Tianning Chen

Modeling and simulation of drug release from multi-layer biodegradable polymer microstructure in three dimensions

Abstract Multi-layer biodegradable polymer drug delivery microstructures with micro-chambers have many exceptional advantages in a long-term controlled drug delivery. In this paper, a mathematical model for the drug release from this type of three-dimensional (3D) drug delivery microstructures is presented by using 3D cellular automata and discrete iterations. The validity of the model is proved by comparing with the Gőpferich’s simulated profiles for the same composite polymer cylinder matrices. Based on this model, furthermore, the simulations are done to describe the dynamic behavior of drug release from this type of microstructures. The simulation results show that this 3D mathematical model can describe accurately the drug release behavior and therefore can provide a new optimal design tool for this kind of multi-layer biodegradable polymer drug delivery microstructure.

Fabrication of biodegradable polymer (PLGA) microstructures and applications in controlled drug delivery

Using biodegradable polymers for implantable drug delivery purposes has been a very important research area and industry for many years. Polymers, such as PLGA, have been the most attractive one because it does not require removal after the drug has been released. We report a research effort to microfabricate high aspect ratio microstructures of PLGA and its potential applications in implantable drug delivery. The prototypes of packaged cells with dyes have also been made and currently under test for linear release of sample dyes.

Study on structural optimum design of implantable drug delivery micro-system

Abstract In this paper, design, modeling, and simulation of a new type of controlled drug delivery system based on biodegradable polymers is report. The system consists of arrays of micro-chambers for drug storage to achieve linear release. The micro-chambers were fabricated with biodegradable polymer using the UV-LIGA technology and the controlled release process is the combined results of design of the micro-chambers and the biodegradable characteristics of the polymer. This type of drug delivery system has some unique advantages in controlled long-term drug delivery, such as improved efficiency, reduced side effect, on-spot delivery, and convenient therapy. Mathematical model has been developed for two kind of biodegradable polymer micro-system respectively, and numerical simulations were conducted to analyze the biodegradation and the controlled release process. The mathematical model can be used to optimize the structural design for controlled-release system with the desired release characteristics.

Modeling the drug release from 3D multi-layer microstructure with micro-chambers

This paper presents a mathematical model for three-dimensional biodegradable multi-layer drug delivery microstructure with large array of micro-chambers. The simultaneous release of multiple drugs from this type of drug delivery microstructure is modeled using cellular automata (CA) and discrete iterations. The model can describe the dynamic behavior of drug release. Furthermore, simulations about this type of drug delivery microstructure enclosed two drugs are carried out. The simulation results show that the introduced mathematical model can act as the basis of a new optimal design methodology for three-dimensional biodegradable multi-layer drug delivery microstructure.

Topology Optimization of MEMS-Based Biodegradable Controlled Drug Delivery System for Combination Therapy

MEMS-based biodegradable controlled release system with micro multi-chambers can respectively enclose two drugs in different chambers to realize a combination therapy. In order to synchronously obtain the linear release of two drugs, it is necessary to completely investigate the topology optimization of the system. This paper introduces the theory of multi-objective topology optimization into MEMS-based biodegradable controlled release system for the combination therapy. Furthermore, a new method of CA-based evolutionary structural optimization (CA-ESO) is presented to accomplish the topology optimization of this controlled release system. The result shows that the optimized drug delivery system can achieve the objective of the synchronizing linear release for two drugs. The conclusion illustrates that the CA-ESO method proposed in this paper is validity for the topology optimization of MEMS-based biodegradable controlled release system.Copyright

Design of controlled drug delivery system with optimal release characteristics

The biodegradable controlled-release system with large array of micro chambers is a new controlled drug delivery system. The structure of the system is designed using the MEMS technology, combining the drug release condition and the biodegradable characteristic of the polymer. This type of drug delivery system has some unique advantages in controlled long-term drug delivery, such as more drug loading than the matrices release systems, easier control the release rate, and so on. It is necessary to optimum the structure for the long-term drug delivery. This paper founds the simulated modeling which can simulate the erosion and the drug delivery from this controlled-release system. Further more the thickness of the chambers wall is taken as the design variable. An optimized modeling for the drug delivery from the biodegradable controlled-release system is developed. This model can optimize the structure of the controlled release system for the desired release characteristics. The results indicate that this method can be used to design the drug delivery system based on the biodegradable polymer.

Study on the packaging integrity testing for polymer micro-device

To test the packaging integrity of high polymer micro-device fabricated by UV-LIGA technique, a new method of non-destructive testing was presented. This method is based on conductance analysis principle of electrochemistry. Dependence on the slight change of the current value in the solution, the packaging integrity of micro-device was measured and the stability of the packaging method was evaluated. The experiment apparatus for the conductance analysis method was built, and applied to test the packaging integrity of the micro-device. The experimental results show that the presented testing method is effective to measure the packaging integrity of the micro-device.