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

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2006-12-18 to 2007-04-11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study performed according to OECD Guideline 405 (Acute Eye Irritatoin/Corrosion) and EU Method B.5 (Acute Toxicity: Eye Irritation/Corrosion) 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 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Remarks:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Deviations:

no

Remarks:

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

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

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

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): C14H23NO6
- Substance type: pure active substance
- Physical state: solid, white powder
- Analytical purity: 99.3% area by GC
- Purity test date: 2006-05-22
- Lot/batch No.: lot# WYJ11410404533/batch# 0000025414
- Expiration date of the lot/batch: 2008-05-01
- Storage condition of test material: room temperature

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Highgate Farm, Market Rasen, Lincolnshire, England
- Age at study initiation: approximately 31 to 36 weeks
- Weight at study initiation: 3.37 - 4.73 kg
- Housing: housed individually in plastic cages with perforated floors
- Diet (e.g. ad libitum): 125 g of a standard laboratory rabbit diet (Rabbit GD Diet Pellets supplied by Highgate Farm) per day; A dietary supplement of hay was offered during acclimatisation until two days prior to dose instillation, for the remainder of acclimatisation and throughout the study observation period whole-meal bread was offered.
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least nine weeks


ENVIRONMENTAL CONDITIONS
- Temperature (deg C): 16 to 20 deg C
- Humidity (%): 40 to 70%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12 hours dark/ 12 hours artificial light per 24 hour period


IN-LIFE DATES: From: no data To: no data

Test system

Vehicle:

unchanged (no vehicle)

Controls:

other: left eye remained untreated and served as control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 mL of the test substance weighing approximately 64 mg
- Concentration (if solution): no data


VEHICLE
- Amount(s) applied (volume or weight with unit): not applicable
- Concentration (if solution): not applicable
- Lot/batch no. (if required): not applicable
- Purity: not applicable

Duration of treatment / exposure:

single ocular dose

Observation period (in vivo):

8 days

Number of animals or in vitro replicates:

three

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): no data
- Time after start of exposure: no data


SCORING SYSTEM:
OCULAR RESPONSES:
- The untreated eye was used as a comparison with the treated eye during assessment of ocular lesions. Ocular irritation was assessed using a numerical system (scoring ranged from 0-4, with 0 being no reaction) which included the following observations: Cornea Opacity (No opacity, Scattered or diffuse areas of opacity (other than slight dulling of normal lustre), details of iris clearly visible- Easily discernible translucent areas- details of iris slightly obscured, Nacreous areas- no details of iris visible- size of pupil barely discernible, Opaque cornea- iris not discernible through the opacity) and Area of cornea involved (None, One quarter (or less) but not zero, Greater than one quarter but less than half, Greater than half but less than three quarters, Greater than three quarters up to whole area); The presence or absence of corneal ulceration or stippling was designated + (positive) or – (negative) using a numerical system (scoring ranged from 0-2, with 0 being no reaction) which included the following observations: Iris (Normal, Markedly deepened rugae- congestion- swelling- moderate circumcorneal hyperaemia or injection- any of these or combination of any thereof, iris still reacting to light (sluggish reaction is positive), No reaction to light- haemorrhage- gross destruction (any or all of these), Conjunctiva Redness (Blood vessels normal, Some blood vessels definitely hyperaemic (injected), Diffuse crimson colour individual vessels not easily discernible, Diffuse beefy red)), and Chemosis (No swelling, Any swelling above normal (includes nictating membranes), Obvious swelling with partial eversion of lids, Swelling with lids about half-closed, Swelling with lids more than half-closed). The presence or absence of ulceration or necrosis was designated + (positive) or – (negative) assessed using a numerical system (scoring ranged from 0-4, with 0 being no reaction) which included the following observations: Discharge (No discharge, Any amount different from normal, Discharge with moistening of lids and hairs adjacent to lids, Discharge with moistening of lids and hairs of a considerable area around eye, Extensive mucoid discharge ).
SCORING SYSTEM:
- Corneal scoring using the grade for degree of opacity density (A) and the grade for the area of cornea
involved (B): Corneal score = A x B x 5 (theoretical maximum = 80), Iridial scoring using the grades for iritis (C): Iridial score = C x 5 (theoretical maximum = 10), Conjunctival score using the grade for conjunctival redness (D), chemosis grade (E) and grade for discharge (F): Conjunctival score = (D + E + F) x2 (theoretical maximum = 20). The scores for each area are meaned for each time point and the highest total meaned score is used for the classification thus:
Total Mean Score Classification
0.0 – 0.5 Non-irritating
0.5 – 2.5 Practically non-irritating
2.5 – 15 Minimally irritating
15 – 25 Mildly irritating
25 – 50 Moderately irritating
50 – 80 Severely irritating
80 – 100 Extremely irritating
100 – 110 Maximally irritating


TOOL USED TO ASSESS SCORE:
- An ophthalmoscope and a pencil beam torch were used to facilitate inspection of the eyes. From the 24 hour examination onwards, fluorescein was used, if necessary to aid the examination of the cornea.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

maximum mean total score (MMTS)

Basis:

mean

Time point:

other: 1 hour

Score:

13

Max. score:

110

Remarks on result:

other: Area of the eye: cornea, iritis, conjunctiva

Results 2

Irritation parameter:

maximum mean total score (MMTS)

Basis:

mean

Time point:

other: 24 hours

Score:

9.3

Max. score:

110

Remarks on result:

other: Area of the eye: cornea, iritis, conjunctiva

Results 3

Irritation parameter:

maximum mean total score (MMTS)

Basis:

mean

Time point:

other: 48 hours

Score:

5.7

Max. score:

110

Remarks on result:

other: Area of eye: cornea, iritis, conjunctiva

Results 4

Irritation parameter:

maximum mean total score (MMTS)

Basis:

mean

Time point:

other: 72 hours

Score:

1.3

Max. score:

110

Remarks on result:

other: Area of eye: cornea, iritis, conjunctiva

Results 5

Irritation parameter:

maximum mean total score (MMTS)

Basis:

mean

Time point:

other: 8 days

Score:

0

Max. score:

110

Reversibility:

fully reversible within: 8 days

Remarks on result:

other: Area of eye: cornea, iritis, conjunctiva

Irritant / corrosive response data:

Injection of the conjunctival blood vessels or a crimson-red conjunctival appearance was evident during the first seventy-two hours after instillation. Very slight or slight chemosis and slight or moderate discharge were evident during the first forty-eight hours. Diffuse or scattered areas of opacity covering up to a quarter of the corneal surface were apparent in one animal one hour after instillation and in a further animal twenty-four and forty-eight hours after instillation. The treated eye of each animal was overtly normal eight days after instillation. Instillation of the test substance gave rise to a slight or moderate initial pain response.

Other effects:

There was no sign of toxicity or ill health in any rabbit during the observation period.

Any other information on results incl. tables

EC R36 trigger values (classification triggered if any value attained by two or more animals): >= 2, <3 for corneal opacity; >= 1, <2 for iridial lesions; >= 2.5 for conjunctival redness; and >=2 for conjunctival chemosis.

EC R41 trigger values (classification triggered if any value attained by two or more animals): >= 3 for corneal opacity, and 2 for iridial lesions.

Applicant's summary and conclusion

Conclusions:

Instillation of the test substance gave rise to a “minimally irritating” response and the test substance did not require labelling with the risk phrase R36, “Irritating to eyes”, in accordance with Commission Directive 2001/59/EC.

Executive summary:

Not applicable