Programmable implants - From pulsatile to controlled release

The aim of this study was to develop programmable implants with a reproducible delayed onset of release followed by several weeks of controlled release. For this purpose, a drug-loaded core was embedded into a drug-free bulk-eroding poly(D,L lactic-co-glycolic acid) or poly(D,L lactic acid) mantle. The manufacturing procedure was established and optimized for three mantle materials, which showed delay times ranging from 7 to 83 days. Triglycerides with fatty acid chain lengths from C-12 to C-18 were investigated as core materials, producing release periods from 2 to 16 weeks. Concomitantly, applying a convolution/deconvolution model showed the possibility of theoretical prediction of the resulting release profiles. (c) 2006 Elsevier B.V. All rights reserved.