The Shape, Size and Uniformity Control of Biodegradable Poly(lactic-co-glycolic acid) Micro-Particles Produced by Electrospraying Method

Hypothesis: Nowadays, the growing concern over environmental pollution has attracted attentions towards development of biodegradable micro-particles to replace non-degradable micro-particles used in cosmetic products. In this regard, poly(lactic-co-glycolic acid) (PLGA) micro-particles produced by a simple technique, electrospraying, is used as biodegradable micro-particles. To obtain the maximum efficiency, especially as a drug delivery system, these particles need to be fiber-free with spherical shape and have a uniform size distribution. This goal can be achieved by controlling variables such as polymer molecular weight, solvent type, polymer solution concentration, voltage, needle size, polymer solution feed rate and distance from needle tip to collector. Methods: PLGA particles were electrosprayed considering four variables, including polymer solution concentration (at three levels), needle size (at two levels), voltage (at three levels), and polymer solution feed rate (at three levels). Then, electron scanning microscopic images were obtained from each sample to observe the morphology of particles and to study the effect of process variables on it. To understand the morphological behavior of the particles, the influence of each variable was investigated according to mechanisms involved in electrospraying process. Findings: The four variables affecting droplet size, and consequently, Peclet number and droplet charge play important roles in mechanisms involved in electrospraying process and determining the morphology of the resultant particles. Thanks to the effects of these phenomena, spherical and fiber-free micro-particles with uniform size were obtained by electrospraying PLGA solutions at concentrations of 3% and 5%, using a 27 G needle at a feed rate of 0.3 mL/h and applying a voltage of 10 kV.