• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 86
  • 33
  • 9
  • 7
  • 3
  • 3
  • 3
  • 2
  • 2
  • 1
  • Tagged with
  • 181
  • 34
  • 19
  • 15
  • 15
  • 15
  • 14
  • 12
  • 11
  • 11
  • 11
  • 10
  • 10
  • 10
  • 9
  • 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.
41

Materials engineering through cocrystallization and nanoprecipitation of selected drugs for potential manufacturing and therapeutic applications.

January 2014 (has links)
引子: 共晶技術和納米沉澱技術於近年被廣泛討論能改進藥物性質和提高體內性能。本論文研究旨在將該兩種技術嘗試應用於五種模型藥物中,分別是薑黃素(CUR),氟比洛芬(FLU),布洛芬(IBU),酮洛芬(KET) 和環氧洛芬(LOX)。這些藥物均難溶於水,擁有較差機械性質,相對高的親油性和潛在治療腦退化症的功用。在共晶技術中,藥物將會與煙酰胺(NCT)先溶於在溶劑中,透過蒸發以誘發共晶產生。另一方面,瞬時納米沉澱(FNP)技術會將藥物溶液(包含穩定劑)與反溶劑在封閉衝擊射流混合器(CIJM)或多入口渦旋混合器(MIVM)快速混合,生成納米藥物。 / 方法: 將藥物和NCT溶於乙醇中,應用旋轉蒸發或簡單蒸發生成共晶。透過不同的檢測方法,包括X射線衍射,差示掃描量熱法,熱重分析,吸濕分析,傅立葉變化紅外線光譜,特性溶出速率量度法和壓實分析將共晶檢定。另一方面,利用CIJM或MIVM,藥物在不同的混合速率,溶劑性質,聚乙二醇-聚乳酸(穩定劑)分子重量或藥物對聚合物比的工藝環境下載入於納米粒子中。生產出來的納米藥物會利用動態光散射測定粒徑; 電泳光散射法測定zeta電位; 掃描電子顯微鏡和原子力顯微鏡測定粒子形貌和其表面性質; X-射線光電子能譜測定表面成分; 高效液相色層分析測定載藥量和包封率。 / 結果: 利用旋轉蒸發,高純度的1:1 IBU-NCT 和FLU-NCT 的共晶能成功生成,但KET-NCT和LOX-NCT 共晶則不能獲得。低純度的CUR-NCT 共晶可根據相同技術取得。相比原來藥物而言,IBU-NCT 和FLU-NCT 共晶均有較好的機械性質,抗吸水性和溶解速度。而在FNP研究中,証實了混合速率,溶劑性質,聚乙二醇-聚乳酸(穩定劑)分子重量或藥物對聚合物比均對生產出來的納米粒子的粒徑有重要影響。另外,納米粒子的穩定性可籍添加輔助穩定劑(如PVA)大幅提高。XPS分析証實輔助穩定劑能與在粒子表面的聚乙二醇起相互作用,更佳地保護粒子。而在一系列對四種不同的洛芬藥物的實驗中,多次線性回歸分析指出三種有關藥物的溶液性質(即溶解度,分配係數和酸度系數)會對生成的納米粒子的粒徑和包封率有顯著影響。 / 結論: 將IBU和FLU與NCT結成共晶能同時提高其機械性質,抗吸水性和溶解速度。而在FNP中,優化不同工藝參數能有效控制納米藥物的粒徑,形態,表面性質和穩定性。 / Introduction: In recent years, cocrystallization and nanoprecipitation have gained increasing popularity as viable strategies for improving the pharmaceutical properties and in vivo performance of drugs. The present thesis was aimed at assessing these two approaches for potential applications in pharmaceutical formulation and manufacture with five model drugs, viz. curcumin (CUR), flurbiprofen (FLU), ibuprofen (IBU), ketoprofen (KET) and loxoprofen (LOX). Selection of these drugs for the study was guided mainly by their poor water solubility, poor compactibility, typical drug‘s lipophilicity (log P =3-5), and potential for treatment of Alzheimer‘s disease. Cocrystallization was induced by the attainment of a sufficient supersaturation level through rapid solvent removal from a solution containing the drug and the coformer, nicotinamide (NCT), while flash nanoprecipitation (FNP) was achieved by rapid and homogenous mixing of drug solution (with stabilizer and co-stabilizer if required) with antisolvent in the mixing chamber of a specially designed confined impinging jet mixer (CIJM) or multi-inlet vortex mixer (MIVM). / Methods: Cocrystals were prepared by rotary solvent evaporation or slow evaporation of a solution of drug and NCT in ethanol, and characterized by powder X-ray diffraction, differential scanning calorimetry, thermogravimetry, moisture sorption analysis, Fourier transform infrared spectroscopy, intrinsic dissolution rate (IDR) measurement and compaction analysis. Polymer-stabilized drug nanoparticles were prepared by FNP using a two-stream CIJM or four-stream MIVM under defined conditions of varying flowrate, solvent type, molecular weight of amphiphilic diblock (PEG-PLA) copolymer (stabilizer), or drug-to-copolymer ratio. The resulting nanoparticles were characterized for particle size by dynamic light scattering; zeta potential by electrophoretic light scattering; particle morphology and surface properties by scanning electron microscopy and atomic force microscopy; surface composition by X-ray photoelectron spectroscopy (XPS); and drug loading and encapsulation efficiency (EE) by high performance liquid chromatography. / Results: Phase-pure 1:1 cocrystals of IBU and FLU with NCT were obtainable by rotary solvent evaporation, but not slow evaporation. Similar solvent removal failed to cause any cocrystal formation for KET and LOX while inducing partial cocrystal conversion for CUR. Both IBU-NCT and FLU-NCT cocrystals displayed enhanced IDR, reduced moisture sorption and improved tabletability compared with the individual profen crystals. FNP studies using the MIVM confirmed the flowrate, solvent type, molecular weight of PEG-PLA copolymer, and drug-to-copolymer mass ratio being important process variables for controlling particle size and particle stability. Particle stability could be enhanced with a hydrophilic co-stabilizer (e.g., PVA). Such co-stabilizers possibly act by binding to the PEG corona at the particle surface to reinforce the protective steric barrier, as substantiated by XPS data. Comparative studies on nanoparticle production by FNP for the four profens indicated that three structure-related intrinsic solution properties of the profens, namely, water solubility, log P and pKa, were important determinants of the particle size and EE of nanoparticles, as determined by multiple linear regression analysis. / Conclusion: Cocrystallization with NCT can simultaneously improve the tableting behavior, hygroscopicity, and dissolution performance of IBU and FLU. Proper optimization of the process variables in FNP is critical to the controlled production of polymer-stabilized drug nanoparticles with consistent properties and storage stability. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chow, Shing Fung. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 224-247). / Abstracts also in Chinese.
42

