Registration Dossier

Administrative data

Endpoint:
cytotoxicity
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well described

Data source

Reference
Reference Type:
publication
Title:
Development of an in vitro primary screen for skin depigmentation and antimelanoma agents
Author:
Dooley T.P. , Gadwood R.C. , Kilgore K. and Thomasco L.M.
Year:
1994
Bibliographic source:
Skin Pharmacology, 7(4), 188-200.

Materials and methods

Principles of method if other than guideline:
In vitro cell culture system with spontaneously immortalized murine melanocyte lines that growth rapidly in culture and produces copious amounts
of melanine, was treated with PDMB and similar compounds. This method evaluate the ability of compound to inhibiting melanogenesis or to cause
melanocyte/melanoma cell death, by measuring the spectrophotometric means of melanin after 5 days of treatment.
GLP compliance:
not specified
Type of method:
in vitro

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
The substance is commercially product, provided by Aldrich Chemical Co., Milwaukee, Wisconsin.

Test animals

Species:
mouse
Strain:
C57BL
Sex:
not specified
Details on test animals and environmental conditions:
In vitro test:
a  C57BL/6 mouse-derived spontaneously immortalized melanocyte cell line

Administration / exposure

Route of administration:
other: in vitro
Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
See details below
Frequency of treatment:
See details below
Post exposure period:
See details below
No. of animals per sex per dose:
Not applicable

Results and discussion

Details on results:
The Mel-Ab melanocyte cell line was exposed to test material for 5 days.  Vehicle was 50% propylene glycol, 30% ethanol and 20% water. Melanin 
content and cell survival were measured Comments All materials were  tested at 0.01-1000 ug/ml. The inhibitory concentration of 50% values for 
PDMB on melanocyte cell  line (Mel-Ab) is 280 µg/mL. This IC50 value represents the concentration  at which melanine biosynthesis has decreased 
by one half, relative to  vehicle control treated cells. That means a reduction in either  depigmentation directly on cytotoxic or cytostatic effect of 
compounds on  total cell number. An IC50 exceeding or equal to 100 µg/mL was considered  as inactive. The PDMB was by consequence considered as inactive for the depigmentation  of this melanocyte cell lines (Mel-Ab) or for the cytotoxic or cytostatic  effect. Comparing this result with the 
active hydroquinone effects, the authors  concluded that the decreased oxidation potential of di-methoxy analogs  relative to di-hydroxy 
compounds accounts for the reduction of  cytotoxicity.

Applicant's summary and conclusion