t-Butyl (2S,2aS,5aR)-1-azabicyclo[3.3.0] oct-2-carboxylate monooxalate salt

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2006-09-29 to 2006-11-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study performed according to OECD guideline 423 (Acute Oral Toxicity) and ECC annex to Commission Directive 2004/73/EC, Part B, Method B.1 tris. (Acute Oral Toxicity) without deviations.

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Deviations:

no

Remarks:

The testing facility indicated that the protocol was followed without deviation.

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Deviations:

no

Remarks:

The testing facility indicated that the protocol was followed without deviation.

GLP compliance:

yes (incl. QA statement)

Remarks:

Certificate from The Department of Health of the Government of the United Kingdom

Test type:

acute toxic class method

Limit test:

no

Test material

Reference

Name:

Unnamed

Type:

Constituent

Details on test material:

- Name of test material (as cited in study report): VRT- 126028
- Molecular formula (if other than submission substance): Not applicable
- Molecular weight (if other than submission substance): Not applicable
- Smiles notation (if other than submission substance): Not applicable
- InChl (if other than submission substance): Not applicable
- Structural formula attached as image file (if other than submission substance): Not applicable
- Substance type: No data
- Physical state: White powder
- Analytical purity: 99.3 % area by GC
- Impurities (identity and concentrations): No data
- Composition of test material, percentage of components: No data
- Isomers composition: No data
- Purity test date: No data
- Lot/batch No.: 25414
- Expiration date of the lot/batch: 2008-05-01
- Stability under test conditions: No data
- Storage condition of test material: No data
- Other: No data

Test animals

Species:

rat

Strain:

other: CD (Crl:CD BR)

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Ltd., Margate, Kent, England
- Age at study initiation: 8-12 weeks of age
- Weight at study initiation: 178-221 g
- Fasting period before study: No data
- Housing: The cages were made of a stainless steel body with a stainless steel mesh lid and floor, and were suspended above absorbent paper which was changed at appropriate intervals. Cages, cage-trays, food hoppers and water bottles were changed at appropriate intervals.
- Diet: The animals were allowed free access to a standard rodent diet (Rat and Mouse No. 1 Maintenance Diet), except for overnight prior to and approximately four hours after dosing. This diet contained no added antibiotic or other chemotherapeutic or prophylactic agent.
- Water: Potable water taken from the public supply was freely available via polycarbonate bottles fitted with sipper tubes.
- Acclimation period: at least 5 days before treatment

ENVIRONMENTAL CONDITIONS
- Temperature (deg C): 19-23 deg C
- Humidity (%): 40-70%
- Air changes (per hr): The animal room was kept at positive pressure with respect to the outside by its own supply of filtered fresh air, which was passed to atmosphere and not re-circulated. Periodic checks were made on the number of air changes in the animal rooms.
- Photoperiod (hrs dark / hrs light): 12 hours light/ 12 hours dark per 24 hours

IN-LIFE DATES: From: 2006-09-29 To: 2006-11-07

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: aqueous methylcellulose

Details on oral exposure:

VEHICLE
- Concentration in vehicle: The test substance was formulated at a concentration of 30 and 200 mg/mL in the vehicle.
- Amount of vehicle (if gavage): administered at a volume of 10 mL/kg bodyweight
- Justification for choice of vehicle: No data
- Lot/batch no. (if required): No data
- Purity: No data

MAXIMUM DOSE VOLUME APPLIED
- 2000 mg/kg bw

DOSAGE PREPARATION (if unusual)
- The test substance formulations were prepared on the day of dosing. Formulations were stirred before and throughout the dosing procedure. The absorption of the test substance was not determined.

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: Two groups of three fasted female rats received a single oral gavage dose of the test substance, formulated in 1% w/v aqueous methylcellulose, at a dose level of 300 mg/kg bodyweight. As results at this dose level indicated the acute lethal oral dose of the test substance to be greater than 300 mg/kg bodyweight; in compliance with the study guidelines, a further two groups of three fasted female rats was similarly dosed at 2000 mg/kg bodyweight.

