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Toxicological information

Specific investigations: other studies

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Administrative data

Endpoint:
specific investigations: other studies
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
publication
Title:
Depigmentation from 4-Tertiary Butyl Catechol - An Experimental Study
Author:
Gellin GA, Possick PA, Perone VB
Year:
1970
Bibliographic source:
J Investigative Dermatology, 55(3), 190-197

Materials and methods

Principles of method if other than guideline:
Depigmentation
GLP compliance:
no
Type of method:
in vivo
Endpoint addressed:
not applicable

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Viscous 4-tert-butylpyrocatechol (4-TBC), 100%, was supplied by the American Oil Company, Chicago, Illinois.
Pure cristalline 4-TBC was supplied by Dow Chemical Company, Midland, Michigan.
No other data available

Test animals

Species:
guinea pig
Strain:
other: Unspecified (randomly bred, English, short-haired, black Guinea pigs)
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Mr Robert Kydd, 71 Elm St., Chelmsford, Mass.
- Age at study initiation: adult
- Weight at study initiation: 675 grams
- Fasting period before study: no
- Housing: individual cage
- Diet: ad libitum, supplemented twice weekly with fresh lettuce
- Water: no data
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
no data

Administration / exposure

Route of administration:
dermal
Vehicle:
other: acetone, DMSO, assembly oil blend or propylene glycol
Details on exposure:
TEST SITE
- Area of exposure: 9 cm² (3 cm x 3 cm)
- % coverage: no data
- Time intervals for shavings or clipplings: no data

TEST MATERIAL
- Amount(s) applied: 0.1 mL
All concentrations of 4-TBC used were weighed in volume solutions, except for viscous 4-TBC, diluted in solvents as volume in volume solutions.
The materials tested were:
- pure crystalline 4-TBC in acetone, DSMO, propylene glycol or assembly oil blend
- viscous 4-TBC in acetone or assembly oil blend

Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
3 weeks
Frequency of treatment:
daily application
Post exposure period:
3 months
No. of animals per sex per dose:
12 animals for all study
Details on study design:
The dorsal skin of unepilated ears was painted daily for three weeks with a glass rod. At least one shaved area was left untreated.
Punch biopsies were performed on treated and control sites.

Concentrations: see Table 1 in part "Results and discussions"

Examinations

Examinations:
The depigmentation observed was classified as follows: absent - no visible depigmentation; definite, but weak - small spots or speckles of hypopigmentation; definite, but moderate - uniform hypopigmenting; very strong - complete depigmentation.

Results and discussion

Details on results:
Depigmentation was induced only when the solvent carriers contained 4-TBC in suitable concentrations. Pigment loss was confined to the skin of test sites when pure crystalline 4-TBC was incorporated into acetone, DMSO, or assembly oil blend, but not in propylene glycol.
When viscous 4-TBC was dissolved in acetone depigmentation was also induced. However, when incorporated into the assembly oil blend, uniform hyperpigmentation was induced at all concentrations.
No pigmentary change developed without antecedent inflammation.

Any other information on results incl. tables

Table 1: Evaluation of depigmenting potency and irritant effects of 4-TBC in different vehicles at various concentrations in twelve black guinea pigs

 

Solvent

Concentration grams %

Degree of irritation

Depigmenting potency

4-TBC, crystalline

Acetone

0.005

0

absent

 

 

0.05

0

absent

 

 

0.1

0

absent

 

 

0.5

+

absent

 

 

1

++

absent

 

 

5

++++

definite, but weak*

 

 

10

++++

definite, but weak*

 

DMSO

1

+

definite, but moderate

 

 

5

++++

definite, but moderate

 

 

10

++++

strong

 

Propylene glycol

1

0

absent

 

 

5

++

absent

 

 

10

+++

absent

 

Assembly oil blend

5

++++

strong

 

 

10

++++

strong

 

 

 

 

 

4-TBC, viscous

Acetone

0.005

0

absent

 

 

0.05

0

absent

 

 

0.1

+

absent

 

 

0.5

+

absent

 

 

1

++++

strong

 

 

5

++++

strong

 

 

10

++++

strong

 

Assembly oil blend

0.005

++++

absent#

 

 

0.05

++++

absent#

 

 

0.1

++++

absent#

 

 

0.5

++++

absent#

 

 

1

++++

absent#

* Hyperpigmentation of the skin followed the inflammatory reaction, but some hairs depigmented.

# Hyperpigmentation of the skin and hairs followed the inflammatory reaction.

Applicant's summary and conclusion

Conclusions:
These findings confirm the ability of 4-tert-butylpyrocatechol (4-TBC) to depigment black guinea pig skin when incorporated into a variety of solvents.
Uniform hyperpigmentation was seen when 4-TBC was incorporated into the assembly oil blend at all concentrations.