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B IOMATERIALS L AB Drug Delivery & Controlled Release. Monday, March 19 th and Tuesday, March 20 th. BME 245/445 – Lab 4. P RE-LAB. Sign-in Quiz (Lin. 2009). BME 245/445 – Lab 4. Big Picture: Drug Delivery. Toxic Level. With Delivery Device. Period of Efficacy. Drug Concentration.
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BIOMATERIALS LABDrug Delivery & Controlled Release Monday, March 19th and Tuesday, March 20th BME 245/445 – Lab 4
PRE-LAB • Sign-in • Quiz (Lin. 2009) BME 245/445 – Lab 4
Big Picture: Drug Delivery Toxic Level With Delivery Device Period of Efficacy Drug Concentration • Control drug delivery rate, dose & location Traditional Delivery Time Therapeutic Range BME 245/445 – Lab 4
Big Picture: Drug Delivery • Monolithic Device • Drug is released by diffusion out of polymer matrix • Release rate depends on: • Drug loading • Drug size • Mesh size • Shape of device • Applied in Norplant – implantable contraceptive device • Release hormone over 5 years • Discontinued – unpopular, not cost-effective http://www.sigmaaldrich.com/materials-science/biomaterials/tutorial.html BME 245/445 – Lab 4
LINEAR MOLECULES • PEGMA (2, 10, 20kD) • Increase number of repeat units (n) • Alter mesh size and thus rate of BSA release Large Mesh Size Small Mesh Size BME 245/445 – Lab 4
METHACRYLATE POLYMERIZATION Step-growth Polymerization 1 “Arm” MA PEG (Lin, C.C., Pharmaceutical Research. 26(3): 631-643. 2009) BME 245/445 – Lab 4
SECTION 1 PEGMA Network Synthesis • 10wt% PEGDA in PBS+BSA(10 mg/mL) • 10% photo-initiator by volume (LAP) • 40μL placed in 1mL syringe (tip cut off) • to create cylindrical hydrogel sample geometry • exposed to UV-lamp for 10min • Remove and place in PBS
SECTION 2 Protein Collection Time Course (done by TA) • BSA in hydrogel will release into surrounding PBS • PBS will be routinely changed (stored in -80°C freezer) • BSA concentration will be assessed for total release BME 245/445 – Lab 4
SECTION 3 Protein Detection Assay – Coomassie • Compared unknowns to known [BSA] standards • Measure Absorbance at 590nm BME 245/445 – Lab 4
From plate reader…. BME 245/445 – Lab 4
What we are interested in…. % BSA released Time BME 245/445 – Lab 4
Theoretical Governing Eqns Drug diffuses out z=L z=L/2 z=0 Drug diffuses out BME 245/445 – Lab 4
Governing Eqns time C0 Drug Concentration CA 0 z=L z=0 BME 245/445 – Lab 4
Simplifying Governing Eqns BME 245/445 – Lab 4
Mesh Size Calculations BME 245/445 – Lab 4
Safety • General • PEG/PBS/BSA are relatively benign • Lab glasses, gloves, closed toed shoes • No food, no drinks, no applying makeup
LAB TEAMS- Monday BME 245/445 – Lab 4
LAB TEAMS- Tuesday BME 245/445 – Lab 4