<p>  </p> <p>The development of a novel technique employing the use of a linear quadrupole ion trap mass spectrometer coupled to a Nd:YAG laser and a home-built fast reagent-mixing apparatus is detailed and used to detect the short-lived tetrahedral reaction intermediate of the reaction of acetyl chloride with ethanol in microdroplets. Additionally, tandem and high-resolution mass spectrometry is used to characterize potential precursors for solution-processed metal selenide semiconductors in order to determine a synthetic route to sulfur-free thin films. Lastly, Raman MCR (multivariate curve resolution) spectroscopy is used to study the binding-induced conformational change of 1-bromopropane upon binding to α-cyclodextrin as a model system to examine guest conformational changes upon binding to a host molecule.</p>

京都大学 / 新制・論文博士 / 博士(農学) / 乙第13567号 / 論農博第2913号 / 新制||農||1101(附属図書館) / (主査)教授 小川, 順, 教授 阪井, 康能, 教授 栗原, 達夫 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

The effects of taste masking are determined by interactions between drug and excipients as well as the microstructures of the particulate drug delivery systems (DDS). Cyclodextrin (CD) is a widely used taste masking agent, to which the relationship between kinetic parameters (Ka and Kd) of a drug and taste masking remains unexplored, which is investigated for the first time in this study. A data base of the kinetic parameters for drug-CD was established by Surface Plasmon Resonance Imaging (SPRi) and High Performance Affinity Chromatography (HPAC). Combined with the electronic tongue, Ka and Kd based models for the taste masking effect of HP-β-CD were successfully established and applied to the prediction of taste masking effects. Paracetamol was used as a model drug for taste masking formulation optimization. As well as drug release the microstructure of solid DDS has considerable influence on drug taste. The microstructure of lipid microspheres and the molecular distribution of drug and excipients in lipid microspheres were investigated by Synchrotron radiation-based micro-computed tomography (SR-μCT) and Synchrotron radiation-based Fourier-transform infrared spectromicroscopy (SR-FTIR), respectively. The results demonstrated that the polymeric formulation components as well as shape and particle size of the drug were the key factors to taste masking of paracetamol by inhibiting bust release thereby reducing the interaction intensity of the bitterness. The FTIR absorption spectra confirmed the deposition and formation of chitosan and gelatin films on the drug microsphere surface by layer-by-layer coating. In conclusion, this research demonstrates the molecular kinetic basis of CD taste-masking as well as microstructural basis of particle systems for bitter taste masking.

Active substances can be stabilized to be protected from undesirable reactions, aggregation, and leaking, which would keep the intended functions of the active substances without premature degradation. Among such active substances are paraffin-based organic phase change materials (PCMs) and essential oils (EOs), which feature attractive characteristics, e.g., high latent heat of fusion and inherent antimicrobial activity. However, their high volatility requires an effective stabilization strategy. Petroleum-based synthetic polymers have often been employed to stabilize PCMs and EOs by encapsulation and complexation pathways. Despite their proven effectiveness, these polymers are from non-renewable resources, and non-degradable and often toxic, which has prompted a need to develop a substitute arising from natural polymers that are environmentally benign, biodegradable, and sustainable. Valorization of biomass in this regard would add extra value to biomass otherwise burned or wasted. This dissertation will present the development of microcapsules and inclusion complexes consisting of a hydrophobic active substance core and a polysaccharidic shell originating from biomass. The first two chapters will explain the introduction and experimental details. Chapter 3 will present the microencapsulation of n-hexadecane as PCM via oil-in-water (O/W) Pickering emulsions stabilized by unmodified cellulose nanofibrils (CNFs) through a sonochemical technique. Chapter 4 will investigate the incorporation of the PCM-CNF microcapsules into TEMPO-oxidized CNF films for building application. Finally, Chapter 5 will show the synthesis of EOs-beta cyclodextrin (βCD) inclusion complexes as a guest-host system through a sonochemical technique.

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京都大学 / 新制・論文博士 / 博士(医学) / 乙第13481号 / 論医博第2256号 / 新制||医||1059(附属図書館) / (主査)教授 平井 豊博, 教授 岩田 想, 教授 秋山 芳展 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

<p>The mechanical and chemical properties of hydrogels make them excellent vehicles to deliver drugs. However, current systems encounter difficulties with loading hydrophobic molecules into the aqueous gel network and the subsequent release of the drug from the gel matrix. Cyclodextrins (CDs) offer a potential solution to this drug delivery challenge. CDs have the unique property of possessing a hydrophilic exterior and a hydrophobic interior pocket which is capable of hydrophobic drug binding. CD molecules complexed with hydrophobic drugs have been demonstrated to significantly increase the bioavailability of those drugs in free solution. Thus, if these nanodomains are introduced into microgels or hydrogels, we anticipate that significantly higher hydrophobic drug loadings may be achieved together with improved controlled release of these drugs based on the properties of the hydrogel or microgel phase. We have fabricated <em>in situ</em> gellable and degradable hydrogels and microgels based on combinations of CDs and either functionalized carbohydrates (dextran) or thermosensitive synthetic polymers (poly(N-isopropylacrylamide), PNIPAM). To achieve this goal, we designed a series of microgels with grafted or immobilized CD groups and used multi-functional CD as a reactive crosslinker for making injectable bulk hydrogels.</p> / Master of Applied Science (MASc)