Supercritical antisolvent micronization of some biopolymers

We processed various biopolymers by semi-continuous supercritical antisolvent precipitation (SAS) to evaluate the possibility of producing nano and micro-particles of controlled size and distribution. First, some liquid expansion curves were experimentally produced to study the general behavior of the ternary systems antisolvent-solvent-biopolymer. A condition that guarantees a successful SAS micronization is that solute does not modify the expansion curves of the solvent-antisolvent binary system. SAS experiments were performed by varying the process parameters; we mainly studied the influence of pressure, temperature and liquid solution concentrations. SEM images of the processed material were used to study morphologies, mean particle size and particle size distribution. We successfully processed by SAS dextran, poly-l-lactide (PLLA) and poly-(hydroxypropylmethacrylamide) (HPMA), using dimethylsulfoxide (DMSO) and dichloromethane (DCM) as liquid solvents.