MRI characterization of implantable drug delivery bioceramics

Ceramic materials implanted into the body for repair or reconstruction of tissues are known as bioceramics. One potential application is the use of porous bioceramics as controlled-release drug delivery devices. Bioceramics with tailored microstructure have potential as long-term and/or variable rate drug delivery vehicles. The success of these materials depends upon the ability to optimize the microstructure so as to release compounds at different stages of healing. Resorbable bioceramic materials offer a solution to this problem, and do not requite secondary surgeries because they are designed to completely biodegrade over time. Calcium Polyphosphate (CPP) is a promising candidate material for continuous long-term localized drug-delivery. The release of drug from CPP matrices is a process that involves a dynamic interplay between the fluid absorbed from the environment and changes due to material degradation. While the use of CPP for the delivery of therapeutic agents has demonstrated significant initial success, challenges remain in terms of extending the release period, tailoring the release rate, and improving the mechanical strength. Alternative processing/fabrication method are being developed; a process that would significantly benefit from a non-destructive technique that could directly provide quantitative feedback about the temporal and spatial evolution of the microstructural and transport properties. Utilizing Magnetic Resonance Imaging (MRI), it is therefore possible to simultaneously characterize both the material degradation process and the fluid/drug transport properties of bioceramics in situ. This program will therefore apply MRI to the characterization of novel CPP drug delivery devices. Studies will simultaneously involve the development and refinement of new MRI techniques, and the application of these methods to drug delivery bioceramics, including direct imaging of the drug itself. Such information is crucial to the development of improved CPP devices. The ability to aid in the advancement of bioceramic technology will lead to new progress in this area, with the long-term clinical success of bioceramics potentially leading to an improved quality of life for millions of Canadians.