In vitro enzymatic degradation of the cross-linked poly(ε-caprolactone) implants

The cross-linked poly(ε-caprolactone) (PCL) implants were directly prepared via the ring-opening polymerization of CL with cross-linker (BTB). The in vitro enzymatic degradation of the resulting implants was performed with Thermomyces lanuginosus lipase. We saw that the cross-linked PCL implants degraded in lipase via the surface erosion mechanism. The higher the molar ratio of monomers to catalyst or the higher the cross-linker amount in feeding dose, the slower the degradation rate of the cross-linked PCL implants. Moreover, the degradation rate of the cross-linked PCL implants was lower than that of the uncross-linked ones, which could markedly reduce the acidic degradation products. The macroscopic observation results indicated that the cross-linked PCL implants had good form-stability. The changes in thermal properties showed that the degradation occurred in both amorphous and crystalline regions. The results implied that the highly cross-linked PCL implants had great potential as controlled drug release agents.