7,7-dimethyl-3-oxa-6-azaoctan-1-ol

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 1984

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted in accordance with generally accepted scientific principles, possibly with incomplete reporting or methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1985

Report date:

1985

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Deviations:

not specified

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

7,7-dimethyl-3-oxa-6-azaoctan-1-ol

EC Number:

400-390-6

EC Name:

7,7-dimethyl-3-oxa-6-azaoctan-1-ol

Cas Number:

87787-67-5

Molecular formula:

Hill formula: C8 H19 N O2 CAS formula: C8 H19 N O2

IUPAC Name:

2-[2-(tert-butylamino)ethoxy]ethan-1-ol

Details on test material:

- Name of test material (as cited in study report):
MRD-82-178

- Physical state:
Amber liquid

- Analytical purity:
Assumed to be 100% pure

Batch No:
3

- Storage condition of test material:
Room temperature under nitrogen

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:
Charles River Breeding Labs Inc., Lakeview Facility, NJ

- Age at study initiation:
Approximately 10 to 11 weeks

- Weight at study initiation:
Males: 354 - 410 g; Females: 217 - 259 g

- Housing:
Individual during the study (group housed 5/sex/cage during acclimation)

- Diet (e.g. ad libitum):
Purina Certified Rodent Chow (mash) ad libitum

- Water (e.g. ad libitum):
Automatic watering system ad libitum

- Acclimation period:
34 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C):
Monitored twice daily; maintained range of 68 to 76 degrees Fahrenheit

- Humidity (%):
Monitored twice daily; maintained range to 40 to 70% relative humidity

- Photoperiod (hrs dark / hrs light):
Approximately 12 hourd light and 12 hours dark by automatic timer.

IN-LIFE DATES: From: Day 1 To: Day 30

Administration / exposure

Route of administration:

other: Oral: syringe and a No. 16 stainless steel ball-tipped feeding needle

Vehicle:

water

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
The test material was diluted to a 25% (w/v) solution in vehicle by the Compound Preparation Department. Dose levels were generated based on the results of a Rangefinding Study conducted from August 13th 1984 to September 28th 1984 (not recorded). Fresh dosing solutions were prepared daily during the first week of dosing and weekly thereafter until study termination.

Analytical verification of doses or concentrations:

no

Details on analytical verification of doses or concentrations:

Not applicable

Duration of treatment / exposure:

30 Days

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
10 mg/kg
Basis:
actual ingested

Doses / concentrations 2

Remarks:

Doses / Concentrations:
30 mg/kg
Basis:
actual ingested

Doses / concentrations 3

Remarks:

Doses / Concentrations:
60 mg/kg
Basis:
actual ingested

No. of animals per sex per dose:

10 Male, 10 Female per dose

Control animals:

yes, concurrent no treatment

Details on study design:

- Dose selection rationale:
Dose levels were generated based on the results of a Rangefinding Study conducted from August 13th 1984 to September 28th 1984 (not recorded)

Positive control:

Not applicable

Examinations

Observations and examinations performed and frequency:

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule:
Clinical observations were made daily for the nature, onset and duration of the toxicological signs throughout the study.

BODY WEIGHT: Yes
- Time schedule for examinations:
Recorded during the week prior to dosing (pretest), at dosing initiation (Day 0), and weekly thereafter, on Monday. Body weights were also recorded at the scheduled sacrifice and at death for animals which succumbed prior to study termination.


HAEMATOLOGY: Yes
- Time schedule for collection of blood:
Blood samples were collected from the abdominal aorta after an overnigh fast (food was removed at approximately 1600 hours on the previous day) on the day of scheduled sacrifice.
- Anaesthetic used for blood collection: No data
- Animals fasted: Yes
- How many animals: All survivors
- Parameters checked are as follows:
erythrocyte count
haematocrit
haemoglobin
leukocyte count (total and differential (d))
mean corpuscular volume
mean corpuscular haemoglobin
mean corpuscular haemoglobin conentration
platelet count
reticulocyte count (a)


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood:
Blood samples were collected from the abdominal aorta after an overnigh fast (food was removed at approximately 1600 hours on the previous day) on the day of scheduled sacrifice.
- Animals fasted: Yes
- How many animals: All survivors
- Parameters checked are as follows:
albumin
blood urea nitrogen
calcium
cholesterol
creatinine
electrolytes (Na+, K+, Cl-)
gamma glutamyl transpeptidase
glucose
inorganic phosphorus
serum glutamic pryuvic transaminase (c)
total bilrubin
total protein
triglyceride

Sacrifice and pathology:

TERMINATION
After a minimum of 30 days of oral administration of MRD-82-178 all surviving animals were weighed, anesthetized by methoxyfluorane and sacrificed by exsanguination.

NECROPSY:
The necropsy included a physical examination of the external surface, all orifices, the carcass, the cranial cavity, the thoracic, abdominal and pelvic cavities with their associated organs and tissues, and the tissues and organs of the neck.
The following organs were weighed prior to fixation for all animals sacrificed at termination:
adrenals
kidneys
liver
testes

The following tissues and organs were taken and preserved in 10% neutral buffered formalin for all animals:
all gross lesions
liver
kidneys
testes
stomach
jejunum
caecum
rectum
heart
spleen
adrenals
esophagus
duodenum
ileum
colon

Preserved tissues from control and high dose groups were processed, sectioned, stained (hematoxylin and eosin) and mounted on glass slides for histopathological examination to be arranged by the sponsor. Tissues from the low and mid dose groups were processed to the paraffin block stage only.

Other examinations:

Not applicable.

