Controlled ring-opening polymerization of lactones and lactides

1,5-dioxepan-2-one (DXO) is presented as a versatile component in biodegrad able polymers for biomedical applications. Copolymerization of DXO and L-la ctide yielded a semi-crystalline, yet flexible, material where the extent o f crystallinity and erosion characteristics were controlled by an appropria te choice of copolymer composition. Crosslinked PDXO was polymerized as a n ovel biodegradable elastomer. The degradation behavior of these materials w ere explored in vitro. Microspheres from poly(DXO-co-L-LA) were prepared an d shown to be promising candidates for controlled release. The polymer comp osition and drug solubility provided effective means of controlling the dru g delivery pattern.