Preparation of organic nanoparticles using microemulsions: their potential use in transdermal delivery.

Organic nanoparticles of cholesterol and retinol have been synthesized in various AOT (Aerosol OT; sodium bis(2-ethylhexyl) sulfosuccinate)/heptane/water microemulsions by direct precipitation of the active principle in the aqueous cores. The nanoparticles are observed by transmission electron microscopy (TEM) using the adsorption of a contrasting agent, such as iodine vapor. The size of the nanoparticles can be influenced, in principle, by the concentration of the organic molecules and the diameter of the water cores, which is related to the ratio R=[H2O]/[surfactant].

Mechanism of formation of inorganic and organic nanoparticles from microemulsions.

This chapter essentially deals with the preparation of nanoparticles using microemulsions. The preparation of inorganic nanoparticles--Ni2B, Pt, Au, Pt-Au, AgX--and the synthesis of organic nanoparticles--cholesterol, rhovanil, rhodiarome--are systematically studied as a function of the concentration of the precursor molecules, the size of the inner water cores, and the manner of mixing the various solutions. Two different behaviors are observed in the various systems.

Synthesis of monodisperse nimesulide nanoparticles in microemulsions E170/isopropyl myristate/water/n-butanol (or isopropanol).

Nanoparticles of nimesulide have been synthesized in two systems of microemulsion: E170/isopropyl myristate/water/n-butanol (or isopropanol). Nanoparticles are monodisperse. In the two microemulsions, the size of the nanoparticles is comprised between 45 and 60 A and also seems to be independent of the factor R ([water]/[E170]) and of the concentration of the nimesulide solubilized in chloroform.