SYNTHESIS OF POLY(1,4-DIOXAN-2-ONE-CO-TRIMETHYLENE CARBONATE) FOR APPLICATION IN DRUG-DELIVERY SYSTEMS

Poly(1,4-dioxan-2-one-co-trimethylene carbonate), P(DON-co-TMC), copol ymers with different compositions were synthesized by copolymerization s of 1,4-dioxan-2-one (DON) and trimethylene carbonate (TMC) at 120 de grees C in the presence of Sn(Oct)(2). Their structures and compositio ns were determined with FT-IR and H-1-NMR spectroscopies. The intrinsi c viscosities of copolymers increased with the increase of the TMC fra ction in feed. The DSC results of copolymers showed that the glass tra nsition temperatures (T(g)s) of copolymers are lower than those of hom opolymers. Most copolymers ape amorphous except for one with a high DO N composition. The hydrophilicity of the copolymers is in proportion w ith the DON molar fraction in the copolymers. It was found that the Le vonorgestrel (LNG) release rate is dependent of the composition and fl exibility of polymer chains. The fastest one is the copolymer with nea rly a equivalent fraction of DON to TMC. Among copolymers with other c ompositions, a higher DON fraction would be favorable to the release o f LNG. All measurements demonstrate an almost constant release rate in the period of 1 month. (C) 1998 John Wiley & Sons, Inc.