ABC運輸蛋白的過度表達是多重抗藥性（MDR）的重要機制之一，癌細胞會同時對結構上無關的抗癌藥物產生抗藥性。避免癌細胞的多重抗藥性有不同方法，其中用聚合物納米載體來攜帶易受多重抗藥性影響的抗癌藥物近年來獲得了很大的關注。本研究的目標在使用一個相對新穎的納米開發技術，被稱為瞬時納米沉澱（FNP），去開發一種運載著易受多重抗藥性影響的抗癌藥物的聚合物納米粒子系統。為此，我們使用專門設計的四流多進旋渦混合器（MIVM），把阿黴素（DOX），一種屬於蒽環類的抗癌藥物，亦同時作為P糖蛋白（P-gp）底物的藥物，包進在二嵌段共聚物內。 / 目的：本研究的目的是:（一）通過MIVM，利用瞬時納米沉澱去配製運載DOX的聚合物納米粒子；（二）辨别和優化納米粒子的大小，物理性能和運載DOX聚合物納米粒子的體外釋放速率；（三）檢查納米粒子的表面元素和化學組成;(四）評估優化納米粒子在抗藥性癌症細胞模型的抗腫瘤能力和抵抗多重抗藥性的能力。 / 方法：不同藥物（DOX)對聚合物比例的瞬時納米沉澱是通過在四流MIVM中混合溶在有機溶液二甲基甲酰胺（DMF)或二甲基酮（ACT)的鹽酸阿黴素(DOX.HC1)或阿黴素游離鹼（DOX.FB)和兩親性二嵌段共聚物[聚乙二醇-聚乳酸；分子量2000-10000]和反抗溶劑（含有氫氧化鈉為DOX.HCl或純淨水DOX+FB)來製備的。納米混懸劑的平均粒徑和粒度分佈會通過動態光散射粒度分析法去檢測，表面電荷會通過界達電位測量去檢測。阿黴素的包封率和載藥量會用紫外/可見光譜儀在波長為480 nm時測定。粒子形態將會用原子力顯微鏡（AFM)來去檢測，粒子表面的組合物將會用X-射線光電子能譜（XPS)來去檢測DOX聚合物納米粒子在不同pH值的的體外釋放會通過紫外/可見光譜儀去檢測。DOX聚合物納米粒子的體外細胞毒性會利用橫若丹明B比色法檢定，藥物積累和反轉運會利用流式細胞儀分析來測定。 / 結果：在適當優化鹽酸阿黴素（DOX.HC1)或阿黴素游離鹼（DOX.FB)的聚合物的比例後，我們成功製備了平均粒徑小於100 nm的DOX聚合物納米粒子(DOX.NP)與使用在有機溶液中DOX.HC1和水相的氫氧化鈉中和法相比，通過在有機溶液中的DOX.FB和純水作為反溶劑來製備的DOX.NP表現出類似的平均粒子大小（小於100 nm)，但顯示出更高的藥物包封率（48 %， 而不是中和法的25 %)。用DOX.FB製備的DOX.NP的載藥量可達14 %DOX.NP表現出pH依賴性的藥物釋放曲線，和在酸性pH值時更强的累積釋放率。X-射線光電子能譜顯示沒有阿黴素出現在納米粒子的表面上P-gp過度表達的LCC6抗藥性乳腺癌细胞的細胞毒性作用顯示了 DOX.NP和DOX.HC1在缓衝溶液中的差異並不顯著。相對DOX.HC1，流式細胞儀分析確定了 DOX.NP明顯增加了細胞攝取DOX的能力。此外，在外排後，DOX.NP在細胞內DOX的濃度顯示出了更長的保留時間。 / 結論：一種通過在多進旋過混合器（MIVM)進行反溶劑沉澱，用於配製具有可控的粒子大小運載DOX的聚合物納米粒子的快速，方便，和可重複性的方法已經被開發。配製的納米粒子顯示出pH值依賴性持續的藥物釋放曲線和更強的癌細胞攝取DOX能力。 / Over-expression of ATP-binding cassette (ABC) is one of the most important mechanisms responsible for multidrug resistance (MDR), in which tumor cells exhibit simultaneous resistance to structurally unrelated anticancer drugs. Various approaches have been attempted to circumvent MDR in cancer cells, among which polymeric nanocarrier for delivery of MDR-sensitive anticancer drugs has received considerable attention in recent years. The present project was aimed at developing a polymeric nanoparticle system using a relatively novel nanoparticle technology termed flash nanoprecipitation (FNP) for delivery of MDR-susceptible chemotherapeutic agents. To this end, doxorubicin (DOX), an anthracycline anticancer agent and a P-gp substrate, was incorporated into an amphiphilic diblock copolymer using a specially designed four-stream multi-inlet vortex mixer (MIVM). / PURPOSES: The objectives of the present study are: (a) to formulate DOX-loaded polymeric nanoparticles by FNP using an MIVM; (b) to characterize and optimize the particle size, physical properties and in vitro DOX release rate of the formulated nanoparticles; (c) to examine the surface elemental and chemical compositions of the formulated nanoparticles; (d) to evaluate the anti-tumor activity of the optimized nanoparticles and their ability to combat MDR in resistant cancer cell line models. / METHODS: FNP of DOX was effected in a four-stream MIVM by mixing organic solutions of doxorubicin hydrochloride (DOX.HCl) or doxorubicin free base (DOX.FB) and an amphiphilic diblock copolymer [polyethylene glycol-polylactic acid (PEG-PLA); MW2k-10 ki]n dimethylformamide (DMF) or acetone (ACT) at different drug-to-polymer ratios with an antisolvent (water containing sodium hydroxide for DOX.HCl or pure water for DOX.FB). The resulting nanosuspensions were characterized for mean particle size and size distribution by dynamic light scattering particle size analysis; surface charges by zeta potential measurements; drug encapsulation efficiency and drug loading