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-lactide) (PDLLA) and poly(1,5-dioxepan-2-one) (PDXO). The addition of PDXO to PDLLA yielded a more pliable and versatile matrix, where the properties can be controlled by means of composition. The components were fully miscible and formed homogeneous, amorphous, smooth and dense microspheres. Blend composition was a vital factor in determining the blend properties, morphology and in vitro degradation. Diclofenac sodium, a non-steroidal anti-inflammatory drug, was incorporated into PDLLA-PDXO microspheres of various composition ratios. Sustained release of drug was obtained. The degradation and release rates of PDLLA-PDXO microspheres were dependent on the blend composition, providing a powerful means of controlling drug delivery.