Amides, C16-18, N-[3-(dimethylamino)propyl]

Repeated dose toxicity: dermal

Administrative data

Endpoint:

sub-chronic toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From March 14, 1984 to June 13, 1984

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: comparable to guidelines with acceptable restrictions

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Report date:

1984

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 411 (Subchronic Dermal Toxicity: 90-Day Study)

Deviations:

yes

Remarks:

Only 2 dose levels tested while guideline recommends at least 3 doses; 5 animals/sex/group against standard 10 animals/sex/group; vehicle control (30/70 EtOH/water) not tested; clinical chemistry not performed. Test material was applied only for 4 hours.

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

7651-02-7 (Stearic acid 3-(dimethylaminopropyl)amide)

IUPAC Name:

7651-02-7 (Stearic acid 3-(dimethylaminopropyl)amide)

Details on test material:

- Name of test material: Stearamidopropyldimethyl amine (SAPDMA)
-TSIN: G0250.01
- Substance type: Pure active substance
- Physical state: Waxy flake cream
- Stability under test conditions: Not reported
- Storage condition of test material: Ambient (50 - 90˚F)
- Solubility: The test material was soluble in following solvents:
5% w/w in water
5% w/w in ethanol (dispersion)
10% w/w (as melted)

Test animals

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: Not reported
- Weight at study initiation: 1970 – 2593 g
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
No information on environmental conditions is provided by the study report. However, standard operating procedure of the test facility was followed for environmental conditions.

IN-LIFE DATES: From: March 14, 1984 To: June 13, 1984

Administration / exposure

Type of coverage:

open

Vehicle:

other: 30/70 Ethanol/water

Details on exposure:

TEST SITE
- Area of exposure: Area on the back of each animals, from shoulder to rump, approximately 15 cm wide (intact skin)
- % coverage: Not reported
- Time intervals for shavings or clippings: The animals were clipped as needed while the test is in progress.

METHOD OF APPLICATIONS: Appropriate concentration of test material or control substance was applied evenly over the clipped area using a syringe.

REMOVAL OF TEST SUBSTANCE
- Washing: The treated skin was washed with tepid water and gently blotted dry with disposable paper towels or equivalent.
- Time after start of exposure: 4 hours

TEST MATERIAL:
- Amount(s) applied: 2.0 mL/kg/day (each animal received a constant dosage volume based upon its most recent bodyweight).
- Concentration: 0 (distilled water), 0.25 and 10% w/v of the test substance in 30%/70% ethanol/water.
- Constant concentration used: Yes
- Rate of preparation of dosing solution: Dosing solutions were prepared fresh weekly.
- Storage temperature of dosing solution: Stock solutions were stored at ambient temperature and humidity upon receipt and during the entire length of the study. Test solutions after preparation were stored in refrigerator. Each day’s dosing solution was equilibrated to room temperature prior to dosing.

VEHICLE: 30%/70% ethanol/water

USE OF RESTRAINERS FOR PREVENTING INGESTION: Yes, collars were used to restrain animals from oral ingestion.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

100 mL aliquot of each week’s dosing solution was sampled on the day of preparation and sent back to sponsor for analysis. A 100 mL aliquot of the distilled water control was sampled and sent for analysis on the first and last sampling. All samples were shipped under ambient conditions in glass containers.
The formulations were shown to be accurately prepared for this study. Details on analytical results are provided in the study report.

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

Once daily (5 days/week)

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 0.25 and 10 % (w/v) (equivalent to 0, 5 and 200 mg/kg bw/day) of the test substance
Basis:
nominal per unit area

No. of animals per sex per dose:

5 animals/sex/dose group

Control animals:

other: yes (distilled water)

Details on study design:

- Dose selection rationale: Not reported
- Selection of animals for experiment: Based on acclimation body weight, general health and pre-dose haematological and biochemical parameters, rabbits were selected for allocation to 3 groups. Prior to final assignment to the study, a veterinary examination was conducted to ensure that the selected rabbits were healthy.
- Rationale for animal assignment: Animals were randomized into groups by weight and sex with 5 males and 5 females in each group by weight and sex.
- Assignment of animals: The animals were assigned into following experimental groups in the study:
Group 1: Control (Distilled water (2 mL/kg))
Group 2: 0.25% w/v in 30%/70% ethanol/water (equivalent to 5 mg/kg/day)
Group 3: 10% w/v in 30%/70% ethanol/water (equivalent to 200 mg/kg/day)
All animals were dosed at a constant dosage volume of 2 mL/kg/day.

Examinations

Observations and examinations performed and frequency:

Mortality/Morbidity: Yes
- Time schedule: Once daily

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Once daily.
- Cage side observations included: Signs of ill health and abnormalities.