by UV/visible spectroscopy at 480 nm; particle morphology by atomic force microscopy (AFM); and surface composition by x-ray photoelectron spectroscopy (XPS). In vitro DOX release from the nanoparticles was measured at different pHs by UV/visible spectroscopy. In vitro cytotoxicity was evaluated by Sulforhodamine B colorimetric assay, and drug accumulation and efflux were determined by flow cytometric analysis. / RESULTS: DOX-loaded polymeric nanoparticles (DOX.NP) with mean particle size below 100 nm were obtained after appropriate optimization of the DOX.HCl or DOX.FB to polymer ratio. Compared with the neutralization method using DOX.HCl in the organic phase and sodium hydroxide in the aqueous phase, DOX.NP prepared with DOX.FB in the organic phase and pure water as antisolvent exhibited a similar mean particle size (< 100 nm) but a significantly higher drug encapsulation efficiency (48% as opposed to 25% for the neutralization method). Drug loading of DOX.NP prepared with DOX.FB could reach up to 14%. DOX.NP exhibited a pH-dependent drug release profile with a much higher cumulative release rate at acidic pHs. XPS revealed that no DOX was present on the nanoparticle surface. The cytotoxic effect on P-gp over-expressing LCC6/MDR cell line revealed insignificant differences between DOX.NP and DOX.HCl in buffered aqueous media. DOX.NP exhibited a marked increase in DOX cellular uptake relative to free DOX, as determined by flow cytometric analysis. Furthermore, DOX.NP showed a significant retention of intracellular concentration of DOX after efflux. / CONCLUSION: A rapid, convenient, and reproducible method for generating DOX-loaded polymeric nanoparticles with controllable particle size through antisolvent precipitation in a multi-inlet vortex mixer has been developed. The formulated nanoparticles displayed a pH-dependent sustained drug release profile and an enhanced DOX uptake into cancer cells. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Tam, Yu Tong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 119-130). / Abstracts also in Chinese. / ABSTRACT --- p.i / 摘要 --- p.iv / ACKNOWLEDGEMENTS --- p.vi / TABLE OF CONTENTS --- p.vii / LIST OF FIGURES --- p.x / LIST OF TABLES --- p.xiii / ABBREVIATIONS --- p.xv / Chapter CHAPTER 1. --- Introduction --- p.1 / Chapter 1.1 --- Rationale of the Study --- p.2 / Chapter 1.2 --- Doxorubicin --- p.3 / Chapter 1.2.1 --- Origin --- p.3 / Chapter 1.2.2 --- Physico-chemical properties --- p.6 / Chapter 1.2.3 --- Mechanism of Action --- p.7 / Chapter 1.2.4 --- Multidrug Resistance in Cancer --- p.7 / Chapter 1.2.4.1 --- Mechanisms of Multidrug Resistance --- p.8 / Chapter 1.3 --- Nanoparticles for Cancer Therapy --- p.9 / Chapter 1.3.1 --- Properties of Nanoparticles --- p.9 / Chapter 1.3.1.1 --- Small Particle Size --- p.10 / Chapter 1.3.1.2 --- High Payload Density --- p.11 / Chapter 1.3.1.3 --- Flexible Modification of Surface Properties --- p.11 / Chapter 1.3.2 --- Targeted Cancer Therapy --- p.12 / Chapter 1.3.2.1 --- Passive Tumor Targeting --- p.13 / Chapter 1.3.2.2 --- Active Tumor Targeting --- p.14 / Chapter 1.3.3 --- Reversal of Multidrug Resistance --- p.15 / Chapter 1.3.3.1 --- Endocytosis of Nanoparticles --- p.16 / Chapter 1.3.4 --- Nanoparticle Approaches to Anti-cancer Drug Delivery --- p.17 / Chapter 1.3.4.1 --- Liposomes --- p.18 / Chapter 1.3.4.2 --- Polymeric