Comparison of two methods for differentiating negative from inconclusive GC-MS test results using an isotopic analog of the analyte as the internal standard -- 11-nor-[delta]⁹-tetrahydrocannabinol-9-carboxylic acid example

Waters, Laura S. January 2008 (has links) (PDF)
Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Description based on contents viewed June 2, 2008; title from title screen. Includes bibliographical references (p. 32).
43

The consequences of fetal exposure to analgesics for germ cells

Hurtado Gonzalez, Pablo Ignacio January 2018 (has links)
Despite the general advice of avoiding medication during pregnancy, the majority of pregnant woman use one or more ‘over the counter’ analgesics. During the last few years there has been growing evidence that analgesic exposure, such as paracetamol, ibuprofen or indomethacin, during pregnancy can have detrimental effects on rodent and human fetal gonads. The majority of previous studies have focused in alterations in testosterone production and male reproductive disorders. However, few studies have analysed the effect of these analgesics on fetal germ cells and possible consequences on fertility. During my thesis, I first focused on the effect of paracetamol and indomethacin exposure during pregnancy on rat fetal gonads. These showed that both paracetamol and indomethacin are able to alter the expression of genes important for fetal gonad and germ cell development. Previous studies on germ cells and analgesics have focused on rat models, but there is a lack of similar studies performed in human models. Therefore, I investigated the consequences of exposure of therapeutically relevant doses of paracetamol and ibuprofen on human gonads, with a special attention to the germ cells. Fetal gonads from the 1st and 2nd trimester were used in two different models: hanging drop cultures for 1st trimester testes and ovaries and a xenograft system for 2nd trimester fetal testes. Fetal gonad culture in the presence of paracetamol or ibuprofen reduced AP2γ+ (gonocyte) GC number in both 1st trimester fetal testes (22-28% reduction) and ovaries (43-49% reduction). 2nd trimester fetal testes were exposed to three different regimes, 1 or 7 days paracetamol and 7 days ibuprofen, which led to reductions of 17% and 30%, respectively in AP2γ+ GC number for paracetamol and a 53% reduction in total germ cell number for ibuprofen.
44

