The 24-hour in vitro hairless rat skin permeability study of the 1-day　fentanyl transdermal formulations marketed in JapanFentos®　Tape and OneDuro® Patch　

Context: Two 1-day fentanyl transdermal formulations (FTFs)Fentos® Tape of gum base and OneDuro® Patch of
acrylate baseare marketed in Japan.
Objective: To examine the effects of skin surface temperature and abrasion, as well as adhesive bases on the hairless
rat skin permeability of fentanyl.
Materials and Methods: Permeability was examined in vitro for 24 hours under the following study conditions: skin
surface temperatures (32, 37, and 40C) and skin abrasion (intact and abraded). The flux (Js) rates of fentanyl were
calculated. Furthermore, Arrhenius plots were constructed to examine the correlation between skin permeability and
skin surface temperature.
Results: We compared the Js values of these FTFs in the intact and abraded skin at 32C. Consequently, FTFs
showed the significantly higher (P < 0.05) Js values in the abraded skin than in the intact skin. The slope was steeper
for Fentos® Tape than for OneDuro® Patch.
Discussion and Conclusion: The effects of skin surface temperature on skin permeability were greater for Fentos®
Tape than for OneDuro® Patch. Compared to skin intactness, the influences of skin abrasion on skin permeability of
fentanyl were greater for both FTFs. Heed needs to be given to skin conditions when using these FTFs in clinical
practice.

JOURNAL OF DRUG DELIVERY RESEARCH, Volume 4 Issue 3(2015)