Nanoparticles --- p.18 / Chapter 1.4 --- Fabrication of Nanoparticles --- p.19 / Chapter 1.5 --- Aims and Scope of the Present Study --- p.21 / Chapter CHAPTER 2. --- Materials & Methods --- p.23 / Chapter 2.1 --- Materials --- p.24 / Chapter 2.1.1 --- Chemicals --- p.24 / Chapter 2.1.2 --- Materials for Cell Culture --- p.25 / Chapter 2.2 --- Methods --- p.26 / Chapter 2.2.1 --- Preparation of Doxorubicin Nanoparticles by Flash Nanoprecipitation --- p.26 / Chapter 2.2.1.1 --- Acid-Base Neutralization during Mixing --- p.26 / Chapter 2.2.1.2 --- Preparation of Doxorubicin Free Base before Mixing --- p.29 / Chapter 2.2.1.2.1 --- Doxorubicin Free Base Preparation --- p.29 / Chapter 2.2.2 --- Determination of Particle Size and Zeta Potential --- p.30 / Chapter 2.2.3 --- Co-stabilizers and Particle Stability --- p.30 / Chapter 2.2.4 --- Chemical Stability of Doxorubicin --- p.31 / Chapter 2.2.5 --- Determination of Encapsulation Efficiency --- p.31 / Chapter 2.2.5.1 --- Calibration Curve of Doxorubicin --- p.33 / Chapter 2.2.5.2 --- Dialysis --- p.33 / Chapter 2.2.5.3 --- Ultrafiltration --- p.35 / Chapter 2.2.6 --- Determination of Drug Loading --- p.35 / Chapter 2.2.6.1 --- Freeze Drying --- p.36 / Chapter 2.2.7 --- Morphological Examination --- p.36 / Chapter 2.2.7.1 --- X-ray Photoelectron Spectroscopy --- p.36 / Chapter 2.2.7.2 --- Atomic Force Microscopy --- p.36 / Chapter 2.2.8 --- In vitro release study --- p.37 / Chapter 2.2.8.1 --- Experimental Protocols --- p.37 / Chapter 2.2.8.2 --- Calculation of Cumulative Drug Release --- p.37 / Chapter 2.2.9 --- In vitro cytotoxicity study --- p.38 / Chapter 2.2.9.1 --- Sulforhodamine B Colorimetric Assay --- p.38 / Chapter 2.2.10 --- Cellular Uptake study --- p.39 / Chapter 2.2.10.1 --- Drug Accumulation Assay --- p.39 / Chapter 2.2.10.1 --- Drug Efflux Assay --- p.39 / Chapter 2.2.11 --- Analytical techniques --- p.40 / Chapter 2.2.11.1 --- UV/Vis Analysis --- p.40 / Chapter 2.2.11.2 --- HPLC Analysis --- p.40 / Chapter 2.2.12 --- Statistical analysis --- p.41 / Chapter CHAPTER 3. --- Results & Discussions --- p.42 / Chapter 3.1 --- Preparation of Doxorubicin Nanoparticles by Flash Nanoprecipitation --- p.43 / Chapter 3.1.1 --- Acid-Base Neutralization during Mixing --- p.44 / Chapter 3.1.1.1 --- Influence of Drug Concentration --- p.44 / Chapter 3.1.1.2 --- Influence of Alkaline Medium --- p.48 / Chapter 3.1.1.3 --- Influence of Drug-to-Polymer Ratios --- p.53 / Chapter 3.1.1.4 --- Particle Stability --- p.54 / Chapter 3.1.1.5 --- Co-stabilizers Tests on Stability --- p.55 / Chapter 3.1.1.5.1 --- Effect of PEG-PLA Co-polymers --- p.55 / Chapter 3.1.1.5.2 --- Effect of Co-stabilizers --- p.56 / Chapter 3.1.2 --- Preparation of Doxorubicin Free Base before Mixing --- p.62 / Chapter 3.1.2.1 --- Influence of Solvent System --- p.62 / Chapter 3.1.2.2 --- Influence of Drug-to-Polymer Ratios --- p.65 / Chapter 3.1.2.3 --- Drug Loading --- p.65 / Chapter 3.1.2.4 --- Particle Stability --- p.68 / Chapter 3.1.2.4.1 --- Concentrated Particle Stability --- p.73 / Chapter 3.2 --- Stability Studies on Doxorubicin Nanoparticle at Physiological and Cancer Cell pHs --- p.75 / Chapter 3.2.1 --- Chemical Stability --- p.75 / Chapter 3.2.2 --- Physical Stability --- p.77 / Chapter 3.3 --- In vitro Release Study --- p.79 / Chapter 3.4 --- Morphological Examination --- p.86 / Chapter 3.4.1 --- Zeta Potential --- p.92 / Chapter 3.5 --- In vitro Cellular Study --- p.93 / Chapter 3.5.1 --- Cellular Uptake Study --- p.93 / Chapter 3.5.1.1 --- Drug Accumulation and Drug Efflux --- p.93 / Chapter 3.5.2 --- Cytotoxicity of Blank Nanoparticles --- p.98 / Chapter 3.5.3 --- Cytotoxicity of DOX loaded Nanoparticles --- p.100 / Chapter CHAPTER 4. --- Conclusions --- p.106 / APPENDIX --- p.109 / REFERENCES --- p.118

