Synthesis of biodegradable triple-layered capsules using a triaxial electrospray method

An electrospray system incorporating a triaxial capillary device was used to fabricate biodegradable, multi-shell capsules for use as a drug delivery system. Triple-layered capsules composed of poly(lactic-co-glycolic acid) (PLGA) and poly(DL-lactic acid) (PDLLA) were synthesized by electrospray drying and the formation and characteristics of the capsules were studied under a variety of experimental conditions. The size distribution and morphology of the capsules were determined using phase-Doppler particle analysis (PDPA), field emission scanning electron microscope (FE-SEM), and laser scanning confocal microscopy. To demonstrate flexible control and release of multiple drugs and combined prescriptions, drug release rates from multi-shell capsules containing paclitaxel and doxorubicin were evaluated by high-performance liquid chromatography (HPLC). Monodisperse, triple-layered capsules containing anti-tumor agents were synthesized in one step. The size and shell thickness of the capsules were independently controlled by changing the flow rate and polymer concentration of the solution used to fabricate each shell. It was also shown that these multi-shell capsules reduced initial burst release and that capsule swelling and drug-diffusion times could be managed by controlling polymer concentrations in the triple-layered structure.