Registration Dossier

Administrative data

Endpoint:
short-term repeated dose toxicity: oral
Remarks:
combined repeated dose and reproduction / developmental screening
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study performed according to accepted guideline

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report Date:
2006

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
Qualifier:
according to
Guideline:
other: OPPTS 870.3650
GLP compliance:
yes
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
CAS 593-51-1 (methylamine hydrochloride), Alfa Aesar, 99.46% stated, 99.2% (calculated using titration with silver nitrate and 2,7-dichlorofluorescein as an indicator), stored at room temperature

Test animals

Species:
rat
Strain:
other: Wistar (Crl:CD®(SD)IGS BR)
Sex:
male/female
Details on test animals and environmental conditions:
Source: Charles River Laboratories, Inc., Raleigh, NC
Age at study initiation: 65 days
Weight at study initiation: 296.5 - 356.2 g (males) and 200.4 - 250.1 g (females)

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Duration of treatment / exposure:
Males: 118-119 days/Females: 98-112 days
Frequency of treatment:
Daily
Doses / concentrations
Remarks:
Doses / Concentrations:
0 (Vehicle), 250, 500, and 1000 mg/kg/day
Basis:

No. of animals per sex per dose:
12 per sex per dose group (96 total)
Control animals:
yes, concurrent vehicle
Details on study design:
ADMINISTRATION:
- Test duration: 118-119 days (males), 98-112 days (females)
- Dosing Schedule: all animals were dosed daily except during delivery (females)
- Route of administration: gavage
- Doses: 0 (Vehicle), 250, 500, and 1000 mg/kg/day
- Dose volume: 4 mL/kg bw
- Vehicle: Nanopure water

MATING PROCEDURES:
- Ten weeks after the beginning of treatment, males and females from the same dose group were co-housed for no longer than 14 days in a ratio of 1:1
- The day of detection of sperm in the vaginal smear was designated day 0 of gestation
- Females were allowed to litter and rear their pups until day 4 after parturition

Examinations

Observations and examinations performed and frequency:
EXAMINTAIONS:
- Mortality: twice daily on all animals
- Clinical observations: once a day on all animals, detailed observations once a week on all animals
- Food consumption and body weight: determined once per week with the following exceptions: not during mating for males or females and on day 0, 7, 14, and 20 post coitum for females and on days 0 and 4 postpartum for females with litter. Pups were weighed on days 1 and 4 postpartum

Hematology and clinical chemistry:
Blood samples:
- For hematology, clinical chemistry: from orbital sinus of fasted F0 animals under CO2 anesthesia on day 69/70
- For coagulation parameters: from the abdominal vena cava of all F0 animals at sacrifice under CO2 anesthesia (day 118-119 for males and day 98-112 for females)
- Hematology: red blood cell count, hemoglobin, hematocrit, mean corpuscular (cell) volume, mean corpuscular (cell) hemoglobin, mean corpuscular (cell) hemoglobin concentration, red cell distribution width, prothrombin time, activated partial thromboplastin time, absolute reticulocyte count, platelet count, white blood cell count, differential white blood cell count, microscopic blood smear examination
- Clinical chemistry: alanine aminotransferase, aspartate aminotrasferase, sorbitol dehydrogenase, alkaline phosphatase, total bilirubin, urea nitrogen, creatinine, triglycerides, cholesterol, glucose, total protein, albumin, globulin, inorganic phosphate, calcium, sodium, potassium, chloride
- Urinalysis: on day 69 (males) and 70 (females): quality, color, clarity, volume, osmolality, pH, glucose, ketone, urobilinogen, bilirubin, blood, protein, microscopic urine sediment examination
Sacrifice and pathology:
Microscopic:
- For 5 animals/sex/dose in the control and high dose group: liver, duodenum, jejunum, ileum, cecum, colon, rectum, kidneys, urinary bladder, spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow (femur), thyroid gland, adrenal glands, brain (including cerebrum, cerebellum, medulla pons), spinal cord (including cervical, mid-thoracic and lumbar), sciatic nerve, femur
- For all animals: trachea, lungs, stomach
- For all male animals: heart
- Any organs which had gross pathological lesions at necropsy in any dose group
- Reproductive organs from all animals in the control and high dose groups: testes, epididymides, prostate, seminal vesicles, coagulation glands, ovaries, oviducts, uterus, cervix, vagina
-The presence and number of uterine implantation sites and ovarian corpora lutea were evaluated for all cohabited females
- Testes and epididymides of animals that were killed as scheduled were fixed in modified Davidson's solution

- Organs examined at necropsy (F0 animals only): organ weight: liver, kidneys, adrenal glands, thymus, spleen, brain, heart, testes, epididymides
- Organs examined at necropsy (F1 pups): none, gross examination only, including those pups that did not survive to sacrifice
Other examinations:
NEUROBEHAVIORAL:
- Functional observational battery and motor activity measurement: an abbreviated functional observational battery (forelimb and hindlimb grip strength, open field observations and motor activity) was conducted on all animals prior to initiation of test substance administration (day 2 (males) and day 1(females)) and prior to the end of the premating period (day 62 (males) and day 63 (females))
- Body weights were collected on the day of neurobehavioral assessments
Statistics:
Primarily, Levene's test for homogeneity, one-way analysis of variance, Dunnett's test, Kruskal-Wallis test, Dunn's test and Cochran-Armitage test for trend

Results and discussion

Results of examinations

Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Details on results:
MORTALITY:
- No specific treatment-related deaths at any dose