Lee, Siu Fung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 89-91). / Abstracts in English and Chinese. / Content --- p.i / Acknowledgments --- p.iv / Abstract --- p.V / Abbreviations and Acronyms --- p.vii / Publications Originated from the Work of this Thesis --- p.ix / Chapter Chapter 1- --- Introduction / Chapter 1.1 --- Nanoparticle-based drug delivery --- p.1 / Chapter 1.2 --- Magnetic nanoparticle --- p.5 / Chapter 1.3 --- Iron oxide nanoparticle --- p.6 / Chapter 1.3.1 --- Coprecipitation --- p.7 / Chapter 1.3.2 --- Hydrothermal reaction --- p.7 / Chapter 1.3.3 --- Sol-gel reaction --- p.8 / Chapter 1.3.4 --- Solvothermal reaction --- p.8 / Chapter 1.3.5 --- Architecture of iron oxide nanoparticles as drug carriers --- p.9 / Chapter 1.4 --- Supramolecular chemistry involved in controlled release drug delivery system --- p.10 / Chapter 1.5 --- Nano valve --- p.15 / Chapter 1.6 --- Aim of project --- p.17 / Chapter Chapter 2- --- Stimuli-Responsive Drug Delivery Nanosystems based on Fe3O4@SiO2@crown ether Nanoparticles / Chapter 2.1 --- Background --- p.19 / Chapter 2.2 --- Synthesis of the dibenzo-crown ethers --- p.21 / Chapter 2.3 --- Synthetic method of functionalized nanoparticles --- p.22 / Chapter 2.4 --- Characterization of dibenzo-crown ethers --- p.25 / Chapter 2.4.1 --- Nuclear magnetic resonance (NMR) spectroscopy --- p.25 / Chapter 2.4.2 --- Mass spectrometry (MS) --- p.27 / Chapter 2.4.3 --- Infrared (IR) spectroscopy --- p.28 / Chapter 2.5 --- Characterization of nanoparticles --- p.29 / Chapter 2.5.1 --- Transmission electron microscopy (TEM) --- p.29 / Chapter 2.5.2 --- Energy-dispersive X-ray (EDX) spectroscopy --- p.34 / Chapter 2.5.3 --- IR spectroscopy --- p.39 / Chapter 2.5.4 --- Thermogravimetric analysis (TGA) --- p.41 / Chapter 2.5.5 --- Nitrogen absorption/desorption isotherms --- p.44 / Chapter 2.6 --- Biological study of functionalized nanoparticles --- p.45 / Chapter 2.6.1 --- Cytotoxicity study --- p.45 / Chapter 2.6.2 --- Cell adhesion study --- p.46 / Chapter 2.6.3 --- Cell proliferation study --- p.47 / Chapter 2.6.4 --- Cellular uptake of nanoparticles --- p.50 / Chapter 2.7 --- Drug loading under different stimuli --- p.54 / Chapter 2.8 --- Drug release profile of nanoparticles --- p.61 / Chapter 2.9 --- MRI study of nanoparticles --- p.67 / Chapter 2.10 --- Conclusion --- p.69 / Chapter Chapter 3- --- Experimental Procedures / Chapter 3.1 --- General Information --- p.72 / Chapter 3.2 --- General procedure of synthesis of polyethers 3a-b --- p.73 / Chapter 3.2.1 --- Synthesis of 3a --- p.74 / Chapter 3.2.2 --- Synthesis of 3b --- p.74 / Chapter 3.3 --- General procedure of synthesis of diesters 4a-b --- p.75 / Chapter 3.3.1 --- Synthesis of 4a --- p.75 / Chapter 3.3.2 --- Synthesis of 4b --- p.76 / Chapter 3.4 --- General procedure of synthesis of dibenzo crown ether esters 5a-c --- p.77 / Chapter 3.4.1 --- Synthesis of 5a --- p.77 / Chapter 3.4.2 --- Synthesis of 5b --- p.78 / Chapter 3.4.3 --- Synthesis of 5c --- p.78 / Chapter 3.5 --- General procedure of synthesis of dibenzo-crown ethers la-c --- p.79 / Chapter 3.5.1 --- Synthesis of la --- p.80 / Chapter 3.5.2 --- Synthesis of lb --- p.80 / Chapter 3.5.3 --- Synthesis of lc --- p.81 / Chapter 3.6 --- Preparation of superparamagnetic Fe3O4 nanoparticle with an average diameter 120 nm --- p.81 / Chapter 3.7 --- Preparation of core/shell Fe3O4@SiO2 nanoparticle --- p.82 / Chapter 3.8 --- Preparation of Fe3O4@SiO2@meso(CTAB)-Si02 nanoparticle --- p.82 / Chapter 3.9 --- Preparation of Fe3O4@SiO2@meso(CTAB)-SiO2-NH2 nanoparticle --- p.83 / Chapter 3.10 --- Preparation of Fe3O4@SiO2@meso-SiO2@crown ether(a-c) nanoparticles --- p.83 / Chapter 3.11 --- Protocol of biological study of functionalized nanoparticles --- p.84 / Chapter 3.11.1 --- MTT protocol --- p.84 / Chapter 3.11.2 --- Cytotoxicity study --- p.84 / Chapter 3.11.3 --- Cell adhesion study --- p.85 / Chapter 3.11.4 --- Cell proliferation study --- p.85 / Chapter 3.11.5 --- Cellular uptake of functionalized nanoparticles --- p.85 / Chapter 3.12 --- Drug loading of functionalized nanoparticles --- p.86 / Chapter 3.13 --- Drug release profile of functionalized nanoparticles --- p.87 / Chapter 3.14 --- MRI study of nanoparticles --- p.87 / References --- p.89 / Appendix / List of Spectra --- p.A-1

Introduction: Embolic agents are used to block blood flow of hypervascular tumours, ultimately resulting in target tissue necrosis. However, this therapy is limited by the formation of new blood vessels within the tumour, a process known as angiogenesis. Targeting angiogenesis led to the discovery of anti-angiogenic factors, large molecular weight proteins that can block the angiogenic process. The aim of this research is development of poly (vinyl alcohol) (PVA) aqueous solutions that cross-link in situ to form a hydrogel that functions as an embolic agent for delivery of macromolecular drugs. Methods: PVA (14 kDa, 83% hydrolysed), functionalised by 7 acrylamide groups per chain, was used to prepare 10, 15, and 20wt% non-degradable hydrogels, cured by UV or redox initiation. Structural properties were characterised and the release of FITCDextran (20kDa) was quantified. Degradable networks were then prepared by attaching to PVA (83% and 98 % hydrolysed) ester linkages with an acrylate end group. The effect on degradation profiles was assessed by varying parameters such as macromer concentration, cross-linking density, polymer backbone and curing method. To further enhance the technology, radiopaque degradable PVA was synthesised, and degradation profiles were determined. Cell growth inhibition of modified PVA and degradable products were also investigated. Results: Redox initiation resulted in non-degradable PVA networks of well-controlled structural properties. Increasing the solid content from 10 to 20wt% prolonged the release time from few hours to ~ 2 days but had no effect on the percent release, with only a maximum release of 65% achieved. Ester attachment to the PVA allowed flexibility in designing networks of variable swelling behaviors and degradation times allowing ease of tailoring for specific clinical requirements. Synthesis of radiopaque degradable PVA hydrogels was successful without affecting the polymer solubility in water or its ability to polymerize by redox. This suggested that this novel hydrogel is a potential liquid embolic with enhanced X-ray visibility. Degradable products had negligible cytotoxicity. Conclusion: Novel non-degradable and radiopaque degradable PVA hydrogels cured by redox initiation were developed in this research. The developed PVA hydrogels showed characteristics in vitro that are desirable for the in vivo application as release systems for anti-angiogenic factors.

