Nitroethane

Eye irritation

Administrative data

Endpoint:

eye irritation, other

Remarks:

We have only an in vivo study, no in vitro study. That is why we are using this in vivo study, in agreement with the requirements for this endpoint.

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 January 1989 - 3 February 1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was not conducted according to guidelines but was conducted according to GLPs and the report contains sufficient data for interpretation of study results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: Federal Hazardous Substances Act Regulations (16 CFR Part 1500)

Deviations:

yes

Remarks:

Since a positive response was observed in 2 of 6 rabbits, the guideline indicates the test should be repeated. The test was not repeated.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Nitroethane

EC Number:

201-188-9

EC Name:

Nitroethane

Cas Number:

79-24-3

Molecular formula:

C2H5NO2

IUPAC Name:

nitroethane

Details on test material:

Test material was described as Nitroethane - NC. No additional information available.

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

Young adult New Zealand White rabbits (Ace Animals, Inc., Boyertown, PA) were acclimated to the laboratory environment for at least five days prior to study initiation. They were observed daily during the acclimation period to assure their suitability as test animals. All housing and care conformed to the standards establisted in the "Guide for the Care and Use of Laboratory Animals" DHEW Publication No. (NIH) 85-23. Each animal was housed in a wire mesh cage and identified with an ear tag and color coded cage card. NIH 09 Rabbit Ration (Zeigler Brothers, Inc., Gardners, PA) and fresh tap water were selected randomly from the acclimated colony and assigned to the test group. The eyes of each rabbit were examined with sodium fluorescein and a slit light equipped with a cobalt blue filter prior to dosing to verify the absence of pre-existing ocular lesions.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

not specified

Amount / concentration applied:

0.1 ml was instilled into the right eye of each rabbit.

Duration of treatment / exposure:

According to the report the test material is allowed to remain on the eye till the study ends

Observation period (in vivo):

Primary eye irritation was evaluated 24, 48 and 72 hours after the test material was administered.

Number of animals or in vitro replicates:

6 rabbits

Details on study design:

Eyes were examined with sodium fluorescein and a slit light equipped with a cobalt blue filter prior to dosing to verify the absence of pre-existing ocular lesions. The test material (0.1 ml) was instilled into the right conjunctival sac of each rabbit and the lids were held together for one second and released. The animals were observed twice daily for mortality at least 5 hours apart. Primary eye irritation was evaluated 24, 48 and 72 hours after the test material was administered. The cornea, iris and conjunctiva were scored separately according to the method of Draize. The total maximum score was 110.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 24 hours

Score:

6.2

Max. score:

18

Reversibility:

not fully reversible within: 72 hours

Results 2

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 48 hours

Score:

4.2

Max. score:

9

Reversibility:

not fully reversible within: 72 hours

Results 3

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 72 hours

Score:

1

Max. score:

2

Reversibility:

not specified

Irritant / corrosive response data:

According to the report, 2 of 6 rabbits exhibited corneal irritation 24 hours after application. One of 6 rabbits exhibited iris and conjunctiva irritation 24 hrs after application. There was no evidence of corneal, iris or conjunctival irritation after 72 hours.

Other effects:

The untreated eyes of four animals exhibited diffuse areas of corneal opacity during the study.

Any other information on results incl. tables

Table 1 Summary of Primary Eye Irritation Scores

Number of	Mean Score +/- Standard Deviation after Test Article Instillation
Animals Dosed	24 hours	48 hours	72 hours
6	6.2 + 6.4	4.2 + 3.1	1.0 + 1.1
Individual Draize Values	4, 18, 2, 9, 2, 2	4, 6, 4, 9, 0, 2	2, 2, 0, 2, 0, 0

According to the classification used, the two most severe readings would equate to moderately and mildly irritating. In the case of the rabbit with a score of 18, the cornea opacity and area was rated a 1 and 1, respectively. Iris was rated a 1. Conjunctival rednes, chemosis, and discharge were 2, 1 and 1, respectively. By 48 hours, the only positive symptoms in this rabbit was conjunctival redness and chemosis which were 2 and 1, respectively. Thus the observed effects were considered to be minimal even though the rating scheme would classify the effect as moderate.

Applicant's summary and conclusion

Interpretation of results:

slightly irritating

Remarks:

Migrated information Criteria used for interpretation of results: expert judgment

Conclusions:

Based on the results of this test, nitroethane is equivocal as a primary eye irritant. The maximum average eye irritation score was 6.2 at 24 hours after dose administration. Based on this score, nitroethane is considered mildly irritating to rabbit eyes.

Executive summary:

The eye irritation potential was evaluated using the U.S. Federal Hazardous Substances Act Regulation (16 CFR Part 1500). Based on the results of this test, nitroethane is equivocal as a primary eye irritant. The maximum average eye irritation score was 6.2 at 24 hours after dose administration. Based on this score, nitroethane is considered mildly irritating to rabbit eyes.