Preparation of novel modified-release dosage forms of diclofenac sodium and ibuprofen

Sujja-Areevath, Jomjai January 1997 (has links)
Mini-matrix multiple unit dosage forms (MUDFs) of diclofenac sodium and S(+) ibuprofen have been prepared. Normal tabletting techniques were used to form the mini-matrices prior to their enclosure in hard gelatin capsules. Four natural hydrophilic gums, namely xanthan, karaya, locust bean and carrageenan gums as well as hydroxypropyl methylcellulose (HPMC) were used as the principle release-retarding agents. Various excipients - lactose, Encompress®, cellulose acetate phthalate (CAP), Veegum F® and Avicel PH101® - were added in different proportions to further modify drug release. The diclofenac sodium mini-matrices (4.5 mm in diameter) were produced by the wet granulation method. The release profiles from several encapsulated minimatrices in phosphate buffer solution (pH 7.0) showed that xanthan, karaya and locust bean gums could sustain the release of diclofenac sodium while the carrageenan gum did not produce a satisfactory sustaining effect. The rank order of decreasing swelling rate in both axial and radial dimensions was xanthan > karaya > locust bean gum and each of these gums showed almost Fickian swelling behaviour. The solvent penetration rates were consistent with the swelling rates. However, the order of decreasing drug release and erosion rates was locust bean> xanthan > karaya gum. For each of these gums, the release behaviour was anomalous indicating that both Fickian drug diffusion and polymer relaxation were involved in the release process. The dominant mechanism depended on the nature and content of the gum, as well as the stage in the dissolution period. The study involving xanthan gum showed that the diclofenac sodium release rate declined linearly with a progressive increase in the gumcontent, without changing the release behaviour. However, for high drug: xanthan gum ratio (2:1), the release kinetics changed to Super Case II. Solubility differences between the excipients did not affect the release rate, but increasing proportions of each excipient produced a faster release rate with the release mechanism changing from anomalous to Case II and then to Super Case II transport. Mini-matrices containing HPMC produced faster drug release than those containing the three natural gums. There was no synergistic effect between xanthan and locust bean gums on the release of diclofenac sodium from mini-matrices. Variation in the stirring speed (used in the dissolution apparatus) and matrix volume had little effect on drug release, whereas the pH of the dissolution medium greatly affected the release of diclofenac sodium. Following on from the studies involving diclofenac sodium, xanthan and karaya gums were used to produce mini-matrices of S(+) ibuprofen. Excipients with good compressibility characteristics such as lactose, Encompress® and Avicel PH101® were needed in the formulations. At pH 7, higher drug release rates were obtained with karaya gum (Super Case II mechanism) compared with xanthan gum (anomalous behaviour). Solubility differences between the excipients slightly affected the release rate. Compression forces (11 - 26 kN) slightly affected the crushing strength. The minimatrices were relatively stable to variation in temperature (5 - 37°C) and relative humidity (10 - 75%) over a 2 month time period. These studies have shown that near zero-order release of diclofenac sodium and S(+) ibuprofen can be achieved using encapsulated mini-matrices formulations. The release mechanisms and release rates can be adjusted by variation of the type and content of gums and/or excipients.
45

Guar Gum/Montmorillonite Nanocomposites and Their Potential Application in Drug Delivery

