BME 314 Lecture 7 - DrugDeliveryII Krish Roy Ph.D Associate Professor Dept of Biomedical Engineering Controlledrelease:Basickinetics Rate of drug

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Drug Delivery II Krish Roy, Ph.D. Associate Professor Dept. of Biomedical Engineering
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Controlled release: Basic kinetics Rate of drug release from a polymeric device (matrix, particles etc.) can be approximated by three simple types of release kinetics: a. Zero order release: Rate of drug release in independent of the mass of drug remaining in the device E.g.: Osmotic and mechanical pumps, Rate-controlling membranes reservoir controlled release, surface-eroding polymers b. First order release: Rate of drug release is proportional to the amount of drug remaining within the implant E.g.: Bulk eroding polymeric devices c. Square-root of time release: Release rate decreases proportionally to the square-root of time E.g.: Initial release rates from polymeric implants in a tissue
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Controlled release: Basic kinetics t k M k dt dM o t o t = = kt t kt t t t kM dt dM M M M M k dt dM - - = - = - = exp )] exp 1 [ ) ( t k M t k dt dM d t d t 2 = = Zero order kinetics: Rate of release is constant First order kinetics: Rate of release is proportional to the remaining drug Square root kinetics: Rate of release varies as The square root of time
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Non-degradable polymers Implants Oral delivery Membrane-controlled devices (skin patches) Degradable polymers Parenteral, intravenous and mucosal systems Micro and nanoparticles Hydrogels Degradable implants, matrix type Bulk degradation versus surface degradation Polymers in controlled drug release
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Diffusion-controlled systems: Reservoir devices Monolithic (matrix) devices (non-erodible) Solvent-controlled systems: Osmotically controlled devices Swelling-controlled devices Chemically-controlled systems: Drug covalently attached to the polymer backbone Drug in a core surrounded by a bio-erodible rate-controlling membrane. Drug homogeneously dispersed in a bio-erodible polymer
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This note was uploaded on 11/29/2010 for the course BME 314 taught by Professor Frey during the Fall '08 term at University of Texas at Austin.

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BME 314 Lecture 7 - DrugDeliveryII Krish Roy Ph.D Associate Professor Dept of Biomedical Engineering Controlledrelease:Basickinetics Rate of drug

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