Preparation of poly(propylene carbonate-co-ε-caprolactone) and their applications in drug delivery

An aliphatic poly(propylene carbonate-co-epsilon-caprolactone) (PPCCL) was synthesized by terpolymerization of CO2, propylene oxide, and epsi;-caprolactone (CL) using SalenCo(III)(2,4-dinitrophenoxy) (Salen = N, N-bis (3,5-di-tert-butylsalicylidene)-ethylenediimine) (1)/1,10-phenanthroline monohydrate catalyst system. The obtained terpolymers were characterized by IR and H-1 NMR to determine its structure. The reactivity ratios of CO2 and CL (r(CO2) = 6.54 and r(CL) = 0.22) were evaluated by Fineman-Ross methodology. The reaction conditions were optimized according to the factors affecting the terpolymerization. The results indicated that the polymer yield is high to 7.15 g using 0.1 mmol complex 1 for 10 h. Using the PPCCL as the carrier, PPCCL microcapsule was prepared through solvent volatilization. The stirring speed had a significant effect on morphology and particle size of PPCCL microcapsules. The composition of terpolymer had little effect on morphology and particle size of PPCCL microcapsules. However, the rate of imidacloprid release from the microcapsules was accelerated with the amount of polyester component in terpolymer increasing.