title: Multi-pulse drug delivery from a resorbable polymeric microchip device.
abstract: 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 +/- 12% of its bioactivity. The microchips were 1.2 cm in diameter, 480-560 microm 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.
authors: Deaprtment of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, 02139, USA.
authors: Amy C
authors: AC
authors: Richards Grayson
authors: Insung S
authors: IS
authors: Choi
authors: Betty M
authors: BM
authors: Tyler
authors: Paul P
authors: PP
authors: Wang
authors: Henry
authors: H
authors: Brem
authors: Michael J
authors: MJ
authors: Cima
authors: Robert
authors: R
authors: Langer
mesh_terms: D020341:Absorbable Implants; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis* / Q000737:chemistry; D003911:Dextrans / Q000008:administration & dosage; D004334:Drug Administration Schedule; D004337:Drug Carriers / Q000008:administration & dosage* / Q000138:chemical synthesis*; D004339:Drug Compounding / Q000295:instrumentation / Q000379:methods; D004343:Drug Implants / Q000008:administration & dosage / Q000138:chemical synthesis*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D006493:Heparin / Q000008:administration & dosage; D019382:Human Growth Hormone / Q000008:administration & dosage; D019344:Lactic Acid / Q000008:administration & dosage / Q000138:chemical synthesis*; D008904:Miniaturization; D011091:Polyesters; D011108:Polymers / Q000008:administration & dosage / Q000138:chemical synthesis*
chemical_list: D020099:Coated Materials, Biocompatible; D003911:Dextrans; D004337:Drug Carriers; D004343:Drug Implants; D011091:Polyesters; D011108:Polymers; D019382:Human Growth Hormone; D019344:Lactic Acid; C033616:poly(lactide); D006493:Heparin