Dziadkowiec, Joanna January 2016 (has links)
Clays are ubiquitous near the Earth’s surface. Medicinal properties of these nontoxic minerals have been intuitively recognized since ancient times. Up till now, clays have been used in pharmaceutical formulations as active agents and excipients. Currently, there is an urgent need to seek advanced, functional materials with low environmental impact. Answering to that trend, clay-biopolymer nanocomposites were synthesized in this thesis and applied in a drug delivery system. In the first part of the thesis, Portuguese clay from a bentonite deposit in Benavila (Portugal) was collected from six sampling sites and characterized. The highest content of clay fraction, approximately 30%, was found in two of the sampling sites. After purification, the smectite-rich samples were analyzed with respect to clay content, mineralogical and chemical composition, physicochemical and mechanical properties. SEM-EDS revealed that the smectite present in the ore is montmorillonite with varying Fe content. This was also indicated by the means of XRD, XRF and FTIR. The Benavila sample, which was richest in smectite, as well as the sodium Wyoming montmorillonite from the Source Clay Repository (SWy-2) were successfully used to synthesize clay-biopolymer nanocomposites. The chosen biopolymers were the plant-extracted polysaccharides – neutral guar gum and its cationic form. The obtained materials were thoroughly characterized by XRD, TGA and NMR, and the intercalated structure was reported. The prepared nanocomposites were loaded with an anti-inflammatory drug ibuprofen and tested in an in-vitro release system. The drug-loaded materials were characterized with XRD, TGA and NMR. A membrane diffusion method was chosen as a dissolution testing strategy and the drug was quantified by UV-Vis spectroscopy. The materials exhibited improved properties as a noticeable reduction of release rate was achieved.
46

Desenvolvimento de um sensor potenciometrico para ibuprofeno / Development of a potenciometric sensor for ibuprofen

Ribeiro, Paulo Jose Fernandes 14 July 2006 (has links)
Orientadores: Lauro Tatsuo Kubota, Graciliano de Oliveira Neto / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-08T00:59:06Z (GMT). No. of bitstreams: 1 Ribeiro_PauloJoseFernandes_M.pdf: 3526765 bytes, checksum: d7527897c70e194a6207d1020f2ce8bc (MD5) Previous issue date: 2006 / Resumo: Nesse trabalho é apresentado o desenvolvimento de um eletrodo íon-seletivo para determinação de ibuprofeno, utilizando-se membrana do copolímero poli(etileno co-acetato de vinila) (EVA), tentando minimizar o uso de plastificantes. A membrana foi preparada diretamente sobre um suporte condutor constituído de uma mistura de resina epóxi, endurecedor e grafite. Na preparação da membrana foram estudadas diversas proporções de seus componentes, como concentração de par-iônico, influência do plastificante e quantidades de matriz polimérica. As melhores respostas foram obtidas com uma membrana composta de 115 mg do par-iônico aliquat-ibuprofeno, 170 mg de EVA e 150 mg do plastificante o-NPOE (orto-nitrofeniloctil-éter), não sendo possível eliminar o plastificante. Com o objetivo de otimizar as condições analíticas, foram feitos estudos da influência do pH, da natureza e concentração do tampão e de interferentes, além do tempo de reposta e de vida do eletrodo. As melhores respostas em estado estacionário foram obtidas em tampão Fosfato com concentração de 0,5 mol L a pH 7.0. Nestas condições foi verificado um bom desempenho do eletrodo na faixa de concentração de 2,93 10 a 10mol L, com limite de detecção de 8,7 10 mol L, sensibilidade de 127 mV década, tempo médio de resposta de 56 s e capacidade para aproximadamente 100 determinações. O eletrodo foi aplicado para determinação de ibuprofeno em amostras de medicamento obtendo bons resultados, sendo estes estatisticamente igual aos obtidos com o método de referência a um nível de 95% de confiança. / Abstract: In this work is presented the development of an ion-selective electrode for ibuprofen determination, using the poly(ethylene-co-vinyl-acetate) copolymer (EVA) membrane, trying to minimize the use of plasticizer. The membrane was prepared directly on a conducting support consisting of an epóxi resin, hardener and graphite mixture. In the preparation of the membrane several ratios of its components were investigated, such as concentration of ion-pair, influence of the plasticizer and polymeric matrix. The best performance was reached with a membrane composed with 115 mg of the ibuprofen-aliquat ion-pair, 170 mg of EVA and 150 mg of the o-NPOE (orto-nitrophenyloctyl-ether), being impossible to eliminate the plasticizer. Studies of the influence of pH, nature and concentration of the buffer and the interfering were carried out looking for the optimized conditions for the electrode performance like sensitivity, fast response and lifetime. The best response was obtained with Phosphate buffer in a concentration of 0,5 mol L at pH 7.0. In these conditions the electrode showed a good performance in the concentration range between 2,93 10 and 10 mol L, with a sensitivity of 127 mV/decade, a detection limit of 8,7 10 mol L, response time of 56 s and capacity for 100 determinations. The electrode was employed to determine ibuprofen in medicine samples obtaining good results, being statistically equal at 95% confidence level, when compared with the results obtained with the reference method for the same samples. / Mestrado / Quimica Analitica / Mestre em Química
47

