Dibutyl phosphonate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1973

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1973

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

irritation parameters not recorded at 48 hours; test performed on both intact and abraded skin

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Dibutyl phosphonate

EC Number:

217-316-1

EC Name:

Dibutyl phosphonate

Cas Number:

1809-19-4

Molecular formula:

C8H19O3P

IUPAC Name:

dibutyl phosphonate

Test material form:

liquid

Test animals

Species:

rabbit

Strain:

New Zealand White

Test system

Type of coverage:

not specified

Preparation of test site:

other: two test sites: one was abraded and the other intact

Vehicle:

unchanged (no vehicle)

Controls:

not specified

Duration of treatment / exposure:

24 and 72 hours

Observation period:

72 hours

Number of animals:

6 rabbits

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

ca. 4

Max. score:

4

Reversibility:

fully reversible

Remarks on result:

other: Intact skin, average of 6 rabbits

Results 2

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

ca. 4

Max. score:

4

Reversibility:

fully reversible

Remarks on result:

other: Abraded skin - Average of 6 rabbits

Results 3

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

ca. 2.9

Max. score:

4

Reversibility:

fully reversible

Remarks on result:

other: Intact skin - Average from 6 rabbits

Results 4

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

ca. 2.8

Max. score:

4

Reversibility:

fully reversible

Remarks on result:

other: Abraded skin - Average of 6 rabbits

Irritant / corrosive response data:

Mean (24, 48, 72 hour) scores, with 48 hour score estimated based on the worse of either 24 or 72 hour scores, using a worst case scenario approach):
ERYTHEMA:
- Animals 1-6 (all): 4 (at all time points on all animals, on both intact and abraded skin)
OEDEMA:
- Animals 1, 2, 5, 6: 3 at 24 hours; 2 at 72 hours (both intact and abraded skin)
- Animals 3, 4: 4 at 24 hours; 2 at 72 hours (both intact and abraded skin)

Any other information on results incl. tables

Table: Results for erythema and oedema.

Erythema formation		1	2	3	4	5	6
Intact skin	24 h	4	4	4	4	4	4
	72 h	4	4	4	4	4	4
Abraded skin	24 h	4	4	4	4	4	4
	72 h	4	4	4	4	4	4
Oedema formation		1	2	3	4	5	6
Intact skin	24 h	3	3	4	4	3	3
	72 h	2	2	2	2	2	2
Abraded skin	24 h	3	3	4	4	3	3
	72 h	2	2	2	2	2	2

Applicant's summary and conclusion

Interpretation of results:

other: Category 2 (Skin irritant) based on CLP Regulation (EC) no. 1272/2008

Conclusions:

Severely irritating to rabbit skin
Erythema score: 4.0 (6 animals, at both 24 & 72 h, intact skin)
Oedema score: 3.33 at 24 hours (mean, 6 animals, intact skin) and 2.0 (6 animals, 72 h, intact skin)

Executive summary:

The skin irritation potential of the substance was evaluated in an in vivo experimental study similar to the OECD Guideline 404. The test item was applied as is to both an intact site and an abraded site of six New Zealand white rabbits, and the sites were monitored for erythema and oedema according to the Draize scale, at 24 and 72 hours after application.

All six animals demonstrated an erythema score of 4.0 at both the 24 hour and the 72 hour monitoring of both the intact and the abraded skin sites. Four out of the six animals demonstrated an oedema score of 3.0 at 24 hours on both the intact and abraded sites; the remaining two animals had a score of 4.0 at the same sites and times. At 72 hours, all six animals demonstrated an oedema score of 2.0 at both the intact and abraded sites. Reversibility of erythema and oedema was not monitored beyond 72 hours in this study. Based on these findings, the substance is considered irritating to rabbit skin.

For evaluation using the CLP regulation, it is necessary to calculate the mean erythema and oedema scores at 24, 48 and 72 hours for each animal at the intact site only. As no data for the 48 hour interval was recorded in this study, the mean was calculated using a worst-case approach, whereby the more severe of the 24 or 72 hour scores in place of the 48 hour score. The mean (24/48/72 h) erythema scores were 4.0 for all 6 animals; the mean (24/48/72 h) oedema scores were 2.67 for 4 animals, and 3.33 for 2 animals.