Biodegradable Poly(D,L-lactide)/Lipid Blend Microparticles Prepared by Oil-in-Water Emulsion Method for Controlled Release Drug Delivery

The effects of blend ratio and drug loading content of poly(D,L-lactide) (PDLL)/stearic acid blends on microparticle characteristics and drug release behaviors were evaluated. The blend microparticles were prepared by an oil-in-water emulsion solvent evaporation method for drug delivery of a poorly water-soluble model drug, indomethacin. The microparticles were characterized using a combination of scanning electron microscopy (SEM), light scattering particle size analysis, differential scanning calorimetry (DSC) and UV-vis spectrophotometry. The blend microparticles with a PDLL/stearic acid blend ratio in the range 100/0-95/5 (w/w) exhibited a spherical shape with a smooth surface. Blend microparticles with a similar size (167-177 μm) and drug loading efficiency (60-67%) were obtained. The drug loading content did not affect the characteristics of the blend microparticles. An in vitro drug release test demonstrated that the level of drug release decreased as the stearic acid blend ratio increased and the drug loading content decreased. The overall results indicated that it was possible to use PDLL/stearic acid blend microparticles as a controlled release drug delivery system.