Formation of disaggregated polymer microspheres by a novel method combining pulsed voltage electrospray and wet phase inversion techniques

Abstract

Polymer microspheres with controlled sizes have attracted interest due to their potential use in medical field. Therefore it is of great importance to be able to produce a large number of disaggregated microspheres with a narrow diameter distribution. This work describes the successful elaboration of the method combining electrospray and wet phase inversion for the manufacturing of such polymer microspheres with mean diameters of 2 – 15 µm. Their recovery and drying are easy and they can be directly applied afterwards. The method is universal enough to produce microspheres from various polymers (polycaprolactone, polyethersulfone) and different solvents (dimethylformamide, N-methylpyrrolidone). It was noticed on the basis of microscopic images and using the nitrogen adsorption–desorption method that the specific surface of the microspheres differs depending on the polymer and solvent used. The work introduces additional parameters resulting from the use of pulsed voltage in the electrospray (pulse frequency f and duration τ) which results in better process control. As an example of the use of microspheres as drug carriers, they were loaded with rhodamine and its release was tested. Such microspheres could be dispersed in polymer solution and used in extrusion-based techniques (electrospinning, 3D printing) to form novel complex drug delivery systems.