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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Aditivos químicos para o tratamento da cana-de-açúcar in natura e ensilada (Saccharum officinarum L.) / Chemical additives for the treatment of green chopped and ensiled sugarcane

Mateus Castilho Santos 28 February 2007 (has links)
O objetivo do presente trabalho foi avaliar o efeito de aditivos químicos sobre as perdas de matéria seca, composição química, valor nutritivo e estabilidade aeróbia da cana-de-açúcar in natura ou ensilada. No primeiro experimento, a cana-de-açúcar foi ensilada em silos laboratoriais. O experimento foi desenvolvido em delineamento experimental inteiramente casualizado com quatro repetições por tratamento. Os tratamentos avaliados foram: L. buchneri, cal virgem e calcário em doses de 1,0 e 1,5% da MV e gesso a 1,0% da MV, diluídos em 40L de água por tonelada de massa verde. Após a abertura dos silos, foram realizadas avaliações de perdas, estabilidade aeróbia, valor nutritivo e composição química. Os tratamentos contendo fontes de CaO ou CaCO3 apresentaram maior recuperação de matéria seca e menores perdas totais e gasosas. Nesses tratamentos também foram observados menor teor de etanol e maior concentração de ácido lático e de carboidratos solúveis. Para as variáveis de valor nutritivo, as silagens tratadas com esses aditivos apresentaram alto teor de cinzas, menor teor de fibra, maior coeficiente de digestibilidade e pequena alteração da fração protéica. As silagens de cana-de-açúcar com gesso ou L. buchneri apresentaram desempenho semelhante a silagem controle para as variáveis acima mencionadas. No ensaio de estabilidade aeróbia, a silagem aditivada com 1,5% de cal virgem apresentou desempenho superior e semelhante as silagens com L. buchneri e gesso. De forma geral, durante a fase anaeróbia as silagens tratadas com fontes de CaO ou CaCO3 apresentaram desempenho superior. Entretanto, na fase aeróbia, somente o tratamento contendo 1,5% de cal virgem manteve desempenho satisfatório. O segundo experimento avaliou o tratamento em montes da cana-de-açúcar picada in natura com doses de cal virgem durante dez dias de exposição aeróbia. O experimento foi realizado em delineamento inteiramente casualizado com quatro repetições por tratamento e em arranjo fatorial 2x4 com medidas repetidas no tempo. O fatorial foi composto por dois modos de aplicação e quatro doses do aditivo (0, 0,5, 1,0 e 1,5% da MV). Durante o ensaio foram realizadas avaliações de estabilidade aeróbia, valor nutritivo e composição química. Para as variáveis de estabilidade aeróbia, a utilização de cal virgem foi efetiva em evitar o aquecimento da massa de forragem e reduzir as perdas de matéria seca. Para a avaliação químico-bromatológica, não foi constatada diferença nos teores de CHO´S entre os tratamentos. O tratamento da cana-de-açúcar com cal virgem elevou o pH e a fração mineral da forragem. Os maiores teores de proteína bruta foram observados para a forragem não aditivada, contudo os valores obtidos para os demais tratamentos estão dentro da amplitude relatada na literatura. Doses de 1,0% e 1,5% do aditivo foram efetivas em evitar a elevação nos teores de FDN e FDA da canade- açúcar. A fração hemicelulose sofreu solubilização parcial imediatamente após a aplicação do aditivo. Os maiores coeficientes de DVIVMS e DVIVMO foram observados para as doses altas do aditivo, no modo de aplicação a seco, principalmente nas primeiras horas após o tratamento. / The objective of this trial was to evaluate the effects of chemical additives over the dry matter losses, chemical composition, nutritive value and aerobic stability of green chopped and ensiled sugarcane. In the first trial, the sugar cane was ensiled in experimental silos. The trial was carried out in a completely randomized experimental design with four replicates per treatment. The treatments evaluated were: L. buchneri, CaO and CaCO3, 1.0 e 1.5% and Ca(SO4)2, 1.0% (wet basis), all of them diluted to 40L of water per ton of fresh forage. After the silos were opened, the following variables were analyzed: losses, aerobic stability, nutritive value and chemical composition. Higher recovery rates and lower dry matter losses and gaseous production were observed for the silages containing CaO or CaCO3. In these treatments were also observed lower ethanol production and higher lactic acid and water soluble carbohydrates contents. The analysis of nutritive value showed that the utilization of CaO and CaCO3 increased the ash content, diminished the fibrous portion, improved the organic and dry matter digestibility and resulted in small changes of the crude protein content. The utilization of L. buchneri and Ca(SO4)2 resulted in silages similar to the control treatment for these variables. In the aerobic stability assay, only the silage containing 1.5% of CaO maintained the best performance. The silages treated with L. buchneri or Ca(SO4)2 showed similar performance. In summary, the silages treated with CaO or CaCO3 showed the best performance in the anaerobic phase and in the aerobic assay, only the treatment containing 1.5% of CaO maintained the positive performance across both assay. In the second trial, the green chopped sugar cane was treated with doses of CaO in an aerobic assay during ten days. The trial was carried out as a completely randomized experimental design with four replicates in a factorial design with repeated measures. The factorial was composed by two application methods and by increasing doses of CaO (0, 0.5, 1.0 e 1.5% in FF). The following variables were analyzed during the assay: aerobic stability, nutritive value and chemical composition. During the aerobic assay, the treatment with CaO reduced the heating and the dry matter losses in fresh sugar cane. For the chemical composition and nutritive value, there were no differences between treatments for the water soluble carbohydrates concentration. The utilization of CaO increased the pH and ash content of forages. Higher levels of crude protein were observed for the control forage, however the utilization of CaO did not reduced significantly the crude protein value. Doses of 1.0 and 1.5% of CaO inhibited the NDF and ADF uprising contents in the fresh sugar cane. The hemicellulose portion was solubilized immediately after the addition of CaO. Higher IVDMD and IVOMD coefficients were observed for the forage treated with 1.0% of CaO applied dried, mainly during the period immediately after treatment.
112

