L-(+)-2,5-diaminopentanoic acid

Endpoint summary

Description of key information

Based on the results of the study, a no-observed-adverse effect level (NOAEL) of 3445 and 3986 mg/kg body weight/day was established for male and female rats.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1993-09-22 to 1994-06-22 and 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Japanese guidelines for Toxicity Studies Required for Applications for Approval to Manufacture (Import) Drugs (MHW, 1989), and with the Revision of Guidelines for Single-Dose and Repeated-Dose Toxicity Studies (MHW, 1993).

GLP compliance:

yes

Limit test:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Kyowa Hakko Bio Co., Ltd. Batches 080926 and 083019
- Expiration date of the lot/batch: practically stable
- Purity test date: 1993-08-27


STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: stable
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: highly soluble
-
TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: none

Purity >/= 99.9 %

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

Seventy-five male and 75 female Crj:CD (SD) strain specific pathogen free rats (4 weeks of age) were purchased from Charles River Japan, Inc. and allowed to acclimate for 2 weeks. Animals were maintained at 22 °C, with a relative humidity of 55%, and food and water were provided ad libitum. At 6 weeks of age, 60 healthy males and 60 healthy females were selected for the study.

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

Rats (12/sex/group) were administered L-ornithine monohydrochloride in the diet at concentrations of 0 (basal diet control), 1.25%, 2.5%, or 5.0% for 13 weeks. An additional 6 animals/sex/group were administered the basal diet or 5.0% L-ornithine monohydrochloride for 13 weeks, followed by the basal diet control for an additional 5 weeks (recovery period). The highest dose was selected based on an estimated 200-fold factor from the maximum anticipated exposure in humans.

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

134 weeks; 90 d as to repeated dose oral toxicity

Frequency of treatment:

Treatment: by food ad libitum

Dose / conc.:

12 500 mg/kg diet

Remarks:

Equivalent to 1.25 % in the diet

Dose / conc.:

25 000 mg/kg diet

Remarks:

Equivalent to 2.5 % in the diet

Dose / conc.:

50 000 mg/kg diet

Remarks:

Equivalent to 5 % in the diet

No. of animals per sex per dose:

12
An additional 6 animals/sex/group were administered the basal diet or 5.0% L-ornithine monohydrochloride for 13 weeks, followed by the basal diet control for an additional 5 weeks (recovery period).

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: Low toxicity expected.
- Rationale for selecting satellite groups: random
- Post-exposure recovery period in satellite groups: 5 weeks

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: weekly (indicated in the related study report B-2523-1)
- Cage side observations checked in table were included. (in the related study report B-2523-1)

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: twice daily during treatment period, once daily during recovery period

BODY WEIGHT: Yes
- Time schedule for examinations: weekly, both treatment period and recovery period

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Yes


OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: prior to administration, week 13 of treatment period, week 5 of recovery period
- Dose groups that were examined: all

HAEMATOLOGY: Yes
- Time schedule for collection of blood: last day of treatment period
- Anaesthetic used for blood collection: Not specified
- Animals fasted: Yes
- How many animals: all
- Parameters checked in table were examined. (in the related study report B-2523-1)

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: last day of treatment period, end of recovery period
- Animals fasted: Yes
- Parameters checked in table were examined. (in the related study report B-2523-1)

URINALYSIS: Yes
- Time schedule for collection of urine: and 13 of the treatment
period, and on week 5 of the recovery period.
- Metabolism cages used for collection of urine: Not specified
- Animals fasted: Yes
- Parameters checked in table were examined. (in the related study report B-2523-1)

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: twice daily during the treatment period, and once daily during the recovery period
- Dose groups that were examined: all
- Battery of functions tested: sensory activity / grip strength / motor activity / other: abnormal behaviour

IMMUNOLOGY: No

OTHER:

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (Table see the related study report B-2523-1)

HISTOPATHOLOGY: Yes Yes (Table see the related study report B-2523-1)

Statistics:

Quantitative data were analyzed for homogeneity of variance by the Bartlett method. Data with homogeneous variance were subjected to an analysis of variance (ANOVA) with a Dunnett or Scheffe post hoc test. Data with heterogeneous variance were analyzed by the Kruskal–Wallis rank test with a Dunnett or Scheffe
post hoc test. Statistical significance was designated at p < 0.05 or 0.01.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

Transient differences in body weight were observed during the recovery period in rats originally receiving 5.0% L-ornithine monohydrochloride compared to controls; however, these differences were not observed during the treatment period and only occurred in one sex, and were thus deemed to be incidental.

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

Transient differences in body weight and food consumption were observed during the recovery period in rats originally receiving 5.0% L-ornithine monohydrochloride compared to controls; however, these differences were not observed during the treatment period and only occurred in one sex, and were thus deemed to be incidental.

Food efficiency:

effects observed, non-treatment-related

Description (incidence and severity):

Males receiving 5.0% L-ornithine monohydrochloride exhibited a transient decrease in food efficiency in week 1 of the treatment period compared to controls; however, this was not sustained and was not observed in females or in other dose groups. Therefore, this decrease was determined to be of no toxicological significance. Males receiving 5.0% L-ornithine monohydrochloride also exhibited a transient, statistically significant increase in food efficiency in week 2 of the recovery period. However, this was not observed in the treatment period or in females receiving the same dose, and therefore was deemed to be incidental.

