Article abstract


Nature Materials 2, 767 - 772 (2003)
Published online: 19 October 2003 | doi:10.1038/nmat998

Subject Categories: Polymers | Biomedical materials

Multi-pulse drug delivery from a resorbable polymeric microchip device

Amy C. Richards Grayson1,5, Insung S. Choi2, Betty M. Tyler3, Paul P. Wang3, Henry Brem3, Michael J. Cima1 & Robert Langer4


Controlled-release drug delivery systems have many applications, including treatments for hormone deficiencies and chronic pain. A biodegradable device that could provide multi-dose drug delivery would be advantageous for long-term treatment of conditions requiring pulsatile drug release. In this work, biodegradable polymeric microchips were fabricated that released four pulses of radiolabelled dextran, human growth hormone or heparin in vitro. Heparin that was released over 142 days retained on average 96 plusminus 12% of its bioactivity. The microchips were 1.2 cm in diameter, 480–560 mum thick and had 36 reservoirs that could each be filled with a different chemical. The devices were fabricated from poly(L-lactic acid) and had poly(D,L-lactic-co-glycolic acid) membranes of different molecular masses covering the reservoirs. A drug delivery system can be designed with the potential to release pulses of different drugs at intervals after implantation in a patient by using different molecular masses or materials for the membrane.

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  1. Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
  2. Department of Chemistry, School of Molecular Science – BK21, and Center for Molecular Design and Synthesis, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
  3. School of Medicine and Department of Neurosurgery, Johns Hopkins University, 817 Hunterian, 725 North Wolfe Street, Baltimore, Maryland 21205, USA
  4. Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Bldg E25-342, Cambridge, Massachusetts 02139, USA
  5. Present address: School of Chemical and Biomolecular Engineering and the Biomedical Engineering Program, 120 Olin Hall, Cornell University, Ithaca, New York 14853, USA

Correspondence to: Robert Langer4 e-mail: rlanger@mit.edu



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