Vodou rozpustná jádra pro hliníkové slitiny a jejich vliv na povrchovou jakost odlitků / Water soluble cores for aluminum alloys and their influence on the surface quality of castings

Blažík, Petr January 2015 (has links)
The goal of this thesis is to examine a possible influence of the water soluble cores on the microstructure of commonly used aluminum alloys AlSi7Mg and AlSi10Mg in the lost wax technology. This thesis only deals with the changes of the eutecticum on the contact surface between the metal and the core and its surroundings where interactions can appear between the core based on the alkali salts NaCl and KCl and the alloy modified by sodium or strontium. The experimental part investigates the influence of the alkali salts on the modification additives and the modification of the structure itself.
113

Etude de la cristallisation d’une nouvelle molécule à efficacité cardiotonique dans un mélange liquide ionique - eau / Crystallization study of a new cardiotonic drug in an ionic liquid–water mixture

Resende de Azevedo, Jacqueline 25 March 2014 (has links)
La cristallisation par effet anti-solvant, comme technique de production de micro/nanoparticules, présente certains inconvénients. En effet, pour des molécules nouvellement synthétisées ou découvertes, comme le LASSBio-294, les solubilités dans l'eau et dans les solvants organiques sont faibles ce qui limite l'application de cette opération. L'utilisation de solvants alternatifs ouvre de nouvelles perspectives de recristallisation de ce type de molécules. Dans ce travail, nous nous sommes intéressés à la cristallisation du LASSBio-294 en utilisant un liquide ionique comme solvant. Ce sont des sels organiques fondus à température ambiante, qui ont la particularité d’avoir une tension de vapeur nulle. Ils constituent une nouvelle classe de solvants non volatiles et ininflammables qui présentent des propriétés originales. Dans un premier temps, des liquides ioniques (LIs) dérivés du cation imidazolium ont été utilisés comme solvant alternatif. La solubilité a été mesurée dans 5 LIs,dans l’eau et dans des mélanges eau/LI. Dans l’eau pure la solubilité est très faible (5 ppm). En revanche, dans certains LIs, elle est supérieure à 200 mg/g solution. Les résultats de solubilité dans des mélanges eau/LI ont permis de choisir le rapport eau/LI pour l’obtention d’un bon rendement en solide. En complément, une étude de la stabilité du solide en suspension a été menée dans différents systèmes aqueux. Cette étude a montré sa possible hydrolyse. Dans un deuxième temps, la recristallisation a été réalisée avec le 1-éthyl-3-méthylimidazolium méthyl phosphonate [emim][CH3O(H)PO2] comme solvant et l’eau comme anti-solvant. Deux approches sont présentées en vue de favoriser le mélange : l'utilisation de dispositifs de mélange et l'introduction des ultrasons pendant le processus de cristallisation. L’influence de paramètres tels que le rapport anti-solvant/solvant, la concentration initiale et la présence d'additifs a été étudiée. Les solides formés puis séchés en étuve ont été caractérisés par granulométrie laser, microscopie électronique à balayage, diffractométrie de rayons X, calorimétrie différentielle à balayage et test de dissolution. Malgré une diminution de la taille des particules élémentaires, l'état d'agglomération des cristaux obtenus n'a pas permis une augmentation de la vitesse de dissolution. En modifiant le mode de séchage (séchage par atomisation), cette agglomération est réduite et la dissolution améliorée. De plus, la présence d'un polymère entérique en solution lors du séchage par atomisation des cristaux synthétisés a eu un effet notable sur la structure des agglomérats formés. Ces derniers peuvent se désagréger, se disperser et se dissoudre rapidement. / The anti-solvent crystallization allows obtaining micro/nanoparticles, but it presents some disadvantages. In the case of new pharmaceutical molecules, as the LASSBio-294, the solubility in water or organic solvents is very low limiting the application of this operation. The use of Ionic Liquids (ILs) as alternative solvents opens new perspectives in pharmaceutical processing through anti-solvent crystallization process. Unlike conventional solvents, ILs are entirely composed of ions. ILs are organic salts, usually liquid at room temperature, and which are composed of a relatively large asymmetric organic cation and of an inorganic or organic anion. ILs derived from imidazolium cation are used as alternative solvents for this drug, water being used as anti-solvent. First, the solubility is measured in 5 ILs, in water and in water/IL mixtures. In pure water, the solubility is very low (5 ppm). However, for some ILs, it is greater than 200 mg/g solution. The results of solubility in water/IL mixtures permit to choose a water/IL ratio leading to a good solid theoretical yield. Then recrystallization is performed with 1-ethyl-3-methylimidazolium methyl phosphonate [emim][CH3O(H)PO2] as the preferred solvent. Antisolvent crystallization represents a class of process characterized by the mixing between a solution and an antisolvent to produce solid particles. The influence of solvent/anti-solvent ratio, initial concentration, and additives is studied. The solids formed and dried in an oven are characterized by laser granulometry, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and dissolution test. Despite the decrease of elementary particles size, the agglomeration state of particles does not permit to improve the dissolution rate. The agglomeration is reduced and the dissolution improved by modifying the drying process (spray drying). Moreover, the presence of an enteric polymer during the spray drying process has a significant impact on the structure of the formed agglomerates. These are disaggregated, dispersed and dissolved very quickly.
114

Efficacy of water soluble silicon for control of phytophthora cinnamomi root rot of avocado

