

0

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0

60

0/11

0/11

0/11

0/11

0/11

0/11

0/11

0/11

0/11

0/11

0/11

1/11

0/11

0/11

0/11

0/11

0/11

0/11

0/11

0/11

0/11

0/11

0/11

0/11

1

200

1/12

3/12

2/12

1/12

1/12

3/12

3/12

3/12

0/12

1/12

1/12

1/12

1/12

0/12

0/12

0/12

0/12

1/12

1/12

1/12

2/12

2/12

0/12

0/12

11

600

8/10

7/10

6/10

7/10

8/10

9/10

9/10

8/10

9/10

7/10

7/10

8/10

6/10

5/10

5/10

5/10

4/10

7/10

9/10

9/10

9/10

9/10

4/10

0/10

10

blepharoptosis

0

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0/12

0

60

5/11

5/11

5/11

6/11

6/11

4/11

7/11

3/11

4/11

4/11

3/11

2/11

3/11

2/11

1/11

4/11

3/11

2/11

6/11

5/11

0/11

5/11

1/11

0/11

10

200

12/12

12/12

12/12

12/12

12/12

12/12

12/12

11/12

11/12

12/12

12/12

12/12

12/12

12/12

12/12

11/12

12/12

12/12

12/12

12/12

10/12

11/12

6/12

0/12

12

600

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

10/10

4/10

0/10

10

Clinical observation in female rats (Lactation period):

	Dose level (mg/kg)	Days experiment					Total
mydriasis		0	1	2	3	4	0-4
	0	0/12	0/12	0/12	0/12	0/12	0
	60	0/11	0/11	0/11	0/11	0/11	0
	200	10/12	10/12	8/12	2/12	0/12	12
	600	9/10	8/10	9/10	8/9	0/9	10
blepharoptosis	0	0/12	0/12	0/12	0/12	0/12	0
	60	3/11	1/11	1/11	1/11	0/11	3
	200	12/12	12/12	12/12	12/12	0/12	12
	600	10/10	10/10	9/10	9/9	0/9	10

- Haematology: Males: No dose-related changes in haematology.

- Gross pathology incidence and severity: No changes in gross pathology in the survival rats. However, the reddish spots of digestive tracts, the abnormal foci with gastric ulcer, and the vacuolar degeneration in renal tubular epithelium were observed in the discontinued rats of the 600 mg/kg group.

- Organ weight changes: Males: Increase of adrenals weight was observed in 600 mg/kg group.

Females: In 600 mg/kg, increase in adrenals and liver weights were observed.

	male			female
Dose level (mg/kg/day)	0	200	600	0	200	600
Absolute weight
Liver (g, mean ± SD)	13.56±0.08	12.94±1.92	11.76±1.09**	14.45±1.82	14.56±1.07	15.43±2.43
Adrenals (mg, mean ± SD)	66±2	67±12	71±8	80±10	862±8	87±10
Relative weight
Liver (mg, mean ± SD)	2.815±0.086	2.867±0.315	2.682±0.206	4.341±0.396	4.741±0.270	4.927±0.535**
Adrenal (mg, mean ± SD)	13.688±1.934	14.865±2.922	16.250±1.836*	24.142±2.978	26.647±2.910	27.825±2.976**

- Histopathology: No abnormalities were observed in the survival rats. However, red spots of digestive tracts, abnormal foci with gastric ulcer and vacuolar degeneration of renal tubular epithelium were observed in rats of the 600 mg/kg group which died prematurely.

Applicant's summary and conclusion

Conclusions:

Body weight gain was decreased at more than 200 mg/kg/day in both sexes. In clinical signs, blepharoptosis and mydriasis were observed in all groups of both sexes, and their changes were dose-related. In 60 mg/kg/day group, the incidence for mydriasis was low and was observed concurrently with blepharoptosis at a slight degree and only sporadically. Mortality occurred in one female at 60 mg/kg/day, and in three males and one female at 600 mg/kg/day. At 600 mg/kg/day, the discontinued rats revealed reddish spots in digestive tracts, abnormal foci with gastric ulcer and the vacuolar degeneration in renal tubular epithelium. On the basis of mortality as well as clinical signs, a NOAEL of less than 60 mg/kg/day was set under the conditions of the study.