Microspheres from poly(D,L-lactide)/poly(1,5-dioxepan-2-one) miscible blends for controlled drug delivery

Novel biodegradable microspheres were designed from blends of poly(D,L-lact ide) (PDLLA) and poly(1,5-dioxepan-2-one) (PDXO). The addition of PDXO to P DLLA yielded a more pliable and versatile matrix, where the properties can be controlled by means of composition. The components were fully miscible a nd formed homogeneous, amorphous, smooth and dense microspheres. Blend comp osition was a vital factor in determining the blend properties, morphology and in vitro degradation. Diclofenac sodium, a non-steroidal anti-inflammat ory drug, was incorporated into PDLLA-PDXO microspheres of various composit ion ratios. Sustained release of drug was obtained. The degradation and rel ease rates of PDLLA-PDXO microspheres were dependent on the blend compositi on, providing a powerful means of controlling drug delivery.