Copyright by Wei Yang 2009 The Dissertation Committee for Wei Yang Certifies that this is the approved version of the following dissertation: Improvement in the Bioavailability of Poorly Water-Soluble Drugs via Pulmonary Delivery of Nanoparticles Committee: Robert O. Williams III, Supervisor Keith P. Johnston, Co-Supervisor James W. McGinity Jason T. McConville Nathan P. Wiederhold Improvement in the Bioavailability of Poorly Water-Soluble Drugs via Pulmonary Delivery of Nanoparticles by Wei Yang, B.S.; M.S.Phr. Dissertation Presented to the Faculty of the Graduate School of The University of Texas at Austin in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy The University of Texas at Austin August 2009 Dedication To my loving and ever-supportive father and mother, Mr. Jingsen Yang and Mrs. Fengqing Wang Acknowledgements I would foremost like to extend my deepest gratitude to my supervising advisor, Dr. Robert O. Williams III, for providing me the opportunities over the past four years. His insightful guidance, positive attitude, and endless encouragement throughout my entire study lead me to where I am today. I would also like to thank my co-supervisor, Dr. Keith P. Johnston, for his constructive suggestions, experimental ideas, and meticulous guidance to improve my ability to communicate and write scientific papers. I sincerely appreciated the mentorship I received from Dr. James W. McGinity. His extensive and solid knowledge base, his life lessons, his enthusiasm for being a pharmaceutical scientist, and his care of students influence me immensely and will be beneficial to my career and development throughout my life. In addition, I would like to thank Dr. Jason T. McConville for his mentorship during my early years in graduate school, constant encouragement, and willingness to help whenever I have questions. I would also like to express my thankfulness to Dr. Nathan P. Wiederhold for his invaluable help in designing and conducting in vivo studies on inhaled itraconazole, insight into analysis of itraconazole delivery and pharmacokinetics, and guidance to improve my communication ability. I am very thankful to the College of Pharmacy Staff for making my busy life easier: Ms. Yolanda Abasta, Ms. Mickie Sheppard, Ms. Claudia McClelland, Ms. Joyce McClendon, Ms. Janet Larsen, Mr. Jay Hamman, and Mr. Jim Baker. v I would also like to thank all of the past and present post doctoral fellows, graduate students for their friendship, assistance, and guidance. Specifically, I thank Dr. Jiahui Hu, Dr. Jason McConville, Ms. Jasmine Tam, Dr. Keat Theng Chow, Mr. Bo Long, Dr. Dave Miller, Dr. Jim DiNunzio, Dr. Kirk Overhoff, Dr. Troy Purvis, Dr. Michal Mateucci, Dr. Josh Engstrom, Dr. Shawn Kucera, Dr. Justin Tolman, Mr. Alan Watts, Mr. Kevin O’Donnell, Ms. Piyanuch Wonganan, Ms. Yoen Ju Son, Ms. Sandra Schilling, Ms. Nicole Nelson, Ms. Stephanie Bosselmann, Dr. Caroline Dietzsch, Dr. Dorothea Sauer, Ms. Loni Coots, and many others. Finally, and most importantly, I express my deepest love and appreciation to my parents, Mr. Jingsen Yang and Mrs. Fengqing Wang for their unconditional love and support throughout every stage of my life. I would also like to thank my brother and all other family members for their love, care and encouragement. Lastly, I would like to extend my gratitude to my best friend Ms. Yubin Wu, my roommates Dr. Xuan Huang and Ms. Qian Wang for their friendship, care and support, which helped me went through hard times when I would need a helping hand most and without my family around. vi Improvement of Bioavailability of Poorly Water-Soluble Drug via Pulmonary Delivery of Nanoparticles Publication No._____________ Wei Yang, Ph.D. The University of Texas at Austin, 2009 Supervisors: Robert O. Williams III and Keith P. Johnston High throughput screening techniques that are routinely used in modern drug discovery processes result in a higher prevalence of poorly water-soluble drugs. Such drugs often have poor bioavailability issues due to their poor dissolution and/or permeability to achieve sufficient and consistent systemic exposure, resulting in sub- optimal therapeutic efficacies, particularly via oral administration. Alternative formulations and delivery routes are demanded to improve their bioavailability. Nanoparticulate formulations of poorly water-soluble drugs offer improved dissolution profiles. The physiology of the lung makes it an ideal target for non-invasive local and systemic drug delivery for poorly water-soluble drugs. In Chapter 2, a particle engineering process ultra-rapid freezing (URF) was utilized to produce nanostructured aggregates of itraconazole (ITZ), a BCS class II drug, vii for pulmonary delivery with approved biocompatible excipients. The obtained