Modeling of controlled-release drug delivery systems: Development of parallel algorithms and their implementation on Beowulf clusters.
详细信息
文摘
The impact of bioerodible devices on medical and other applications has steadily increased in the past few decades. The controlled release of these devices is essential especially in medical and pharmaceutical applications like drug delivery, implants, tissue engineering and orthopedics. Controlled drug delivery is the process of combining a pharmaceutical drug with a polymer in such a way that the drug is released from the polymer when the polymer degrades. Since the rate of polymer degradation is related to the rate of drug release into the system, it is of great importance that the polymer degradation be well controlled and designed such that the drug is released at the desired rate of administration. The release (or dissolution) rates of these bioerodible devices are primarily dependent on factors such as intrinsic dissolution rates of its components, porosity, average size of pores, phase dispersion and geometry.;We have developed two computational models that can be used to describe more accurately the dissolution process in an M-component bioerodible device (i.e., M-1 drug components and a porous or non-porous polymer matrix). These models not only extend the previous ones to three dimensions but also include the modeling of bulk erosion in addition to the modeling of surface erosion. Bulk erosion is simulated by the hydration and saturation processes, which have been included as additional steps leading to dissolution. In the first computational model, hydration is modeled as invasion percolation while in the second one hydration is modeled as Fickian diffusion.;Two interacting cellular automata have been used to model the hydration and dissolution processes. The implementation of the new models was carried out on a Beowulf cluster of computers. An effective parallel algorithm has been developed to implement the models and issues such as load balancing, scalability and performance have been considered. Our simulator is portable and has very good scalability. Performance analysis shows that we get excellent speedup and efficiency even for a very large number of processors, if the cellular array size is large enough. The new models provide a powerful simulation tool that can be used for the design of controlled-release pharmaceutical drugs.