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Designing multilayered particulate systems for tunable drug release profiles.

Acta biomaterialia (2012-02-22)
Wei Li Lee, Pattara-orn Yu, Meiju Hong, Effendi Widjaja, Say Chye Joachim Loo
ABSTRACT

Triple-layered microparticles comprising poly(D,L-lactide-co-glycolide, 50:50) (PLGA), poly(L-lactide) (PLLA) and poly(ethylene-co-vinyl acetate, 40 wt.% vinyl acetate) (EVA) were fabricated using a one-step solvent evaporation technique, with ibuprofen drug localized in the EVA core. The aim of this study was to investigate the drug release profiles of these triple-layered microparticles in comparison to double-layered (PLLA/EVA and PLGA/EVA) (shell/core) and single-layered EVA microparticles. Double- and triple-layered microparticles were shown to eliminate burst release otherwise observed for single-layered microparticles. For triple-layered microparticles, the migration of acidic PGA oligomers from the PLGA shell accelerated the degradation of the PLLA mid-layer and subsequently enhanced drug release in comparison to double-layered PLLA/EVA microparticles. Further studies showed that drug release rates can be altered by changing the layer thicknesses of the triple-layered microparticles, and through specific tailoring of layer thicknesses, a zero-order release can be achieved. This study therefore provides important mechanistic insights into how the distinctive structural attributes of triple-layered microparticles can be tuned to control the drug release profiles.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Poly(ethylene-co-vinyl acetate), vinyl acetate 40 wt. %, melt index 57 g/10 min (190°C/2.16kg), contains 200-800 ppm BHT as inhibitor
Sigma-Aldrich
Poly(ethylene-co-vinyl acetate), vinyl acetate 25 wt. %, melt index 19 g/10 min (190°C/2.16 kg), contains 200-900 ppm BHT as inhibitor
Sigma-Aldrich
Poly(ethylene-co-vinyl acetate), vinyl acetate 18 wt. %, melt index 8 g/10 min (190°C/2.16kg), contains 200-900 ppm BHT as inhibitor
Sigma-Aldrich
Poly(ethylene-co-vinyl acetate), vinyl acetate 12 wt. %, melt index 8 g/10 min (190°C/2.16kg)