Bekker, Theo Frederik 17 September 2007 (has links)
In the current study potassium silicate (20.7% SiO2) induced a 100% inhibition of P. cinnamomi mycelial growth at all concentrations tested. Total inhibition for all fungi tested (Alternaria solani, Colletotrichum gloeosporioides, Curvularia lunata, Drechslera sp., Fusarium oxysporum, Fusarium solani, Glomerella cingulata, Lasiodiplodia theobromae, Mucor pusillus, Natrassia sp., Pestalotiopsis maculans, Phomopsis perniciosa, Phytophthora capsicii, Phytophthora cinnamomi, Pythium F-group, Sclerotinia sclerotiorum, Sclerotium rolfsii, Stemphylium herbarum and Verticillium tricorpus) was attained at a concentration of 40ml.l-1 and higher. Although the high pH of potassium silicate solutions does contribute to the inhibition of fungal growth, the inhibitory effect of potassium silicate on fungal growth in vitro is mostly fungicidal rather than attributed to a pH effect. Phytophthora root rot of avocado nursery trees can be inhibited successfully by potassium silicate application. The effectiveness of potassium silicate application depends however on the repetition of applications. These findings are of paramount importance as this implies that potassium silicate may be a alternative control measure to inhibit the effects of P. cinnamomi on avocado nursery trees. Silicon either stimulates plant growth or imparts some form of protection to avocado roots if applied prior to P. cinnamomi inoculation. Potassium silicate applied as a soil drench resulted in higher root densities compared to that of potassium phosphonate (Avoguard®) injections and untreated control trees. Reapplication again resulted in the best disease suppression and stimulation of new root growth. These results correlated well with tree canopy ratings, as trees that received silicon frequently, showed better canopy conditions compared to the untreated control treatments. Potassium silicate application leads to effective inhibition of Phytophthora cinnamomi infection in avocado orchards. Potassium silicate application resulted in an increase of crude phenols and phenolic polymers in avocado roots cells to similar levels to that obtained in roots from potassium phosphonate (Avoguard®) treated trees. Potassium silicate application leads to lower cell wall bound phenolics. The results of the current study support the hypothesis that silicon application, through an elevation of the total phenolic levels, causes an increase of resistance against P. cinnamomi root rot in avocados. AFRIKAANS : Kaliumsilikaat (20.7% SiO2) induseer ‘n 100% inhibisie van P. cinnamomi groei by alle getoetste konsentrasies. Totale inhibisie van alle swamme getoets (Alternaria solani, Colletotrichum gloeosporioides, Curvularia lunata, Drechslera sp., Fusarium oxysporum, Fusarium solani, Glomerella cingulata, Lasiodiplodia theobromae, Mucor pusillus, Natrassia sp., Pestalotiopsis maculans, Phomopsis perniciosa, Phytophthora capsicii, Phytophthora cinnamomi, Pythium F-groep, Sclerotinia sclerotiorum, Sclerotium rolfsii, Stemphylium herbarum en Verticillium tricorpus) was verkry by ‘n konsentrasie van 40ml.l-1 en hoër. Alhoewel die hoë pH van kaliumsilikaat wel ‘n inhiberende uitwerking het op swamgroei, is die suksesvolle inhibisie van swamgroei grootliks toe te skryf aan die swamwerende effek van kaliumsilikaat op swamgroei in vitro eerder as ‘n pH effek. Phytophthora wortelvrot van avokado kwekelinge kan suksesvol onderdruk word met kaliumsilikaat toediening. Die effektiwiteit van die toediening hang wel af van die hertoediening daarvan. Hierdie bevindinge is van kardinale belang aangesien dit impliseer dat kalium silikaat ‘n alternatiewe beheer middel is om Phytophthora wortelvrot te inhibeer in avokado kwekelinge. Of silikon stimuleer plant groei, of dit induseer ‘n vorm van beskerming in avokado wortels voor infeksie plaasvind. Kaliumsilikaat toediening as ‘n grond-benatter lei tot hoër worteldigthede in vergelyking met kaliumfosfaat (Avoguard®) staminspuitings en onbehandelde kontrole bome. Hertoediening lewer die beste resultate, maar drie toedienings per seisoen is voldoende. Worteldigdheid verhoging na silikaat toedienings korreleer goed met blaredak gesondheid, aangesien bome wat gereeld behandel is met silikon beter blaredekking getoon het in vergelyking met die kontrole bome. Kaliumsilikaat toediening lei to effektiewe inhibisie van Phytophthora cinnamomi infeksie in avokado boorde. Kaliumsilikaat toediening lei tot ‘n toename in totale fenole en fenoliese polimere in avokado wortel selle tot soortgelyke vlakke soos gevind in avokado weefsel vanaf kaliumfosfaat behandelde bome. terselfdertyd lei silikaat toediening tot laer selwand gebinde fenole. Hierdie resultate ondersteun die hipotese dat kaliumsilikaat toediening, deur die verhoging van oplosbare fenole in avokado wortelselle, die plant se weerstand verhoog, en die effek wat Phytophthora wortelvrot het op avokado plante inhibeer. Copyright / Dissertation (MSc (Agric) Horticulture)--University of Pretoria, 2011. / Plant Production and Soil Science / unrestricted
115

Alanine, aspartic acid and lactose-capped CuS, ZnS and FeS nanoparticles: synthesis, characterization and properties

