Serge Mordon

Experimental evaluation of site-specific delivery of methylene blue to the hair follicles using fluorescence imaging

This study aimed to evaluate the penetration of Methylene Blue (MB)-loaded microspheres into the follicular ducts of rats. MB was incorporated into porous nylon microspheres which have a size of 10 ?m (Orgasol 4000 Nat Cos, Elf-Atochem, France). The microspheres were dispersed into fluid silicone. Male hairless rats (NU, Iffa Credo, France; mutant hairless Sprague Dawley rat) were used to evaluate the penetration of MB into hair follicles. After formulation application, MB diffusion was induced and skin biopsies were realized immediately, 2 hours and 26 hours after MB loaded microspheres application. All samples were snap frozen in liquid nitrogen and processed stored at -80°C before embedded in TissuTek and cryostat-cut. 14?m sections were realized. MB fluorescence was observed with Eclipse E800 microscope (Nikon, Tokyo, Japan) expanded for fluorescence microscopy (with FITC, TRITC and CY5 filters) and penetration depth was quantified using image analysis software (Sigma Pro, Jandel, USA). Autofluorescence was evaluated using FITC and TRITC filter. MB was seen 200?m deep in hair follicles (2 hours after application) and at 600?m (26 hours after application). This galenical approach aims to transport MB into the hair follicle specifically and deeply.

Laser-triggered releasing of fluorescein from thermosensible liposomes: a new method for quantification of laser-induced photocoagulation

The objective of this in-vivo study was to assess the possible use of temperature sensitive liposomes in an established model such as liver as a new approach to monitor the temperature induced by a laser. Temperature sensitive liposomes (DSPC: distearoylphosphatidylcholine) loaded with carboxyfluorescein were prepared by the Bancham procedure. These liposomes (1 ml solution) were injected into adult male wistar rats. Two hours later, the liver was exposed and irradiated with a 100 W Nd:YAG laser using pulses lasting from 100 ms to 260 ms. Simultaneously, the surface temperature was recorded with a thermographic camera. The fluorescence emission was measured with a fluorescent imaging system. The results show that the dye is released in response to laser energy. The amount of the drug release increases linearly with increasing temperature in the range 45 degree(s)C - 60 degree(s)C. Moreover, the release occurs in a short period of time upon brief exposure to its phase transition temperature. The temperature range could be modified and adapted by using different liposomes formulation, for example DPPC (dipalmitoylphosphatidylcholine) for lower temperature (35 - 45 degree(s)C) or DSPE (distearoylphosphatidylethanolamine) for higher temperature (65 - 75 degree(s)C).