| 摘要 |
The present invention is a method to produce novel composites based on microcapsules or microspheres embedded in contiuous polymeric matrices. Both non-bioerodible and erodible polymers can be used. Material can be incorporated into the microcapsules or microspheres for subsequent release. In one embodiment of the present invention, spheres are homogeneously dispersed in a polymer matrix and then forced to release their contents by exposure to temperature, light or ultrasound. Alternatively, polymers which degrade as a function of time or hydrolysis can be used for controlled releases. The polymer composites have completely different properties from either a continuous polymer matrix or microcapsules or microspheres and are therefore useful for a wide variety of applications. When carbon tetrachloride is the incorporated material, the film is useful as a flame retarding device. When foaming agents are used, especially UV or heat sensitive materials, gas can be evolved inside each capsule to form bubbles in the polymer. When a drug or other bioactive agent is incorporated in the spheres and encapsulated with the polymer, release occurs only through the eroded or ruptured spheres. In contrast to release from encapsulated microcapsules, release from the polymer composite is approximately linear with time. Erosion of the polymer spheres can also be used to create a porous polymeric structure. This kind of device can be used in transdermal drug delivery, vascular grafts, wound-healing films, or as a polymeric porous membrane.
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