The invasive nature and undesirable side-effects related to conventional cancer therapy, such as surgery and chemotherapy, have led to the development of novel drug delivery systems (DDS). A minimally invasive DDS using near-infrared (NIR) light as a trigger for drug release is investigated to reduce the adverse side-effects triggered by systemic delivery of chemotherapeutic drugs. The low tissue absorbance in the NIR region, λ = 650–2500 nm, allows the irradiation to penetrate through tissues to release cisplatin from a NIR-sensitive nanocomposite of Au-Au₂S. Our laboratory has recently shown that cisplatin can be effectively released from Au-Au₂S upon NIR irradiation. Cisplatin was loaded onto Au-Au₂S through its adsorption on COOH-functionalized alkanethiols coated on Au-Au₂S. The current work focuses on the development of methods to control the release of cisplatin. Drug release is controlled by either the irradiation parameters or the type of coatings. The effect of different coatings on NIR sensitivity and drug release is investigated. Molecular layers of HS-(CH₂)n-COOH and HS-CH₂-COO-CH₂(CH₂CH₂O)xCH₂-COOH have been successfully coated onto Au-Au₂S. The effect of different surface layers on drug adsorption is being examined. In addition, a mathematical model has been developed to describe the thermal effects of different irradiation parameters on soft tissues. / Singapore-MIT Alliance (SMA)

Glioblastoma multiforme (GBM) is the most common malignant central nervous system tumor. The ability of glioma cells to rapidly disperse and invade healthy brain tissue, coupled with their high resistance to chemotherapy and radiation have resulted in extremely poor prognoses among patients. In recent years, nitric oxide (NO) has been discovered to play a ubiquitous of role in human physiology and studies have shown that, at sufficient concentrations, NO is able to induce apoptosis as well as chemosensitization in tumor cells. This thesis discusses the synthesis and characterization of targeted NO donors for the treatment of GBM. Two glioma targeting biomolecules, Chlorotoxin (CTX) and VTWTPQAWFQWVGGGSKKKKK (VTW) were reacted with NO gas to synthesize NO donors. These NO donors, CTX-NO and VTW-NO, released NO for over 3 days and were able to induce cytotoxicity in a dose dependent manner in glioma cells. The biggest advantage, a result of the targeted delivery of NO, was that the NO donors did not have toxic effects on astrocytes and endothelial cells. To characterize the chemosensitizing effects of CTX-NO, cells were incubated with CTX-NO prior to exposure to temozolomide (TMZ) or carmustine (BCNU). These drugs are the most popular chemotherapeutics used in the treatment of GBM, but have only shown modest improvements in patient survival. Viability studies showed that CTX-NO selectively elicited chemosensitivity in glioma cells, whereas the chemosensitivty of astrocytes and endothelial cells remained unaffected. Further investigation showed that CTX-NO pretreatment