Mofokeng, Thapelo Prince January 2017 (has links)
M. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology / Water soluble metal sulfide nanoparticles were successfully synthesized using an aqueous, simple and environmentally friendly synthetic method in the presence of ʟ-alanine, ʟ-aspartic acid and lactose, acting as both stabilizers and crystal growth modifiers. The structural and optical properties of the synthesized metal sulfide nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), Ultraviolet-visible (UV-Vis) and photoluminescence spectroscopy. Colloidal method was employed in the synthesis of CuS, ZnS and FeS nanoparticles from metal chlorides as precursors and thioacetamide (TAA) as a sulphur source. The effect of temperature on the growth and solubility of nanoparticles was investigated. The absorption spectra of all samples prepared were blue shifted as compared to their bulk materials indicating small particles size. The morphologies and sizes of the nanoparticles were influenced by the variation of temperature and capping agent. TEM images revealed interesting changes in the morphology of CuS nanoparticles formed from various capping agents. By varying the temperature, ʟ-aspartic acid-capped CuS nanoparticles changed from rod-shaped particles to particles dominated with hexagonal shape. However, the morphologies of both ZnS and FeS nanoparticles were close to spherical shape and were unaffected by either change of temperature or capping agent. Water-solubility of bio-functionalized CuS, ZnS and FeS nanoparticles was investigated. Amongst the three capping agents used, ʟ-alanine (Ala) was found to be the most effective capping agent to render solubility of the nanoparticles. As the temperature was increased, the solubility of the particles also increased. Cytotoxicity and antimicrobial activity of ʟ-alanine-capped CuS and ZnS nanoparticles were investigated. The particles were less toxic at low to moderate concentrations and only induced toxicity at higher concentrations. Particles synthesized at 95 °C were less toxic compared to other nanoparticles (35 and 65 °C) for both two set of experiments, as informed by the CC50 values. Antimicrobial properties were tested using different strains of both positive and negative bacteria and fungi. It was found that Ala-capped CuS nanoparticles were more effective against the bacteria than Ala-capped ZnS nanoparticles.
116

BIOMIMETIC DISSOLUTION: A TOOL TO EVALUATE AMORPHOUS SOLID DISPERSION PERFORMANCE

Puppolo, Michael McBride January 2017 (has links)
The pharmaceutical industry is at a critical juncture. With little remnants of the “Golden Age of the Pharmaceuticals” and applied pressure from large companies experiencing a dissipation of proprietary compounds, trends indicate a transition from a decade of stagnant productivity to one in which high throughput screening technologies and computational chemistry have diversified the discovery of new chemical entities (NCE). Despite these advances, drug discovery has been challenged by chemical entities that present delivery limitations due to the properties of their molecular structure. A recent evaluation of development pipelines indicated that approximately 70% of drug candidates exhibit poor aqueous solubility; thereby, resulting in erratic dissolution and insufficient bioavailability. Due to intrinsic physical properties, these compounds are known by the biopharmaceutics classification system (BCS) as class II compounds and are amendable to solubility and bioavailability enhancement platforms. Approaches such as pH adjustment, micronization, nanosuspensions, co-solvent solubilization, cyclodextrin inclusion complexation, salt formation, emulsified drug formulations and amorphous solid dispersions (ASD) are commonly utilized to maximize bioavailability and enrich in vivo absorption by prolonging exposure to high concentrations of dissolved drug in the