Cc. Sumian et al., A new method to improve penetration depth of dyes into the follicular duct: Potential application for laser hair removal, J AM ACAD D, 41(2), 1999, pp. 172-175
Background: Many persons seek to decrease hair growth and hair density. Alt
hough a variety of epilating methods are available, a practical and permane
nt hair removal treatment is needed.
Objective: The purpose of this study was to evaluate a new method of obtain
ing a better penetration depth of dyes into the follicular duct. By increas
ing 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 tw
o different silicones. Each formulation was tested on two hairless rats. Af
ter 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 applicatio
n, the penetration of rhodamine-6G into the hair follicle was considerably
increased by the fluid silicone vehicle (vs volatile silicone).
Conclusion: This new galenical approach aims to transport a dye into the ha
ir follicle specifically and deeply By using adequate laser, the efficiency
of laser hair removal could be increased.