1,1'-iminodipropan-2-ol

Repeated dose toxicity: dermal

Administrative data

Endpoint:

short-term repeated dose toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable well-documented publication which meets basic scientific principles.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Unnamed

Year:

2007

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 410 (Repeated Dose Dermal Toxicity: 21/28-Day Study)

Principles of method if other than guideline:

For the dermal toxicity study, 0, 100, 500 or 750 mg DIPA/kg/day was applied to an approximately 2x2 cm interscapular-dorsal area of groups of five Fischer 344 rats/sex/dose level 5 days/week for 4 weeks. Application site skin was clipped free of hair, covered with an occlusive wrap during the dosing period each day, and was reclipped as necessary during the dosing period. The wraps were removed after 6 h and the treated sites were washed by gentle padding with watersoaked gauze. Skin site of application was graded at the end of each week and the dosing period for erythema and eschar, edema, scaling and fissuring, and presence of scabs using a modification of the scoring system recommended by OECD (1981).

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1,1'-iminodipropan-2-ol

EC Number:

203-820-9

EC Name:

1,1'-iminodipropan-2-ol

Cas Number:

110-97-4

Molecular formula:

C6H15NO2

IUPAC Name:

1,1'-iminodipropan-2-ol

Details on test material:

- Name of test material (as cited in study report): Diisopropanolamine
- Analytical purity: ranged from 98.8 % - 99.6 %

Test animals

Species:

rat

Strain:

Fischer 344/DuCrj

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories Inc. (Kingston, New York and Raleigh, North Carolina)
- Diet: LabDiet #5002 Certified Rodent Diet (PMI Nutrition International, St. Louis, MO) ad libitum
- Water: tap water ad libitum



ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-25 °C
- Humidity (%): 45-60 %
- Air changes (per hr): 12-15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Type of coverage:

occlusive

Vehicle:

water

Details on exposure:

TEST SITE
- Area of exposure: 2x2 cm
- Time intervals for shavings or clipplings: at the beginning and also reclipped as necessary during the dosing period.


REMOVAL OF TEST SUBSTANCE
- Washing (if done): by gentle padding with watersoaked gauze.
- Time after start of exposure: 6 h

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

4 weeks

Frequency of treatment:

5 days/week

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 100, 500, 750 mg/kg bw/day
Basis:
nominal per unit body weight

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

WATER CONSUMPTION: Yes
- Time schedule for examinations: weekly

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at necropsy
- Anaesthetic used for blood collection: Yes with methoxyflurane or CO2
- Animals fasted: No data
- How many animals: all

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

Standard hematologic and clinical chemistry parameters were evaluated consistent with globally accepted regulatory guidelines (EEC, 1992; EPA, 1998; OECD, 1998; MITI, 1988).

URINALYSIS: Yes
- Time schedule for collection of urine: near end of study
- Metabolism cages used for collection of urine: No data
- Animals fasted: No
Standard urinalysis parameters were evaluated (EEC, 1992; EPA, 1998; OECD, 1998; MITI, 1988).

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes; Histopathologic examination was conducted on selected organs

Statistics:

Consistent with the variety of data collected, a large number of statistical methods were employed. Means and standard deviations were calculated for all continuous data. These parameters were first examined for equality of variance using Bartlett’s test (a = 0.01; Winer, 1971). If the results of the Bartlett’s test were significant, the data were transformed in an attempt to obtain equality of variances. The order of transformations used was the common log, the inverse and the square root with the best fit used for subsequent statistical testing. Weekly body weights were analyzed using a 3-way repeated ANOVA, with body weights the repeated measure and Dunnett's test for comparison to controls; terminal body weight organ weights, clinical pathology parameters and urine specific gravity were evaluated using 2-way ANOVA, separate 1-way ANOVA for each sex if sex by dose significant Dunnett's test for comparison to controls. As statistical interactions (i.e., time by dose or sex by dose) were identified in several of the tests, the alpha levels for interaction terms were set a priori at 0.01–0.10, with Bonferroni’s correction. The alpha level for comparison of individual dose groups to controls was set a priori at 0.05.

Results and discussion

Results of examinations

Details on results:

CLINICAL SIGNS AND MORTALITY
All rats survived the study period and there were no treatment-related effects.

BODY WEIGHT AND WEIGHT GAIN
no treatment related effects.

FOOD CONSUMPTION
no treatment related effects.

WATER CONSUMPTION
no treatment related effects.

HAEMATOLOGY
no treatment related effects.

CLINICAL CHEMISTRY
no treatment related effects.

URINALYSIS
no treatment related effects.

ORGAN WEIGHTS
no treatment related effects

GROSS PATHOLOGY
erythema was noted for all five males and three females treated with 750 mg/kg/day and two males and two females treated with 500 mg/kg/day. The erythema was graded as very slight (barely perceptible) for all rats except for one female treated with 500 mg/kg/day and one treated with 750 mg/kg/day in which erythema was graded as slight (well-defined) at one time during the study.

HISTOPATHOLOGY: NON-NEOPLASTIC
slight hyperkeratosis of the treated site in all rats given 750 mg/kg/day and very slight hyperkeratosis in two males and two females given 500 mg/kg/day.

Effect levels

1

Dose descriptor:

NOAEL

Remarks:

systemic toxicity

Effect level:

750 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: no systemic effects were reported

2

Dose descriptor:

NOAEL

Remarks:

local toxicity

Effect level:

100 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: dermal irritancy (100 mg/kg bw/day corresponds to 0.8 mg/cm2 assuming a body weight of 0.2 kg and as 25 cm2 skin was exposed)

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Effects of DIPA applied dermally to F344 rats for 4 weeks:

Parameter	Dose level (mg/kg/day)
	males				females
	0	100	500	750	0	100	500	750
Terminal body weight (g)	213.7	219.7	218.7	213.2	135.2	137.9	135.6	136.1
Serum urea nitrogen (mg/dL)	20	19	20	20	17	17	16	18
Kidney weight (g)	1.661	1.724	1.703	1.676	1.116	1.113	1.119	1.127
rel. kidney weight (g/100g)	0.777	0.786	0.779	0.786	0.826	0.808	0.826	0.828
Histopathology skin - treated site(no examined)	5	5	5	5	5	5	5	5
Within normal limit	5	5	3	0	5	5	3	0
Hyperkeratosis	0	0	0	5	0	0	0	5
Very slight	0	0	2	0	0	0	2	0
Slight	0	0	0	5	0	0	0	5

No statistically significant differences identified (histopathology not statistically analyzed).