DETAILED CLINICAL OBSERVATIONS: Not reported

DERMAL IRRITATION: Yes, immediately prior to treatment each day (after Day 1), the skin sites were assessed on a numerical basis according to Draize skin reaction scoring system. The scoring scale for skin reactions is provided in the study report.

BODY WEIGHT: Yes
- Time schedule for examinations: All rabbits were weighed prior to dosing and subsequently at weekly intervals throughout the study.

FOOD CONSUMPTION: No

FOOD EFFICIENCY: No

WATER CONSUMPTION: No

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes, blood samples were obtained from the central ear artery and were collected into tubes containing appropriate amounts of anticoagulant (EDTA).
- Time schedule for collection of blood: 7 days prior to the start of the study and at termination.
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: All animals
- Parameters examined: Complete blood counts including a differential white blood cell count.

CLINICAL CHEMISTRY: No

Sacrifice and pathology:

SACRIFICE: Yes, all the surviving animals were sacrificed with an IV overdose of sodium pentobarbital.

GROSS PATHOLOGY: Yes, complete necropsy was performed on all animals and macroscopic appearance of the tissues was recorded.

HISTOPATHOLOGY: Yes, tissues collected at necropsy were processed for microscopic evaluations.
-Samples of the following tissues from all rabbits collected for histological examination: Lung, heart, aorta, tongue, esophagus, thyroid (parathyroid), submandibular lymph node, ileocecocolic lymph node, anterior mesenteric lymph node, stomach, liver, gallbladder, duodenum, jejunum, ileum, cecum, colon, rectum, urinary bladder, kidneys, reproductive tracts, adrenal glands, thymus, spleen, pancreas, bone marrow, skin, brain, spinal cord, sciatic nerve, submandibular salivary gland, pituitary, eye. For paired tissues (except kidney and lungs), the left side was taken for processing and the right side was placed into a save jar for possible later histology.
All tissues were fixed in 10% neutral buffered formalin with the exception of the following tissues which were fixed in a glutaraldehyde/formalin fixative:
Anterior mesenteric lymph nodes, ileocecocolic lymph node, submandibular lymph node, spleen, adrenals, duodenum, jejunum, ileum, cecum, colon, rectum.

Other examinations:

ORGAN WEIGHT: The following organs from each sacrificed animal, were dissected free of fat and weighed: Adrenals, kidneys, liver and gross observations.

Statistics:

Initial body weights, body weight changes, hematology, and organ/body weight ratios were statistically analyzed by R D Bruce and B Stinson of Statistical resources using Procter & Gamble’s computer program B8944.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Dermal irritation:

effects observed, treatment-related

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY: No mortality or test related toxicity was observed throughout the study excepting slight conjunctivitis in one animal of control and two animals of Group 2 (5 mg/kg/day) animals. This was attributed to the continuous restraint which prevented the animals from grooming themselves.
The collars of one control animal, one Group 2 (5 mg/kg/day) animal and one Group 3 (200 mg/kg/day) animal were removed temporarily because of sores on the necks. Some animals removed their collars overnight and they were collared again the next day.

BODY WEIGHT AND WEIGHT GAIN: No treatment related changes in body weight and body weight gain were observed during the study.

HAEMATOLOGY: Statistically significant increases in the WBC values were noted in the Group 3 (200 mg/kg/day) animals. In addition, there was an increase in platelet values from baseline to necropsy of the Group 2 (5 mg/kg/day) animals. The changes in WBC of the Group 3 animals were attributed to the chronic stress of collaring and not considered to be test substance related. The significant increase in platelet values of Group 2 animals were a result of low baseline values.

ORGAN WEIGHTS: No test related biologically significant changes were noted in the absolute and relative liver, kidney and adrenal weight determinations.

GROSS & HISTO PATHOLOGY (NON-NEOPLASTIC):
Treated skin on the back of rabbits in both the treated groups had a dry hair coat with an accumulation of test material on the surface at necropsy. Except the treatment site skin, no test related gross effects were observed. Histopathological examinations revealed minimal acanthosis and hyperkeratosis in the treatment sites skin of all treated groups. The incidence and severity were similar in both groups. Incidental non treatment related histopathological changes were noted in several other tissues such as brain, liver, kidney, prostate and pancreas. However, these were considered to be incidental, and not treatment related.

OTHER FINDINGS: Local Dermal Reactions:
Treatment of animals with 0.25% test material (5 mg/kg/day) in 30/70% ethanol/water produced moderate or slight erythema, slight edema, slight desquamation and slight fissuring. At 10% (200 mg/kg/day), moderate erythema, slight edema, slight desquamation and slight fissuring were produced.