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

effects observed, non-treatment-related

Description (incidence and severity):

Not a drinking water study but non-treatment related effects examined and recorded.

A significant increase in water intake was observed in males receiving 5.0% L-ornithine monohydrochloride in week 1 of the treatment period compared to controls. A tendency toward high values of water intake also was noted in these males; however, no statistically significant increase in water intake was observed in females receiving 5.0% L-ornithine monohydrochloride. No clear differences in water intake were observed during the treatment period.

Ophthalmological findings:

no effects observed

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

A significant increase in the percentage of reticulocytes were observed in males receiving 5.0% L-ornithine monohydrochloride at the end of the treatment
period compared to controls; however, values remained within historical control ranges, it was not observed following the recovery period, and was not observed in females. Therefore, this observation was deemed to be incidental. At the end of the recovery period, a significant increase in the percentage of lymphocytes and a decrease in segmented neutrophils were observed in males receiving 5.0% L-ornithine monohydrochloride, and a significant decrease in the percentage of lymphocytes and a significant increase in segmented neutrophils were observed in females in the same dose group. As these changes were in opposite directions for the genders, they were deemed to be incidental in nature.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

A significant decrease in serum chloride was observed in males receiving 2.5% and 5.0% L-ornithine monohydrochloride at the end of the treatment period compared to controls. Additionally, a significant increase in alkaline phosphatase activity was observed in females receiving 2.5% L-ornithine monohydrochloride compared to controls; however, this was not observed in females receiving 5.0% L-ornithine monohydrochloride and was thus deemed to be incidental. At the end of the recovery period, a significant decrease in the percentage of a2-globulin was observed in males in the 5.0% L-ornithine monohydrochloride group; however, this was not observed during the treatment period and was not observed in females. Therefore, this observation was deemed to be incidental.

Urinalysis findings:

effects observed, non-treatment-related

Description (incidence and severity):

In weeks 5 and 13 of the treatment period, a significant increase in urinary chloride was observed in males and females receiving 2.5% and 5.0% L-ornithine monohydrochloride compared to controls. At week 5 of the recovery period, a significant decrease in potassium and chloride excretion was observed in females receiving 5.0% L-ornithine monohydrochloride compared to controls. As the change in potassium excretion was not observed during the treatment period, this was deemed to be an incidental finding. The decrease in chloride excretion observed in females was in the opposite direction of that observed during the treatment period; therefore, the change was deemed to be of no toxicological significance. No other changes in urinalysis parameters were observed during the treatment or recovery periods.

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Description (incidence and severity):

At necropsy in week 13, a significant increase in the relative (to body) kidney weight was observed in males receiving 5.0% L-ornithine monohydrochloride compared to controls; however, this was unilateral, was not observed in females, and no significant differences were observed in absolute kidney weight. Therefore, this was deemed to be an incidental observation. At necropsy conducted following the 5-week recovery period, a significant increase in the absolute and relative kidney weight was observed in males receiving 5.0% L-ornithine monohydrochloride. Again, this was only observed unilaterally and was not observed in females. As such, this was concluded also to be an incidental observation.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

Incidental findings, only.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Histopathological changes observed at the end of the treatment period were noted in the stomach, liver, pancreas, pituitary, thyroid gland, spleen, cervical lymph node, kidney, eyeball, and thoracic wall; however, these were considered to be incidental based on the incidence of their occurrences and their pathological nature

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Key result

Dose descriptor:

NOAEL

Effect level:

3 445 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: All results

Key result

Dose descriptor:

NOAEL

Effect level:

3 986 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: all results

Key result

Critical effects observed:

no

Conclusions:

Based on the results of the study, a no-observed-adverse effect level (NOAEL) of 3445 and 3986 mg/kg body weight/day was established for male and female rats.

Executive summary:

L-Ornithine monohydrochloride was evaluated in a rat 90-day oral toxicity study.

Rats were administered L-ornithine monohydrochloride at dietary concentrations of 0 (basal diet), 1.25%, 2.5%, or 5.0% for 90 days. No changes in body weight, food consumption, ophthalmoscopy, or hematology were observed. Transient increases in water intake and urinary volume, and a decrease in specific gravity were observed in males receiving 5.0% L-ornithine monohydrochloride; however, these were likely attributable to the central role of ornithine in the urea cycle and the consequent increase in urea production. A decrease in serum chloride concentration and an increase in urinary chloride excretion were observed; however, these were likely attributable to administration of the hydrochloride salt of ornithine and were not considered to be of any toxicological significance. No remarkable findings were noted at necropsy.

Based on the results of the study, a no-observed-adverse effect level (NOAEL) of 3445 and 3986 mg/kg body weight/day was established for male and female rats.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

3 445 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

Klimisch 1

System:

other: Entire organism

Organ:

other: Entire organism

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
Regarding inhalation, the combination of low volatility, a negative Log Kow and high water solubility suggests that absorption directly across the respiratory tract epithelium is unlikely.

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
Regarding inhalation, the combination of low volatility, a negative Log Kow and high water solubility suggests that absorption directly across the respiratory tract epithelium is unlikely.

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: dermal

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
[Specific explanation in addition to field 'Justification for data waiving']

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: dermal

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
[Specific explanation in addition to field 'Justification for data waiving']

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the results of the study, a no-observed-adverse effect level (NOAEL) of 3445 and 3986 mg/kg body weight/day was established for male and female rats.

The substance is practically non-toxic and does not meet the criteria for classification as to CLP.