Supercritical fluid extraction of emulsions to produce biopolymers microparticle and nanoparticle

Supercritical fluids extraction of emulsions (SEE) is an innovative technique used for the production of micro, nano-particles with controlled size and distribution. Supercritical carbon dioxide (SC-CO2) is used to extract selectively the organic solvents from the droplets of the emulsion, in which the biopolymer is dissolved, producing the precipitation of the polymer and the subsequent formation of particles. In the SEE technology, the dimensions of the desired polymeric particles are directly connected to the dimensions of the droplets in the emulsions, indeed changing the emulsion formulation parameters it is possible to vary the dimensions of the particles produced after the solvent removal. SEE technology was also developed in continuous operation layout (SEE-C) to improve the product recovery and processing. In our previous work, SEE-C technology was successfully applied to produce microparticles starting from a new emulsion preparation method using acetone as the solvent of the dispersed phase in place of common used solvents (ethyl acetate, methylene chloride, chloroform). Only particles in the micrometric range of dimensions were produced by SEE-C technology starting from this new emulsion formulation. The aim of this work is to try to establish the conditions at which by SEE-C is possible to vary the dimensions of the particles form micro size range to nano size range. This work focuses on particle engineering from microparticles to nanoparticles for different biopolymers, changing the formulation of the emulsion using acetone as disperse solvent. Varying the emulsion formulation parameters such as, surfactant and biopolymer amount, phases ratio and emulsification technique (ultrasound or high speed emulsification), droplets dimensions have been changed from the microsize to the nanosize range, allowing the production of micro and nanoparticles of PMMA (poly-metylmetacrylate) and PCL (poly-caprolactone) of desired size and distribution after supercritical solvent extraction.