Doses:

Two groups of rats were dosed at 300 mg/kg bw. This dose level indicated the acute lethal oral dose of the test substance to be greater than 300 mg/kg body weight; in compliance with the study guidelines, a further two groups of three rats were similarly dosed at 2000 mg/kg bw.

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

- Duration of observation period following administration: All animals were observed for 14 days after dosing.
- Frequency of observations and weighing: Animals were observed soon after dosing and at frequent intervals for the remainder of day 1. On subsequent days, animals were observed once in the morning and again at the end of the experiment day (with the exception of day 15-morning only). The weight of each rat was recorded on Days 1 (prior to dosing), 8 and 15. Individual weekly body weight changes and group mean bodyweights were calculated.
- Necropsy of survivors performed: Yes
- Other examinations performed: Clinical signs, body weight, organ weights, macropathology

Statistics:

No data

Results and discussion

Preliminary study:

Not applicable

Effect levels

Sex:

female

Dose descriptor:

other: acute median lethal oral dose (LD50)

Effect level:

300 - 2 000 mg/kg bw

Mortality:

Three females dosed at 2000 mg/kg were found dead on Day 2.

Clinical signs:

Clinical signs prior to death comprised hunched posture, piloerection, salivation, unsteady gait, underactivity, and partially closed eyelids (both) seen in all three animals. In addition, reduced body temperature, post salivation staining, pallor, and drinking excessively were seen in two females. Lachrymation and irregular breathing were seen in one female. These signs were first observed from approximately ten minutes after dosing. A loss in body weight was recorded for these decedents. Macroscopic examination of the decedents treated at 2000 mg/kg revealed congestion (characterized by darkened tissues/organs or blood vessels injected) of the subcutaneous tissue, brain and heart in all three animals, and lungs, liver, spleen, stomach, duodenum, caecum, small and large intestines in two animals. Pallor of the kidneys was noted in three animals, and of the liver and spleen in one animal. Fluid contents (clear/brown or clear watery with black specks) were noted in the stomach and duodenum of three animals and the small intestine of two animals. In addition, an enlarged/ swollen/thickened heart, small (atrophy) caecum and gaseous distension of the stomach were also noted in one animal.
Clinical signs of reaction to treatment in animals which were dosed at 2000 mg/kg comprised hunched posture, piloerection, and underactivity, seen in three females. In addition, salivation and unsteady gain were noted in two females, and post-salivation staining and reduced body temperature in one female. Among animals dosed at 300 mg/kg, hunched posture, piloerection, underactivity, and aggressive behavior were seen in one female. These signs were first observed approximately 10 minutes after dosing and recovery, as judged by external appearance and behavior, by Day 2.

Body weight:

Low body weight gain was noted for three females dosed at 300 mg/kg on Day 15. All other surviving animals were considered to have achieved satisfactory bodyweight gains throughout the study.

Gross pathology:

Macroscopic examination at study termination on Day 15 revealed pallor of the lungs in two females treated at 300 mg/kg, and congestion (darkened tissue/organ) in the spleen of two animals treated at 2000 mg/kg. No abnormalities were revealed in any other animal at the macroscopic examination at this time.

Other findings:

Not applicable

Any other information on results incl. tables

Not applicable

Applicant's summary and conclusion

Conclusions:

The acute median lethal oral dose (LD 50) to rats of the test substance was demonstrated to be between 300 and 2000 mg/kg bodyweight. The study was performed to assess the acute oral toxicity of VRT-126028 (a pharmaceutical intermediate) to the rat. Two groups of three fasted female rats received a single oral gavage dose of the test substance, formulated in 1% w/v aqueous methylcellulose, at a dose level of 300 mg/kg bodyweight. As results at this dose level indicated the acute lethal oral dose of the test substance to be greater than 300 mg/kg bodyweight, in compliance with the study guidelines, a further two groups of three fasted female rats were similarly dosed at 2000 mg/kg. All surviving animals were killed as scheduled and examined macroscopically on Day 15, the end of the observation period.

Executive summary:

Not applicable