BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 o poly(ortho esters)(SKIP?) ooO RO H-O Ho、OH Medically-applied polymers are chosen for metabolizable or excretable final degradation products HO -(CH-C-O-CH-C-O-x(CH2-C-0-CH2-C-O)y HO-CH-C-OH HO-C Kreb@ cycle CO2+ H2O Kreb's cycle citric acid cycle (conversion of pyruvate from glycolytic cycle into energy) (D H. Lewis in"Biodegradable polymers as drug delivery systems, 1990 p. 1-41 M. Chasin, ed PCL H2o Citric acid cycle -(CH2)5-C-O-) HO-((CH2)5-C-OH Co2 +H2o 6-hydroxycaproic acid polyhydroxybutyrate: ( C-O-CH(CH3)CH2h、o HO-CH(CH3)-CH2 -C-OH D-3-hydroxybutyrate (normal blood constituent Holmes, Phys. Technol. 16, 32(1985) · What doesnt work? o e.g. poly(ethylene terephthalate)(PET)-used for soda bottles breaks down to aromatic oligomers which form deposits in body therefore more than just a hydrolysis-susceptible bond is needed CRYSTALLINE, T INELASTIC 256·T.67 Lecture 1-IntroductionBEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 o poly(ortho esters) (SKIP?) H2O RÕ n O RÕ O O + O O O RÕ O R HO HO OH OH RÕ O R Medically-applied polymers are chosen for metabolizable or excretable final degradation products: PLGA: CH3 O CH3O O O H2O CH3 O O -(CH-C-O-CH-C-O-)x-(CH2-C-O-CH2-C-O)y- HO-CH-C-OH + HO-CH2-C-OH KrebÕs cycle CO2 + H2O Kreb’s cycle = citric acid cycle (conversion of pyruvate from glycolytic cycle into energy) (D.H. Lewis in “Biodegradable polymers as drug delivery systems,” 1990 p. 1-41 M. Chasin, ed.) PCL: O H2O O Citric acid cycle -((CH2)5-C-O-)n- HO-((CH2)5-C-OH CO2 + H2O 6-hydroxycaproic acid poly(hydroxybutyrate): O H2O O -(-C-O-CH(CH3)-CH2-)n- HO-CH(CH3)-CH2-C-OH D-3-hydroxybutyrate (normal blood constituent) Holmes, Phys. Technol. 16, 32 (1985) • What doesn’t work? o e.g. poly(ethylene terephthalate) (PET) – used for soda bottles ƒ breaks down to aromatic oligomers which form deposits in body ƒ therefore more than just a hydrolysis-susceptible bond is needed! = = = = Lecture 1 – Introduction