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Introduction/Materials & Methods (Kinetic Studies) PowerPoint Presentation
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Introduction/Materials & Methods (Kinetic Studies)

Introduction/Materials & Methods (Kinetic Studies)

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Introduction/Materials & Methods (Kinetic Studies)

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  1. Introduction/Materials & Methods (Kinetic Studies) By: Kristin Ackermann Amanda Rohs Blanca Skelding

  2. Introduction • Biocompatible polymers permit the controlled release of macromolecules • EVAc Polymer systems have a wide variety of applications • Chemotactic and growth factor release systems • Informational macromolecules • Delivery systems for insulin, interferon and antigens

  3. Introduction • Mechanism for macromolecular release has not been explained • Polymers capable of releasing molecules larger than their permeability limit • Incorporating macromolecules into a non-porous matrix results in the formation of an interconnected pore network • Diffusion of molecules through network provides basis for controlled release

  4. Method • BSA, β-lactoglobulin A and lysozyme powders sieved into specific size ranges • Dispersed in a 10% ethylene-vinyl acetate solution • Suspensions cast in flat glass mold at -80 C • Sheets dried in two 48-hour stages (-20 C and under vaccum at 20 C)

  5. Method • To test kinetics, 9 slabs were prepared: • Dimensions: 1cm x 1cm x 1mm • Coated on 5 faces using paraffin • One 1cm x 1cm face exposed (allowing for diffusion on only one face) • Stainless steel autoclips were pressed into the paraffin for anchors when placed in release medium

  6. Method • Release medium • Composed of 0.9% NaCl solution • Placed in 10mL amounts in 20mL vials • Slabs removed at specified time points • Slabs placed in vials containing fresh saline • Old solutions were spectrophotometrically analyzed for protein content

  7. Method • Protein particle densities determined using pycnometer with methylene chloride as solvent • Porosity was determined before and after release. • Before: dividing protein concentration in slab by protein particle density • After: liquid leaching of salicylate

  8. Method • In general, porosity values before and after release agreed to within 5% • Thickness of polymer slabs was also measured using a micrometer • Standard deviation for thickness measurements was less than 4% for each slab