gastrointestinal tract (GIT). Single-phase amorphous systems, such as solid dispersions, have been the focal point of the aforementioned practices as a result of their ability to promote a state of drug supersaturation over an extended duration of time. Within the structure of this dissertation, the application of concentration enhancing polymers for bioavailability enhancement of low solubility compounds was evaluated using solvent and fusion-based solid dispersion technologies. Exploiting a variety of analytical methodologies and tools, formulations produced by spray drying and hot melt extrusion (HME) techniques were investigated for sufficient dissolution enhancement. Studies revealed the selected formulation approaches provided a viable platform for manufacturing solid dispersions by illustrating systems that offered rapid and prolonged periods of supersaturation. While of the applications of single-phase amorphous solid dispersions are continuously expanding, their dissolution behavior is not as well understood. The overarching objective of dissolution testing during formulation development is to achieve biological relevance and predict in vivo performance. Proper in vitro dissolution testing can convey the influence of key in vivo performance parameters and be implemented for assessment and comparison of ASD formulations. Studies suggest that existing research fails to accurately address the intricacies associated with the supersaturated state. Upon solvation and during transit in the GIT, several high-energy drug-containing species are present in addition to free drug. Although these species are not absorbed in vivo, they play a pivotal role in generating and maintaining the supersaturation of a drug substance and function to replenish the supply of free drug as it permeates across the gastrointestinal membrane. Established dissolution apparatuses and methodologies in the United States Pharmacopeia (USP) focus on evaluation of total dissolved drug and may not be physiologically relevant for determining the amount of drug absorbed in vivo. Within the framework of this dissertation, a dissolution methodology was designed to reflect the physiochemical, physiological and hydrodynamic conditions that transpire throughout dissolution and absorption of an ASD during transit in the GIT. The apparatus and model present the ability to understand the kinetics and mechanisms of dissolution, supersaturation and nucleation. To support this hypothesis, analytical methods including high pressure liquid chromatography (HPLC) with ultraviolet (UV) detection were developed and fully validated. In parallel, a novel plasma membrane treatment was established to fabricate biomimetic membranes that possessed a hydrophilic and hydrophobic surface. The treated membranes are comprised of applied surface chemistries that emulate the unstirred aqueous layer created by microvilli protruding from the intestinal epithelial membrane as well as lipophilic constituents corresponding to the epithelial lipid membrane. Calculated in vitro similarity (f2) and difference (f1) factors support the hypotheses that plasma treated microporous polymer membranes exhibit biorelevant properties and demonstrate adequate biorelevance for in vitro dissolution studies. The described dissolution methodology has been applied as a tool for selection of candidates to move forward to pharmacokinetic studies. In a culminating study, in vitro – in vivo correlations (IVIVC) were performed employing the universal membrane-permeation non-sink dissolution method for formulations of Carbamazepine. To demonstrate the utility of the methodology, multiple level C correlations were established. The membrane-permeation model enables quantitative assessment of drug dissolution and absorption and offers a means to predict the relative in vivo performance of amorphous solid dispersions for BCS class II drug substances. / Chemistry
117

