A new method to improve penetration depth of dyes into the follicular duct: potential application for laser hair removal.
BACKGROUND
Many persons seek to decrease hair growth and hair density. Although a variety of epilating methods are available, a practical and permanent hair removal treatment is needed.


OBJECTIVE
The purpose of this study was to evaluate a new method of obtaining a better penetration depth of dyes into the follicular duct. By increasing both the quantity and the penetration depth of dye into the follicular duct, the efficacy of laser hair removal could be improved.


METHODS
Dye penetration depth was assessed histologically after the use of formulations containing rhodamine-6G-loaded microspheres dispersed into two different silicones. Each formulation was tested on two hairless rats. After formulation application, dye diffusion was realized by applying ethanol on the skin to extract rhodamine-6G from microspheres.


RESULTS
In all our experimental conditions follicular targeting occurred. No difference in the penetration depth of rhodamine-loaded microspheres was seen between our different silicone formulations. After ethanol application, the penetration of rhodamine-6G into the hair follicle was considerably increased by the fluid silicone vehicle (vs volatile silicone).


CONCLUSIONS
This new galenical approach aims to transport a dye into the hair follicle specifically and deeply. By using adequate laser, the efficiency of laser hair removal could be increased.
Sumian
C C
CC
Galderma Research and Development, French National Institute of Health and Medical Research, Lille, France.
Pitre
F B
FB
Gauthier
B E
BE
Bouclier
M
M
Mordon
S R
SR
D000818:Animals; D004396:Coloring Agents; D018859:Hair Follicle; D006204:Hair Removal / Q000379:methods*; D053685:Laser Therapy; D008863:Microspheres; D051381:Rats; D011923:Rats, Nude; D017207:Rats, Sprague-Dawley; D012235:Rhodamines
D004396:Coloring Agents; D012235:Rhodamines; C026188:rhodamine 6G