Statistics:

The following parameters were statistically analysed for significant differences:
mean quantitative haematology
mean serum chemistry parameters
mean organ weights
mean organ relative organ weights
mean body weights, by weighing period
mean food consumption

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

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:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Details on results:

CLINICAL SIGNS AND MORTALITY
A survival bar graph is presented in Table 2 (attached). Nine animals either died or were euthanised prior to study termination; 1 male and 2 females from Group IV, 3 females from Group III, 2 females from Group II and 1 female from Group I. Two of these animals were confirmed as dosing accidents at necropsy.

The incidence of in-life observations is presented in Table 1 (attached). Individual in-life observations are presented in Appendix G (attached).

There was an overall low incidence of clinical in-life observations noted in all groups; however, wet and dry rales were noted at a higher incidence for the treated group animals. Red nasal discharge, dry red nasal discharge, alopecia, truncated tail, red ocular discharge, ataxia, oral discharge, dyspnea, staining of the ano-genital area, urinary staining, hypothermia, small amount of stool, clear ocular discharge, fecal staining, eye partially closed and hypoactivity were also noted in treated and/or control animals with no apparent pattern.

BODY WEIGHT AND WEIGHT GAIN
Individual animal weights by time, sex and dose are presented in Appendix H and the mean values with statistics are presented in Table 3.

There was an increase in mean body weight for all groups over the course of the study. The treated male groups gained weight at the same rate as the controls while the female treated groups gained at a slower rate than the controls. The female Group III mean body weight was significantly different from the controls on Day 7 only.

HAEMATOLOGY
Individual quantitive haematology parameters are presented in Appendix L and the mean haematology parameters with statistics are presented in Table 7. The individual qualitative haematology parameters are presented in Appendix M.

There was slight difference among the haemaglobin means for the groups of males, but this difference was not statistically nor biologically significant. There were no other statistically significant differences between treated and control mean haemotology values.

CLINICAL CHEMISTRY
The individual serum chemistry values are presented in Appendix N and the mean serum chemistry values with statistics is presented in Table 8.

There was a statistical difference among the male group means for inorganic phosphorus, but this difference showed a lack of fit to linear response and was not statistically nor biologically significant. There were no other statistically significant differences noted between the treated and control group mean serum chemistry values.

ORGAN WEIGHTS
Mean organ weights by dose and sex are presented un Table 5 and the mean relative organ weight values are presented in Table 6. Individual animal organ weights are presented in Appendix J with the relative organ weights listed in Appendix K.

There were no significant differences between treated and control male mean organ or relative organ weights nor were there any significant differences between female treated and control mean organ weights. The Group III and IV female mean relative adrenal weights were, however, increased when compared to the control value. This response exhibited a linear relationship to dose, and was statistically significant for Group IV only.

GROSS PATHOLOGY
Individual necropsy observations are presented in Table 9.

The most frequently noted observations at gross necropsy examination were discoloration of the stomach mucosa and dilated renal pelves. Stomach discoloration was noted in 1 control animal and 4 Group IV animals, while dilated renal pelves were not the same control animal, 2 Group II animals and 3 Group IV animals. Abnormalities of gastro-intestinal tract (esophagus, stomach, ileum and jejunum) were also noted more frequently than other observations, notably in the treated groups animals which died prior to study termination.

Effect levels

Dose descriptor:

NOAEL

Effect level:

60 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: overall effects clinical signs; mortality; body weight; haematology and clinical chemistry.

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

The objective of this study was to evaluate the effects of MRD-82 -178 when administered by the oral route, via gavage, daily, for a minimum of 30 days.
The NOAEL was found to be 60 mg/kg/day.

Executive summary:

The objective of this study was to evaluate the effects of MRD-82 -178 when administered by the oral route, via gavage, daily, for a minimum of 30 days. Eighty Sprangue-Dawley rats were divided in 4 groups of 10 males and 10 females each. Dose levels were generated based on the results of the Rangefinding Study conducted prior to study initiation. Group I was used as a control which received vehicle only. Groups II, III and IV received doses of 10, 30 and 60 mg/kg of MRD-82 -178, respectively.

Observations were made as to the nature, onset, severity and duration of toxicological signs daily for the duration of the study. Body weights were recorded prior to dosing, at dosing initiationm and weekly thereafter during the test period. Body weights were also recorded at death for animals which succumbed prior to study termination. Food consumpotion was measured weekly. Serum chemistry and haemotology studies were performed on all surviving animals at termination.

After at least 30 days of oral administration of MRD-82 -178, all surviving animals were weighed, anesthetised by methoxyfluorane, and blood samples collected from the abdominal aorta; animals were killed by exsanguination. Necropsies were performed and required organs and tissues were collected and weighed.

Nine animals died prior to study termination; two of these animals were confirmed at necropsy as dosing accidents.

There was an overall low incidence of clinical in-life observations noted in the treated and control groups. However, rales and emaciation were noted at a slightly higher incidence for treated group animals than for control group animals.

There were no significant differences noted between male control and treated mean animal weights or mean food consumption during the study. The female treated group animals appeared to gain weight at a lower rate than the controls. The Group III female body weights on Day 7 were significantly less than the control group. The mean food consumption values for the treated females were also less than the control values. This decrease was statistically significant for the Week 1 food consumption interval.

There was no statistically nor biologically significant differences in mean haemotology or serum chemistry values between the treated and control groups. There were no significant differences in male organ weight or relative organ weight mean values between the treated and control groups. The mean femal organ weight values showed no differences between the treated and control groups. However, the Group II and IV female mean relatice adrenal weights were increased when compared to the control value. This response was linearly related to dose, and was statistically significant for Group IV only.

Gross postmortem examination revealed a slightly higher incidence of discolouration of the stomach mucosa and dilate renal pelvis in the high dose animals when compared to controls. Gastro-intestinal tract abnormalities were also limited to animals in the treated groups.