Numerical modeling of a novel degradable drug delivery system with microholes

Based on UV-LIGA technology, a novel drug delivery microsystem is proposed to eliminate the time lag in initial drug release. With proper microholes in bonding membrane, the drug release rate can be controlled at a stable level in the whole release process. This microsystem is fabricated by degradable polymer and suitable for subcutaneous implants. As a significant parameter, the demarcation time of polymer absorption/erosion is estimated by comparing the experimental results of polymer erosion and in vitro release. By considering diffusion, swelling and erosion mechanisms simultaneously, a numerical drug releasing model is developed to investigate the effect of microholes on drug release and impact factors of linear drug releasing. The simulation results show that the microholes are beneficial to eliminate the time lag, and furthermore, the area of microholes and the initial drug loading have great impact on the release time and the linear drug release rate.