Effect levels

1

Dose descriptor:

NOAEL

Remarks:

(systemic)

Effect level:

>= 200 mg/kg bw/day

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: Overall effects

2

Dose descriptor:

LOAEL

Remarks:

(local effects)

Effect level:

5 mg/kg bw/day

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: dermal irritation

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Dermal application of Stearamidopropyldimethyl amine (SAPDMA) to hair clipped skin of New Zealand White rabbits at concentrations of 0 (distilled water), 0.25 and 10% w/v of the test substance in 30%/70% ethanol/water (equivalent to 0, 5 and 200 mg/kg bw/day) for 13 weeks revealed a systemic NOAEL of ≥10% w/v (equivalent to 200 mg/kg bw/day).

Executive summary:

The subchronic toxicity study of Stearamidopropyldimethyl amine (SAPDMA) was performed following methods comparable to the OECD Guideline 411 (Subchronic Dermal Toxicity: 90-Day Study).

Male and female New Zealand White rabbits, obtained from Hazleton Research Animals were used in the study. The body weight range of animals at study initiation was 1970 – 2593 g. Animals were acclimated to laboratory conditions for a period of 7 days prior to test initiation.

Test solutions were prepared fresh weekly in distilled, 30%/70% ethanol/water for each group. Post acclimation, animals were randomized into treatment/control groups (each consisting of 5 animals/sex).

The test solution was applied to intact skin of rabbits once daily, 5 days/week for thirteen consecutive weeks at the following dose levels:

Group 1(Control): Distilled water

Group 2: 0.25% w/v in 30%/70% ethanol/water (equivalent to 5 mg/kg/day)

Group 3: 10% w/v in 30%/70% ethanol/water (equivalent to 200 mg/kg/day) 

All animals (test and control) were dosed at a constant dosage volume of 2 mL/kg/day

Appropriate concentration of test material was applied evenly on the back of each animal, from shoulder to rump (approximately 15 cm wide) using a syringe.

Animals were observed for gross toxicity daily. The skin at the treatment sites was graded prior to each day’s treatment. Body weights were taken prior to initiation and then weekly until termination. Blood was taken prior to initiation and at termination for hematological examinations. After treatment, animals were sacrificed by an IV overdose of sodium pentobarbital. Adrenals, kidneys and liver were dissected free of fat and weighed. Tissue samples (including treated skin samples) were collected for histological examinations.

No mortality or test related gross toxicity was observed throughout the study except slight conjunctivitis in one control animal and two Group 2 (5 mg/kg/day) animals. This was attributed to the continuous restraint which prevented the animals from grooming themselves. The collars of one control animal, one Group 2 (5 mg/kg/day) animal and one Group 3 (200 mg/kg/day) animal were removed temporarily because of sores on the necks. Some animals removed their collars overnight and they were collared again the next day.

Treatment of animals with 0.25% test material (5 mg/kg/day) in 30/70% ethanol/water produced moderate or slight erythema, slight edema, slight desquamation and slight fissuring. At 10% (200 mg/kg/day), moderate erythema, slight edema, slight desquamation and slight fissuring were produced. No treatment related changes in body weight and body weight gain were observed during the study. No test related biologically significant changes were noted in the absolute and relative liver, kidney and adrenal weight determinations.

Statistically significant increases in the WBC values were noted in the Group 3 (200 mg/kg/day) animals. In addition, there was an increase in platelet values from baseline to necropsy of the Group 2 (5 mg/kg/day) animals. The changes in WBC of the Group 3 animals was attributed to the chronic stress of collaring and not considered to be test substance related. The significant increase in platelet values of Group 2 animals were a result of low baseline values.

Treated skin on the backs of rabbits in both treated groups had a dry hair coat with an accumulation of test material on the surface at necropsy. Histopathological examinations revealed minimal acanthosis and hyperkeratosis at the treatment sites of all treated groups. The incidence and severity were similar in both groups. Incidental non treatment related histopathological changes were noted in several other tissues such as brain, liver, kidney, prostate and pancreas. However, these were considered to be incidental, and not treatment related.

Based on above it can be concluded that, no systemic toxicity associated with the sub chronic percutaneous exposure to test material was observed at any dose levels.

Dermal application of Stearamidopropyldimethyl amine (SAPDMA) to hair clipped skin of New Zealand White rabbits at concentrations of 0 (distilled water), 0.25 and 10% w/v of the test substance in 30%/70% ethanol/water (equivalent to 0, 5 and 200 mg/kg bw/day)for 13 weeks revealed a systemic NOAEL of ≥10% w/v (equivalent to 200 mg/kg bw/day).