DEVELOPMENT OF A NOVEL BIODEGRADABLE DRUG POLYMER FOR THE MODIFICATION OF INFLAMMATORY RESPONSE by Sara Khor A thesis submitted in conformity with the requirements for the degree of MASTER OF APPLIED SCIENCE Graduate Department of Institute of Biomaterials and Biomedical Engineering University of Toronto © Copyright by Sara Khor (2008) DEVELOPMENT OF A NOVEL BIODEGRADABLE DRUG POLYMER FOR THE MODIFICATION OF INFLAMMATORY RESPONSE MASTER OF APPLIED SCIENCE, 2008 Sara Khor Institute of Biomaterials and Biomedical Engineering University of Toronto ABSTRACT The first objective of this thesis was to assess the feasibility of designing a “smart” degradable polymer that can release anti-inflammatory drugs in response to inflammatory- related enzymes. The drug polymer was synthesized using diisocyanates, poly(caprolactone) diols, and oxaceprol (OC) biomonomers. Biodegradation studies demonstrated that the trimethylhexamethylene diisocyanate-based drug polymer responded to an inflammatory enzyme to release more OC, while a 1, 12-diisocyanatododecane analog demonstrated minimal drug release. The drug delivery response was believed to be a direct function of the molecular structure and distribution of the hard segment. The second objective of this thesis was to elucidate the anti-inflammatory mechanisms of OC by investigating its effects on cytokine-induced monocytic-cells adhesion in human umbilical vein endothelial cells (HUVECs) in vitro. Results showed that OC had no direct effect on the monocyte-endothelium adhesion, suggesting that OC may mediate inflammation by mechanisms other than those suggested by the literature. ii ACKNOWLEDGEMENTS First and foremost, Professor Paul Santerre, your guidance, support and unfailing patience throughout the highs and lows of this thesis and the preparation of this document have made this thesis possible. I would not have been able to pull through many difficult times without your organized leadership and optimism. To Dr. Frank LaRonde: it has been an honor working with you on this project. Your quality as a scientist has been inspirational, and your friendship and advice (anytime, anywhere) have made these two years truly memorable and enjoyable. I would also like to thank my Masters committee for their constructive criticisms throughout this thesis. This project would not have been possible without the assistance of many individuals. Many thanks to the Interface Biologics team for your wonderful support throughout this project. Thanks to Dr. Fan Gu, Dr. Peng Chen for your help with synthesis and chemical analysis, as well as the warm support. To Dr. David Courtman and Dr. Effat Rezaei: you made cell work so fun and feasible. Thank you so much for your guidance with all the HUVEC work. I am also grateful to Mr. Frank Gibbs for his help in DSC studies; Dr Jian Wang for his assistance in SEM analysis and Dr Alex Young for Mass Spectrometry analysis. Many thanks to Dr. Santerre lab team: Meilin, for your extensive knowledge in chemistry and your lovely surprises to keep me positive; Kuihua, for all the help and care, without you nothing would be possible; Hung, Patrick, JP, Ekanki, Soroor, Yi and many others whose friendships and support made these two years a lovely experience. And thank you, my dearest friends, Ellwood, Jean, Darrell, Onil, James, Cheri, Daniel and many others, for reminding me that life is so wondrously beautiful; and my dear family, for loving, believing and supporting me unconditionally since the very first day. iii TABLE OF CONTENTS ABSTRACT ........................................................................................................................... II ACKNOWLEDGEMENTS .................................................................................................III TABLE OF CONTENTS .....................................................................................................IV LIST OF FIGURES...........................................................................................................VIII LIST OF TABLES...............................................................................................................XV CHAPTER 1 INTRODUCTION........................................................................................... 1 1.1 BACKGROUND.................................................................................................................. 1 1.2 HYPOTHESIS..................................................................................................................... 2 1.3 THESIS OUTLINE .............................................................................................................. 3 REFERENCE .......................................................................................................................4 CHAPTER 2 LITERATURE REVIEW............................................................................... 5 2.1 POLYURETHANE CHEMISTRY, SYNTHESIS AND CHARACTERISTICS.................................. 5 2.1.1 Polyurethane Chemistry .......................................................................................... 5 2.1.2 The synthesis of polyurethane.................................................................................. 7 2.1.3 Polyurethane Degradation ...................................................................................... 9 2.2 POLYMERIC DRUG DELIVERY ........................................................................................ 12 2.2.1 Controlled Drug Delivery...................................................................................... 12 2.3 POLYMER-BASED DRUG DELIVERY SYSTEMS.................................................................. 13 2.3.1 Diffusion-based systems......................................................................................... 15 2.3.2 Water penetration-based systems .......................................................................... 18 2.3.3 Polymeric drug conjugates.................................................................................... 20 2.3.4 Responsive delivery systems .................................................................................. 23 2.4 MEDICAL DEVICE RELATED INFLAMMATION AND INFLAMMATORY DISEASES.............. 25 2.4.1 Inflammation Responses and Repair ..................................................................... 26 2.4.2 Biomaterials, Tissue Engineering and Regeneration ............................................ 28 2.4.3 Inflammatory Diseases .......................................................................................... 29 2.4.4 Anti-inflammatory Medications............................................................................. 30 REFERENCE ..................................................................................................................... 33 CHAPTER 3 SYNTHESIS AND CHARACTERIZATION OF A NOVEL ANTI- iv INFLAMMATORY DRUG POLYMER USING OXACEPROL ................................... 43 ABSTRACT ........................................................................................................................... 43 INTRODUCTION .................................................................................................................... 44 3.2 MATERIALS AND METHODS ........................................................................................... 48 3.2.1 Drug Biomonomer Synthesis ................................................................................. 48 3.2.2 Drug Polymer Synthesis ........................................................................................ 52 3.2.3 Characterization of Biomonomer and Polymer..................................................... 53 3.2.4 Biodegradation studies .......................................................................................... 56 3.2.5 High Performance Liquid Chromatography ......................................................... 58 3.2.6 Scanning electron microscopy (SEM) ................................................................... 60 3.2.7 Statistical Analysis................................................................................................. 60 3.3 RESULTS ........................................................................................................................ 60 3.3.1 Biomonomer synthesis and characterization......................................................... 60 3.3.2 Polymer synthesis and characterization................................................................ 64 3.3.3 Degradation Profile and Degradation Products................................................... 68 3.3.5 SEM .......................................................................................................................74 3.4 DISCUSSION ................................................................................................................... 76 3.5 CONCLUSION.................................................................................................................. 86 3.6 ACKNOWLEDGEMENTS................................................................................................... 87 REFERENCE ..................................................................................................................... 88 CHAPTER 4 INTERACTION OF OXACEPROL ON TNF-ALPHA-INDUCED U937 MONOCYTE ADHESION ON HUMAN UMBILICAL VASCULAR ENDOTHELIAL CELLS ................................................................................................................................... 93 ABSTRACT