PEG/PLA core/shell particles from coaxial electrohydrodynamic spray drying

Abstract

The process of encapsulation has been used to provide a useful route for the delivery of active ingredients in the food and pharmaceutical industries. These fields often employ spray drying processes, where pressurized air flow is used to conveniently prepare microparticles. Unfortunately, spray drying methods do not allow strict control of the particle size and structure. On the other hand, electrohydrodynamic jetting is versatile with regards to controlling these properties. In this work, a combination of spray drying and electrospraying has been used to prepare poly(ethylene glycol) (PEG)/polylactide (PLA) core/shell microparticles. A high electrical potential, which provides controllability, was applied to a customized coaxial nozzle in a laboratory scale spray dryer. Compared to conventional spray drying, the proposed method resulted in the suppression of particle aggregation, improved core/shell structure, smaller particle size, and a decrease in the initial burst release behavior. The solution flow rate and solvent evaporation rate provide additional control of the relative thickness of the core and shell phases, particle size, and aggregation. The combined method of ‘electro-spray drying’ offers an advanced and versatile platform for preparing encapsulated particles that are used widely in the pharmaceutical, food, environmental and electrical industries.