Monodisperse biopolymer nanoparticles by Continuous Supercritical Emulsion Extraction

In this work Continuous Supercritical Emulsions Extraction (SEE-C) has been tested to produce monodisperse biopolymer nanoparticles. The SEE-C technology allows an improved control of particle size distribution by reducing the emulsion processing times and preventing any droplet/particle aggregation. Biopolymers as, poly-lactic acid (PLA), poly-caprolactone (PCL) and poly-lactic-co-glycolic acid (PLGA) in different emulsion formulations were tested using acetone as oily-phase solvent. Emulsion formulation parameters, such as surfactant and/or polymer concentration and emulsification techniques (ultrasound or high speed emulsification) were analyzed in connection to SEE-C, to produce monodisperse nanoparticles. Operating at 38 °C and 80 bar, with an L/G ratio of 0.1, particles of PLA, PCL and PLGA with mean size of 233 nm, 342 nm and 212 nm, respectively, were produced. Poly-dispersity indexes lower to 0.1 nm were also obtained, confirming the possibility to obtain sharp distributions with monodisperse characteristics. Solvent residues as low as 500 ppm were also observed.

Schematic representation of SEE-C process layout and example of biopolymer nanoparticles produced with a mean size of 200 nm and a PDI of 0.07.Figure optionsDownload as PowerPoint slideHighlights
► The Continuous Supercritical Emulsion Extraction process is proposed for the production on monodisperse nanoparticles.
► PLA, PLGA and PCL stable nanoparticles suspensions have been successfully obtained in the range 200–700 nm.
► Optimization of the SEE process parameters allowed to obtain monodispersed particle size distributions.