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 examp le of a solid free-form fabrication method where both the macro- and m icrostructure 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 desc ribed in this article. The drug concentration profile is first specifi ed 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, su ch 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 rele ase of the drugs. Two dyes are used as model drugs in a matrix of bioc ompatible polymers. The dye release rate and release time are controll ed by either specifying the position of the dye within the device or b y controlling the local composition and microstructure with the 3DP pr ocess, The mechanism of resorption can also be controlled by manipulat ing the composition and microstructure of the device during constructi on. Polyethylene oxide and polycaprolactone were selected as matrix ma terials and methylene blue and alizarin yellow were used as drug model s. Devices with erosion and diffusion controls are described in this r eport. Spectrophotometric analysis of dye release yielded reproducible results.