decreased O6-methylguanine DNA methyltransferase (MGMT) and p53 levels, suggesting that a decrease in DNA repair ability may be the mechanism by which chemosensitivity is induced. Lastly, the effects of CTX-NO on glioma cell invasion and migration were studied using Boyden chamber and modified scratch assays. Non-toxic doses of CTX-NO decreased glioma cell invasion in a dose dependent manner. Studies quantifying matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) surface expression demonstrated that while MMP-2 expression was decreased by both CTX and CTX-NO, MMP-9 expression was decreased only by CTX-NO. Furthermore quantifying MMP-2 and MMP-9 activity levels showed that NO and CTX work synergistically to decrease the activity of the enzymes. These studies demonstrate that the decrease in glioma invasion resulting from CTX-NO treatment was partially a consequence of decreased levels of surface and activated MMP-2 and MMP-9. The work presented in this thesis describes a novel approach to treating GBM that can be modified to develop treatments for various other tumors. Furthermore this is the first study to develop glioma-targeting NO donors.

Microemulsions have gained interest from the pharmaceutical industry due to their ability to co-solubilize hydrophilic and lipophilic drugs, and to provide enhanced drug penetration. In this work, thermosensitive gelatin- and poloxamer 407-stabilized microemulsion-based gels (MBGs) were formulated using alcohol-free, low toxicity and low viscosity lecithin-based linker microemulsions. The addition of gelatin to water-rich bicontinuous microemulsions induced the formation of clear viscoelastic gels containing an oil-rich microemulsion as the gelatin seemed to dehydrate the original microemulsion. The addition of poloxamer 407 to water-continuous microemulsions produced MBGs with different gelation temperatures. High concentrations of lipophilic components in the microemulsion, particularly the oil, reduced sol-gel transition temperature, while hydrophilic components increased sol-gel transition temperature. Gelatin and poloxamer MBGs provided desirable viscoelastic properties for ophthalmic and transdermal applications with minimal impact on the transport properties of the original microemulsions.

Microemulsions have gained interest from the pharmaceutical industry due to their ability to co-solubilize hydrophilic and lipophilic drugs, and to provide enhanced drug penetration. In this work, thermosensitive gelatin- and poloxamer 407-stabilized microemulsion-based gels (MBGs) were formulated using alcohol-free, low toxicity and low viscosity lecithin-based linker microemulsions. The addition of gelatin to water-rich bicontinuous microemulsions induced the formation of clear viscoelastic gels containing an oil-rich microemulsion as the gelatin seemed to dehydrate the original microemulsion. The addition of poloxamer 407 to water-continuous microemulsions produced MBGs with different gelation temperatures. High concentrations of lipophilic components in the microemulsion, particularly the oil, reduced sol-gel transition temperature, while hydrophilic components increased sol-gel transition temperature. Gelatin and poloxamer MBGs provided desirable viscoelastic properties for ophthalmic and transdermal applications with minimal impact on the transport properties of the original microemulsions.

