An orthogonal model to study the effect of electrospraying parameters on the morphology of poly (d,l)-lactide-co-glycolide (PLGA) particles

Electrospraying has been recognized as an important technique for the production of microparticles for pharmaceutical applications. Nevertheless, the produce of poly (d,l)-lactide-co-glycolide (PLGA) microspheres with a desired size distribution remains a challenge. We conducted an empirical study, based on a fractional orthogonal design, to optimize the size distribution of electrosprayed particles. The influence of different processing factors, including PLGA concentration in the solution, volumetric flow rate of the solution, travel distance between the needle tip and the collection, voltage applied to the polymer solution, size of the needle, and type of solvent on the electrospraying of polymericmicroparticles was investigated. After electrospraying, the size distribution of the PLGA particles was characterized and analyzed. Among the selected factors, the type of solvent used was the principal factor affecting the particle size of electrosprayed microspheres. Hexafluoro-2-propanol (HFIP) electrosprayed microparticles with the smallest diameter. However, hollowed particles could be seen among these microspheres. Dichloromethane (DCM) was found to electrospray microspheres with a fairly spherical geometry, while trichloromethane (TCM) electrosprayed particles with relatively rougher surfaces. Finally, the particle size of sprayed microspheres decreases somewhat with the polymer concentration and travel distance.