THE EVALUATION OF LARCH ARABINOGALACTAN AS A NEW CARRIER IN THE FORMULATION OF SOLID DISPERSIONS OF POORLY WATER- SOLUBLE DRUGS

Thakare, Kalpana January 2013 (has links)
Advanced drug discovery techniques have produced more lipophilic compounds. Formation of an amorphous solid dispersion of such poorly water-soluble drugs improves their solubility and dissolution. This results in greater in vivo bioavailability. Thus, it is one of the recent trends in the development of oral dosage forms. In solid dispersions, the carrier is crucial for ensuring the functionality and stability of these systems. Larch arabinogalactan FiberAid grade (AGF) is generally recognized as safe (GRAS) designated, amorphous polymer. The objective of this dissertation project was to perform a comprehensive evaluation of AGF as a carrier for amorphous solid dispersions. First, a detailed characterization of the AGF polymer was performed. A special focus on its use as a solid dispersion carrier was emphasized. The glass transition temperature and the degradation temperature of the AGF polymer were ~82 oC and ~185 oC, respectively. The AGF polymer had good hygroscopicity. Ibuprofen-AGF solid dispersions were evaluated for dissolution enhancement. Ibuprofen-Hydroxypropyl methylcellulose grade K3 (HPMCK3) solid dispersions were investigated simultaneously as a control polymer dispersion. The ibuprofen-AGF solid dispersions were amorphous at nearly 20% ibuprofen load. The dissolution of the ibuprofen from AGF solid dispersions was significantly greater than that of the neat ibuprofen. The formation of the amorphous state of ibuprofen and solution-state ibuprofen-AGF interactions were the mechanisms of the ibuprofen dissolution enhancement. At a 10% ibuprofen load, the dissolution of the AGF solid dispersion was found greater than that of the dissolution of the HPMCK3 solid dispersion. Secondly, the itraconazole-AGF solid dispersions and the ketoprofen-AGF solid dispersions were characterized and compared them with the ibuprofen-AGF solid dispersions. The comparisons were established for the miscibility and dissolution enhancement. The order of increase in dissolution was ketoprofen-AGF solid dispersions > itraconazole-AGF solid dispersions> ibuprofen-AGF solid dispersions. The same order was observed for the solid-state miscibility of these drug-AGF solid dispersions. Additionally, the solid dispersions of 9 drugs with the AGF polymer were investigated to elucidate the detailed mechanism of drug crystallization inhibition by the AGF polymer. The inherent tendency of the AGF polymer to inhibit the drug crystallization, drug-AGF solid-state hydrogen bonding and the anti-plasticizing effect of AGF were the mechanisms underlying the crystallization inhibition by the AGF polymer. Last, a storage stability of ibuprofen-AGF amorphous solid dispersions after storage under accelerated conditions (for 3 months) and ambient conditions (for 6 months) was investigated. The amorphous ibuprofen from AGF solid dispersions was physically and chemically stable under stability conditions. In summary, the AGF polymer was evaluated as a novel carrier for formation of an amorphous solid dispersions. The studies established that the AGF polymer was comparable to HPMCK3 polymer. The AGF polymer could be more advantageous than the HPMC polymer for the preparation of solid dispersion when faster dissolution is desired at lower drug load. / Pharmaceutical Sciences
118

