184 JOURNAL OF COSMETIC SCIENCE Results and conclusions: The rate and extent of3H2O desorption by the nail samples at each RH was calculated in terms of adsorption volume, v, expressed as (g of water) / (g of dry tissue). Figure 2 shows that the amount of tritiated water desorbed from nail plates decreased with the decrease in water activity. Preliminary analysis of these data using a mathematical solution for desorption of a solute which is uniformly distributed in a homogenous membrane, into a stirred solution with sink conditions, 2 yields diffusivity values from 7.3 X 10-10 cm2/s (for aw= 0.15) to 3.6 X 10- 1 cm2/s (for aw = 1) thus hydration increased diffusivity of water in nail. The desorption rate obtained is a combination of diffusion in the nail tissue and diffusion in vapor phase. A more detailed analysis accounting for the time lag in the vapor phase and tritium exchange with nail proteins is underway. 0.25 • ::I • :! 0.2 � "Cl - 0 en 0.15 .,, ftl E .::: 0.1 ftl -.! 0 :a.as ftl g a a References: 5 10 15 Hour 112 20 Figure 2: Desorption of 3H 2 O from human cadaver nail plates 25 ■Aw-1 □AW-0.89 e Aw-0.8 OAw-0.6 AAWl=OA 6AW-0.27 30 I. Robinson R. A., and Stokes R.H. eds. In Electrolyte solutions, the measurement and interpretation of conductance, chemical potential, and diffusion in solutions of simple electrolytes. Pp 476-492. Butterworth, London (1970). 2. Cooper E.R., and Bemer B. Skin permeability. In Methods in skin research. Pp 407-432. John Wiley and Sons, New York (J 985).

2005 ANNUAL SCIENTIFIC MEETING 185 NANO-SIZED HYBRID CAPSULES BASED ON CYCLODEXTRIN ESTERS: A TOTALLY NEW FLUIDIC ORGANIZATION FOR PENETRATION ENHANCEMENT OF COSMETIC ACTIVE COMPOUNDS Janice Hart*, Delphine Rival', N. Terry2, S. Bonnett, C. Buffevant1 and E. Perrier 1 1 Engelhard-Lyon, 32 Rue St. Jean de Dieu, F-69366, Lyon, France 2 /BCP, CNRS UPR 412, Impasse du Vercors, 69367, Lyon, France delphine. rival@engelhard.com *Janice Hart is presenting on behalf of Engelhard-Lyon Nanotechnologies promised for human being future, a better life as far as health management and medical applications are concerned. Cosmetic companies have been, in this area, one step ahead and have already developed fantastic applications using nanocapsules or nanospheres that are not yet used in the pharmaceutical area. The aim of our study was to develop a chemically modified cyclodextrin that would be able to associate spontaneously into nano-size range biovector, able to mimic the fluidic membrane of liposomes, and able to stimulate the penetration of encapsulated active compounds. The concept of this development was linked with the idea that such type of biovector would induce a double encapsulation system, the encapsulated active compounds being both in the cavity of the cyclodextrin and inside the nanoparticle formed with those nanostructures as well. The tluidic membrane of this biovector enhances the penetration ability. Methods and Results: Progressive chemical esterification was employed using 3 to 15 equivalent of )auric fatty chains for one equivalent of beta-cyclodextrin. Nanoparticles were produced using the solvent evaporation technique. They were analysed for their size (N4 Plus, Beckman Coulter), their shape (using Atomic Force Microscopy, Explorer Thermomicroscope) and for their encapsulated active compounds using conventional HPLC techniques. Penetration of encapsulated active compounds (catechol, 0.1 %, p/p) between those structures (called CYCLOCAPS®, Engelhard, Lyon, France), was then compared with a solution of free catechol and standard liposomes, using Franz cell diffusion devices and rat skin biopsies. Diffusion of each product was estimated at 5, IO and 24 hours by measuring fluorescence (276/298) in the medium in the lower compartment of the Franz cell constituted by PBS with ethanol 80/20. Comparison or the diffusion or catechol in its rree and liposorne forms and encapsulated in CYCLOCAPS Tlrre (hours) Cyclocaps 24H: • statistically different (p0.05) from free form ,.,. statistically different (p0.01) from liposome form Cyclocaps I OH: *"' statistically different (p0.01) from liposome form Cyclocaps 5H: *statistically different (p0.05) from liposome form