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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
December 1976
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to primary skin irritation test design in effect since 1976, but not according to OECD Guideline.

Data source

Referenceopen allclose all

Reference Type:
other: CIR study summary
Title:
Unnamed
Year:
1976
Report date:
1976
Reference Type:
review article or handbook
Title:
Final Report of the Cosmetic Ingredient Review expert Panel: Amended Safety Assessment of Methylparaben, Ethylparaben, Propylparaben, isopropylparaben, and Benzylparaben
Author:
Bergfeld, W. F. et. al.
Year:
2006
Bibliographic source:
Cosmetic Ingredient review, Washington, US, 1-86, 2006

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Primary skin irritation test design in effect since 1976.
The method is a modification of the Draize technique and is similar to that used in grading skin irritation in the Human Patch Test. The highest grade at either the 2 or 24 hour reading is used to calculate the Primary Irritation Index (PII).
GLP compliance:
no
Remarks:
study performed before GLP guidelines

Test material

Constituent 1
Chemical structure
Reference substance name:
Methyl 4-hydroxybenzoate
EC Number:
202-785-7
EC Name:
Methyl 4-hydroxybenzoate
Cas Number:
99-76-3
Molecular formula:
C8H8O3
IUPAC Name:
methyl 4-hydroxybenzoate
Constituent 2
Reference substance name:
Methylparaben
IUPAC Name:
Methylparaben
Details on test material:
- Name of test material (as cited in study report): Methylparaben 0410
- Product type: per se
- Concentration: 100%
- Concentration tested: 100%

Test animals

Species:
rabbit
Strain:
other: Albino
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Specie: Albino rabbit
- Sex: female
- Age at study initiation: no data
- Weight at study initiation: no data
- Housing: no data
- Diet (e.g. ad libitum): no data

ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data
- Humidity (%): no data
- Photoperiod (hrs dark / hrs light): no data

Test system

Type of coverage:
occlusive
Preparation of test site:
shaved
Vehicle:
unchanged (no vehicle)
Controls:
yes
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 ml
- Frequency: once
- Product type: per se
- Concentration tested: 100%

VEHICLE: none
Duration of treatment / exposure:
24 hrs
Then the occlusive dressing was removed.
Observation period:
24 and 72 hrs after contact
Number of animals:
9
Details on study design:
METHODS:
Nine healthy female albino rabbits were used to study each material.
The test material was applied to a 1" filter disc which was held in contact with the clipped skin of the back of the animal by Blenderm tape. The trunk of each animal was then wrapped with an occlusive plastic sheet and secured with Elastoplast tape.

OBSERVATIONS:
The occlusive dressing was removed after 24 hours of contact, and the skin sites graded for irritation and edema after 24 and 72 hours according to the scoring system based on a maximum of

PSI Scores:
0 = no evidence of any effect
1/2 = (Barely Perceptible) = minimal faint uniform or spotty erythema
1 = (Mild) = pink uniform erythema covering most of contact site
2 = (Moderate) = Pink-red erythema visibly uniform in entire contact area
3 = (Marked) = Bright red erythema with accompaning edema, petachiae or papules
4 = (Severe) = Deep red erythema with vesiculation or weeping with or withourt edema

PSI = Primary Skin Irritation Score, Maximum Score = 4.0
PII = Primary Irritation Index - a value depicting the average skin response of the test panel as a whole. It is calculated by adding the Irritation Scores and dividing by the total number of test subjects.

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
primary dermal irritation index (PDII)
Basis:
mean
Time point:
24/48/72 h
Score:
0.67
Max. score:
4
Reversibility:
no data
Remarks on result:
other: test item; readings performed after 24 and 72 h
Irritation parameter:
primary dermal irritation index (PDII)
Basis:
mean
Time point:
24/48/72 h
Score:
0.44
Max. score:
4
Reversibility:
no data
Remarks on result:
other: control; readings performed after 24 and 72 h
Irritation parameter:
erythema score
Basis:
animal #1
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: n.a.
Remarks on result:
other: no evidence of any effect; readings performed after 24 and 72 h
Irritation parameter:
erythema score
Basis:
animal: 2-7
Time point:
24/48/72 h
Score:
0.5
Max. score:
4
Reversibility:
not specified
Remarks on result:
other: minimal faint uniform or spotty erythema; readings performed after 24 and 72 h
Irritation parameter:
erythema score
Basis:
animal: 8
Time point:
24/48/72 h
Score:
1
Max. score:
4
Reversibility:
not specified
Remarks on result:
other: pink uniform erythema covering most of contact site
Irritation parameter:
erythema score
Basis:
animal: 9
Time point:
24/48/72 h
Score:
2
Max. score:
4
Reversibility:
not specified
Remarks on result:
other: pink-red erythema visibly uniform in entire contact area
Irritation parameter:
edema score
Basis:
mean
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
other: n.a.
Remarks on result:
other: readings performed after 24 and 72 h

Any other information on results incl. tables

 SCORE  0  1/2  1  2  3  4
 Number of Animals Test  1  6  1  1  0  0
  Control  4  2  3  0  0  0

Applicant's summary and conclusion

Interpretation of results:
not irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test material, when evaluated for primary skin irritation by a 24-hour patch test conducted on intact skin, was found to be not irritating.
Executive summary:

The test material, when evaluated for primary skin irritation by a 24-hour patch test conducted on intact skin, was found to be not irritating to skin.