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Targeted intracellular delivery is a goal of many novel drug delivery systems to treat site-specific diseases thereby increasing the effectiveness of drugs and reducing side effects associated with current drug administration. The development of ultrasound-enhanced delivery is aimed at providing a targeted means to deliver drugs and genes intracellularly by utilizing ultrasound s ability to non-invasively focus energy into the body and generate cavitation, which has been found to cause transient poration of cells. To address some of the current issues in this field, the goals of this study were (i) to develop a measurement of cavitation to correlate with cellular bioeffects and (ii) to evaluate the ability of ultrasound to target delivery into cells in viable tissue. In addition, this study sought to exploit the shear-based mechanism of cavitation by (iii) developing a simplified device to expose cells to shear stress and cause intracellular uptake of molecules. This study has shown that broadband noise levels of frequency spectra processed from cavitation sound emissions can be used to quantify the kinetic activity of cavitation and provide a unifying parameter to correlate with the cellular bioeffects. We further demonstrated that ultrasound can target delivery of molecules into endothelial and smooth muscle cells in viable arterial tissue and determined approximate acoustic energies relevant to drug delivery applications. Lastly, we developed a novel device to expose cells to high-magnitude shear stress for short durations by using microfluidics and demonstrated the ability of this method to cause delivery of small and macromolecules into cells. In conclusion, this work has advanced the field of ultrasound-enhanced delivery in two major areas: (i) developing a real-time non-invasive measurement to correlate with intracellular uptake and viability that can be used as means to predict and control bioeffects in the lab and potentially the clinic and (ii) quantitatively evaluating the intracellular uptake into viable cells in tissue due to ultrasound that suggest applications to treat cardiovascular diseases and dysfunctions. Finally, by using shear forces generated in microchannels, we have fabricated a simple and inexpensive device to cause intracellular uptake of small and large molecules, which may have applications in biotechnology.

Traditional methods of drug delivery to the eye include topical application, intraocular injection and systemic administration; however, each method has its limitation to efficiently delivery drugs to the back of the eye. In this study, microneedles were tested to provide targeted drug delivery into the eye in a minimally invasive way. To better interpret subsequent microneedle studies, we first quantified lateral drug diffusion profile within the sclera, by carrying out a diffusion study of a model compound, sulforhodamine, through human cadaver sclera, and developing a theoretical model for prediction of drug delivery kinetics and distribution. The results showed that measurable amounts of sulforhodamine were detected at distances of 5 and 10 mm from the sulforhodamine donor reservoir at 4 h and 3 days, respectively. The effective lateral diffusivity of sulforhodamine was determined to be 3.82 x 10-6 cm2/s, which is similar in magnitude to the transverse diffusivity. We next assessed the capability of using coated solid metal microneedles to deliver drugs into the ocular tissue in both in vitro and in vivo scenarios. The in vitro insertion tests showed that these microneedles were mechanically strong enough to penetrate into human cadaver sclera, and the coating solution rapidly dissolved off the needles after insertion and had been deposited within the tissue. In the in vivo experiments, microneedle delivery exhibited elevated fluorescein levels in the rabbit eye 60 times greater than that delivered by topical application of the equivalent dose. Similarly, microneedle delivery of pilocarpine caused rapid and extensive pupil constriction. Safety exams reported no inflammatory responses in the eye after microneedle administrations. We also used hollow glass microneedles to infuse solutions into the sclera tissue in vitro and examined the physiological barriers for flow. On average, 18 microliters of sulforhodamine solution and a solution containing nanoparticles was delivered into the sclera upon retraction of the microneedle. Successful delivery of micron-sized particles into the sclera could be improved by breaking down tightly packed collagen and GAG fibers using either collagenase or hyaluronidase.