Solid free-form fabrication of drug delivery devices

Three-dimensional printing (3DP) is used to create resorbable devices with complex concentration profiles within the device. 3DP is an example of a solid free-form fabrication method where both the macro- and microstructure of the device can be controlled since objects are built by addition of very small amounts of matter. Application of this novel technology for fabrication of polymeric drug delivery systems is described in this article. The drug concentration profile is first specified in a computer model of the device which is then built using the 3DP process. Complex drug delivery regimes can be created in this way, such as the release of multiple drugs or multiphasic release of a single drug. This study demonstrates several simple examples of such devices and several construction methods that can be used to control the release of the drugs. Two dyes are used as model drugs in a matrix of biocompatible polymers. The dye release rate and release time are controlled by either specifying the position of the dye within the device or by controlling the local composition and microstructure with the 3DP process, The mechanism of resorption can also be controlled by manipulating the composition and microstructure of the device during construction. Polyethylene oxide and polycaprolactone were selected as matrix materials and methylene blue and alizarin yellow were used as drug models. Devices with erosion and diffusion controls are described in this report. Spectrophotometric analysis of dye release yielded reproducible results.