o-phenylenediamine

Dermal absorption

Administrative data

Endpoint:

dermal absorption in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

Insufficient information to adequately evaluate data. Did not include recovery data or exposure duration; Focus was on correlating percutaneous absorption to partition coefficients

Data source

Reference

Reference Type:

publication

Title:

Percutaneous absorption of hair dyes: correlation with partition coefficients

Author:

Bronaugh RL, Congdon ER

Year:

1984

Bibliographic source:

J Invest Dermatol, 83:124-127

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 428 (Skin Absorption: In Vitro Method)

Deviations:

yes

Remarks:

No information on exposure time, preparation of test material or recovery data

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

o-phenylenediamine

EC Number:

202-430-6

EC Name:

o-phenylenediamine

Cas Number:

95-54-5

Molecular formula:

C6H8N2

IUPAC Name:

benzene-1,2-diamine

Details on test material:

- Name of test material (as cited in study report): o-phenylenediamine (PDA)
- Source: Aldrich Chemical Co.
- Analytical purity: 98%.
- Radiochemical purity (if radiolabelling): 98%. (for binding studies only)
- Specific activity (if radiolabelling): 4.75 mCi/mmol. [14C]o-phenylenediamine was from Pathfinder Laboratories

Radiolabelling:

yes

Remarks:

[14C]o-phenylenediamine

Test animals

Species:

human

Administration / exposure

Type of coverage:

open

Vehicle:

other: Aqueous

Duration of exposure:

No data

Doses:

0.5 mL over 1.13 cm2 of exposed skin

No. of animals per group:

No data

Results and discussion

Any other information on results incl. tables

The percutaneous absorption of p-PDA, 2-nitro-p-PDA, 2 -amino-4 -nitrophenol, 4 -chloro-m-phenylenediamine, and 4 -amino-2 -nitrophenol were also tested in this study. The octanol/water partition coefficients were generally in the same rank order as the permeability constants. Preliminary stratum corneum/water partition studies resulted in values that were in the reverse order of skin permeation. When binding of the compounds to components of the membrane were saturated, the partition values more closely duplicated the rank order of permeability of dyes.

Percutaneous Absorption of Hair dyes

Compound	Octanol/water partition coefficient	Stratum corneum/water partition coefficient	Permeability constant cm/h
o-phenylenediamine	1.4	6.9	4.5 x10^-4

 

Dependence of Km on Concentration of o-phenylenediamine

Initial Concentration		Equilibrium Concentration		Km (bound/free)
(DPM/10uL)	(M x 10^5)	Bound (M x 10^4)	Free (M x 10^5)
80462	77.2	46.9	68.4	6.86
36685	35.2	27.5	29.5	9.32
11393	10.9	14.6	8.01	18.2
3723	3.57	6.30	2.33	27.0
1372	1.32	2.69	0.79	34.2
474	0.45	1.09	0.24	45.0

Applicant's summary and conclusion

Conclusions:

Prediction of the percutaneous absorption of a substance based on its partition coefficient may be confounded if the compound is capable of binding to the skin.