Water-Soluble Helical Polymers as Chiral Catalysts in Asymmetric Reactions in Water / 水中不斉反応のキラル触媒のための水溶性らせん高分子

Kamiya, Naoaki 23 May 2023 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第24817号 / 工博第5160号 / 新制||工||1986(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 杉野目 道紀, 教授 生越 友樹, 教授 大内 誠 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
119

Functionalization of Nanocarbons for Composite, Biomedical and Sensor Applications

Kuznetsov, Oleksandr 24 July 2013 (has links)
New derivatives of carbon nanostructures: nanotubes, nano-onions and nanocrystalline diamonds were obtained through fluorination and subsequent functionalization with sucrose. Chemically modified nanocarbons show high solubility in water, ethanol, DMF and can be used as biomaterials for medical applications. It was demonstrated that sucrose functionalized nanostructures can find applications in nanocomposites due to improved dispersion enabled by polyol functional groups. Additionally, pristine and chemically derivatized carbon nanotubes were studied as nanofillers in epoxy composites. Carbon nanotubes tailored with amino functionalities demonstrated better dispersion and crosslinking with epoxy polymer yielding improved tensile strength and elastic properties of nanocomposites. Reductive functionalization of nanocarbons, also known as Billups reaction, is a powerful method to yield nanomaterials with high degree of surface functionalization. In this method, nanocarbon salts prepared by treatment with lithium or sodium in liquid ammonia react readily with alkyl and aryl halides as well as bromo carboxylic acids. Functionalized materials are soluble in various organic or aqueous solvents. Water soluble nanodiamond derivatives were also synthesized by reductive functionalization of annealed nanodiamonds. Nanodiamond heat pretreatment was necessary to yield surface graphene layers and facilitate electron transfer from reducing agent to the surface of nanoparticles. Other carbon materials such as activated carbon and anthracite coal were also derivatized using reductive functionalization to yield water soluble activated carbon and partially soluble in organic solvents anthracite. It was shown that activated carbon can be effectively functionalized by Billups method. New derivatives of activated carbon can improve water treatment targeting specific impurities and bio active contaminants. It was demonstrated that functionalized carbon nanotubes are suitable for real time radiation measurements. Radiation sensor incorporating derivatized carbon nanotubes is lightweight and reusable. In summary, functionalization of carbon nanomaterials opens new avenues for processing and applications ranging from biomedicine to radiation sensing in space.
120

Hydrosolubilizace skeletu BODIPY pro optické značení biomolekul / Hydrosolubilization of BODIPY for optical labelling of biomolecules

Bartoň, Jan January 2015 (has links)
1 Abstract This work aims at showing synthesis and potential use of water-soluble fluorescent probes based on BODIPY. The preparation of probes containing bioorthogonal mono- and heterobifunctional functional groups was demonstrated. Ground work was done at the optimisation of reliable, scalable and fast sulfonation of BODIPY in 2,6-positions. A protocol for handling sulfonated BODIPY has been established; especially for the exchange of counterions. In counterion se- lection, their relation to synthetic pathway and biocompatibility were taken into consideration. The second part of the work shows series of water-soluble fluorescent probes, into which can be easily introduced bioactive or bioorthogonal functional groups. This can be used for click chemistry in connection with turn off/on probes or fluorescent sensing of molecules or ions. All this can be done in aqueous solution without organic solvents, which is relevant for biochemical, analytical and imaging applications. Keywords BODIPY, bifunctional, water-soluble, fluorescent probe, solubilization, biocompa- tible probes, bioorthogonal reaction, BODIPY sulfonation

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