FUNCTIONAL OBSERVATIONAL BATTERY AND MOTOR ACTIVITY ASSESSMENT:
- No adverse effects/findings at any dose

F1 pups: CLINICAL EXAMINATIONS (DAYS 0-4 POSTPARTUM):
- No adverse effects/findings at any dose

TOXIC EFFECTS BY DOSE LEVEL:
1000 mg/kg bw/day:
F0 parental animals:
CLINICAL EXAMINATIONS/CLINICAL PATHOLOGY/URINALYSIS/PATHOLOGY:
- Slight (not significant) reductions in body weight, body weight gain, and food consumption in male F0 animals from the first week to the end of the study
- Statistically significant reductions in body weight gain in female F0 animals during the first week of gestation
- Statistically significant reductions in food consumption in female F0 animals on days 0-14 premating and during the first week of gestation
- Statistically significant increases in absolute and relative liver and relative kidney weights in both sexes without correlative changes in enzyme levels or gross or microscopic changes
- Statistically significant increases in relative kidney weights in both sexes without correlative gross or microscopic changes
- Minimal to mild squamous metaplasia of the tracheal mucosa and minimal focal mucous metaplasia of the gastric glandular mucosa of several rats of both sexes, probably the result of topical exposure to the test substance
- Statistically significant decrease in hemoglobin concentration on day 70 in females, associated with minimal, but statistically significant, increases in red blood cell distribution width, reticulocytes counts and several microscopic changes, treatment-related
- Statistically significant decrease in eosinophils on day 69 in males, treatment-related, but without associated changes in other white blood cell parameters and not considered adverse
- Statistically significant increase in cholesterol on day 70 in females, treatment-related
- Statistically significant decrease in glucose on day 69 in males, minimal, but treatment-related
- Statistically significant decrease in globulins, and consequently total protein, on day 69 in males, treatment-related
- Statistically significant decrease in globulins, on day 70 in females, minimal, but treatment-related
- Statistically significant increase in urine osmolality on day 69 in males, treatment-related
- Decrease (statistical significance not reported) in urine ketones on day 69 in males, dose-related
- Statistically significant decrease in urine pH on day 69/70 in males and females, treatment-related, probably adaptive
- Renal epithelial cells were present on day 70 in 4/11 females without correlative histological changes in the kidney

500 mg/kg bw/day:
F0 parental animals
CLINICAL EXAMINATIONS/CLINICAL
PATHOLOGY/URINALYSIS/PATHOLOGY
- Statistically significant increase in absolute (females) and relative liver weights in males and females without correlative changes in enzyme levels or gross or microscopic changes
- Statistically significant decrease in glucose on day 69 in males, minimal, but treatment-related
- Statistically significant decrease in globulins, and consequently total protein, on day 69 in males, treatment-related
- Statistically significant increase in triglycerides on day 70 in females, not treatment-related
- Statistically significant decrease in urine pH on day 69/70 in males and females, treatment-related, probably adaptive
- Decrease (statistical significance not reported) in urine ketones on day 69 in males, dose-related
- Statistically significant increase in urine volume on day 69 in males and females, not dose-related
- Statistically significant decrease in urine protein (urine micrototal protein) on day 70 in females, not dose-related

250mg/kg bw/day:
F0 parental animals
CLINICAL EXAMINATIONS/CLINICAL PATHOLOGY/URINALYSIS/PATHOLOGY:
- Statistically significant increase in relative liver weights in males without correlative changes in enzyme levels or gross or microscopic changes
- Statistically significant decrease in globulins on days 69/70 in males, minimal, but treatment-related
- Statistically significant increase in alkaline phosphatase activity on day 69 in males, not treatment-related
- Statistically significant decrease in urine pH on day 70 in females, treatment-related, probably adaptive
- Decrease (statistical significance not reported) in urine ketones on day 69 in males, dose-related -renal epithelial cells were present on day 70 in 1/12 females without correlative histological changes in the kidney, treatment-related

Effect levels

Dose descriptor:
NOAEL
Effect level:
500 other: mg/kg bw/day

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

Mean Absolute and Relative (% body weight) Liver and Kidney Weights

.

Male

Female

Dose (mg/kg/d)

0

250

500

1000

0

250

500

1000

Final Body Weight (g)

608

623

618

589

356

351

353

343

Liver Weight (g)

18.71

21.30

21.51

21.90*

13.09

13.63

15.49*

14.51*

Liver % Body Weight

3.08

3.41*

3.47*

3.72*

3.67

3.90

4.39*

4.23*

Kidney Weight (g)

4.13

4.36

4.25

4.35

2.49

2.58

2.59

2.63

Kidney % Body Weight

0.68

0.70

0.69

0.74*

0.70

0.74

0.73

0.77*

*Statistically significant (alpha = 0.05) by Dunnett/Tamhane-Dunnett pair-wise test (parametric)

Applicant's summary and conclusion

Conclusions:
- Slight (not significant) reductions in body weight as compared with controls and body weight gain in male F0 animals from the first week to the end of the study at 1000 mg/kg bw
- Statistically significant reductions in body weight as compared with controls, body weight gain and food consumption in female F0 animals during gestation and days 0-14 at 1000 mg/kg bw
- Many minimal, but statistically significant, changes in blood, urine and clinical chemistry in both sexes at 1000 mg/kg bw
- The NOAEL for general, systemic toxicity of the test substance is 500 mg/kg body weight/day for the F0 parental rats