Preparation of ethyl cellulose nanoparticles from nano-emulsion obtained by inversion at constant temperature

A new method for the preparation of nanoparticles from nano-emulsions using a low-energy emulsification method based on phase inversion at constant temperature (catastrophic inversion) is described. This method does not require any special equipment such as high-pressure homogenisers. The method is demonstrated for the preparation of ethyl cellulose nanoparticles containing pyrene (a microviscosity and micropolarity probe) as a hydrophobic model molecule. The nano-emulsions were prepared using a combination of non-ionic surfactants: Polyglycerol fatty acid ester (decaglycerol mono laurate) and sorbitan ester (Span 20), volatile organic solvent (toluene) and ethyl cellulose. Toluene was evaporated from the nano-emulsions, resulting in ethyl cellulose nanoparticles 50-120 nm in size. The emission colours of the pyrene-embedded nano-emulsions changed from blue to violet after the evaporation of the toluene because of the absence of excimers. This method may be applied for the preparation of a variety of polymeric nanoparticles in which functional molecules are embedded within the particles.