formulation, ITZ:mannitol:lecithin (1:0.5:0.2, w/w), i.e. URF-ITZ, was a solid solution with high surface area and ability to achieve high magnitude of supersaturation. An aqueous colloidal dispersion of URF-ITZ was suitable for nebulization, which demonstrated optimal aerodynamic properties for deep lung delivery and high lung and systemic ITZ levels when inhaled by mice. The significantly improved systemic bioavailability of inhaled URF-ITZ was mainly ascribed to the amorphous morphology that raised the drug solubility. The effect of supersaturation of amorphous URF-ITZ relative to nanocrystalline ITZ on bioavailability following inhalation was evaluated in Chapter 3. The nanoparticulate amorphous ITZ composition resulted in a significantly higher systemic bioavailability than for the nanocrystalline ITZ composition, as a result of the higher supersaturation that increased the permeation. In Chapter 4, pharmacokinetics of inhaled nebulized aerosols of solubilized ITZ in solution versus nanoparticulate URF-ITZ colloidal dispersion were investigated, under the hypothesis that solubilized ITZ can be absorbed faster through mucosal membrane than the nanoparticulate ITZ. Despite similar ITZ lung deposition, the inhaled solubilized ITZ demonstrated significantly faster systemic absorption across lung epithelium relative to nanoparticulate ITZ in mice, due in part to the elimination of the phase-to-phase transition of nanoparticulate ITZ. viii Table of Contents List of Tables .............................................................................................. xiv List of Figures...............................................................................................xv Chapter 1: Inhaled Nanoparticles – A Current Review ..................................1 1.1 Abstract.....................................................................................................1 1.2 Overview of Nanomaterials ......................................................................1 1.3 Characteristics of nanomaterials...............................................................2 1.4 The lungs as a delivery target for nanomaterials ......................................4 1.5 Deposition of nanomaterials in the respiratory tract.................................5 1.6 The fate of inhaled nanomaterials in the lung...........................................7 1.7 Systemic translocation of inhaled nanomaterials....................................11 1.8 Factors influencing the fate of nanomaterials.........................................14 1.9 Potential applications of nanomaterials in drug delivery........................16 1.10 Delivery devices....................................................................................18 1.11 Pulmonary delivery of therapeutic nanomaterials ................................20 1.12 Conclusions...........................................................................................23 1.13 References.............................................................................................24 1.14 Dissertation objectives and outline .......................................................33 Chapter 2: High Bioavailability from Nebulized Itraconazole Nanoparticle Dispersions with Biocompatible Stabilizers ........................................40 2.1 Abstract...................................................................................................40 2.2 Introduction.............................................................................................40 2.3 Materials and Methods............................................................................44 2.3.1 Materials ..............................................................................................44 2.3.2 Preparation of nanostructured aggregate powder of ITZ using URF technology............................................................................................44 2.3.3 Preparation of physical mixture...........................................................45 2.3.4 Powder X-Ray Diffraction (XRD).......................................................45 2.3.5 Scanning Electron Microscopy (SEM) ................................................45 2.3.6 Scanning Transmission Electron Microscopy (STEM) .......................46 ix 2.3.7 Thermal Analysis.................................................................................46 2.3.8 True Density Measurements ................................................................47 2.3.9 Particle Size Analysis by Laser Diffraction.........................................47 2.3.10 Brunauer-Emmett-Teller (BET) Specific Surface Area Analysis .....48 2.3.11 Dissolution Testing at Supersaturation Conditions ...........................48 2.3.12 In Vitro