Analýza postojů seniorů na samoléčení analgetiky se zaměřením na nesteroidní antiflogistika / The Analysis of Senior's Opinions on Self-treatment by non-steroidal anti-inflamatory drugs

Kliui, Yuliia January 2020 (has links)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Social and Clinical Pharmacy Candidate: Yuliia Kliui Consultant: PharmDr. Martin Doseděl PhD. Title of the diploma thesis: The Analysis of Senior's Opinions on Self-treatment by non- steroidal anti-inflammatory drugs Introduction: Due to their significant analgesic and antiphlogistic effects are non-steroidal anti-inflammatory drugs one of the most prescribed drugs. According to the high number of side effects and drug-drug interactions, it is important to pay attention to their presence in patient's medication. The importance of drug related problems increases in polymorbid and geriatric patients, who's medication can be altered by the presence of non-steroidal anti-inflammatory drugs, which can lead to unwanted complications. Aim of study: The principal aim of the theoretical part is to elaborate a review of the drug related problems concerning the side effects and drug-drug interactiond of NSAIDs. The practical part analyses via a question-study the senior's opinion and experiences on self- medication by analgesics focusing on ibuprofen. Methods: A cross sectional study have been conducted in the city of Kharkov in Ukraine. The data have been collected during an interview with a questionnaire. The used questionnairre has...
48

Analýza postojů seniorů na samoléčení analgetiky se zaměřením na nesteroidní antiflogistika II / The Analysis of Senior's Opinions on Self-treatment by non-steroidal anti-inflamatory drugs I

Čižmárová, Jana January 2020 (has links)
The Analysis of Senior's Opinions on Self-treatment by non-steroidal anti-inflammatory drugs II Author: Jana Čižmárová Supervisor of the thesis: PharmDr. Martin Doseděl, Ph.D. Department: Department of Social and Clinical Pharmacy Background: Self-medication is a growing trend in a society with widespread use of over- the-counter medicines. Among the OTC medicines, analgesics belong to the drugs with the highest consumption. They are also popular in the group of seniors, who often suffer from chronic pain, mainly of the musculoskeletal system. Aim of study: In the theoretical part to carry out a review of published papers concerning safety of self-medication with analgesics and non-steroidal anti-inflammatory drugs. In the practical part, by performing a questionnaire survey to acquire and analyze the attitudes of seniors regarding self-medication with analgesics and anti-inflammatory drugs focused on ibuprofen. Methods: An observational cross-sectional study was carried out in the facilities for seniors of the Trenčín region. The survey was conducted by interview with senior using questionnaire sheets. The research took place in the period July to September 2019. Results: 64.0 % of seniors suffered from almost every day or daily pain, mainly from musculoskeletal pain. The main counselling subject...
49

Analýza postojů seniorů na samoléčení analgetiky se zaměřením na nesteroidní antiflogistika III / The Analysis of Senior's Opinions on Self-treatment by non-steroidal anti-inflamatory drugs III

Procházka, Marek January 2020 (has links)
The Analysis of Seniors' Opinions on Self-treatment by Non-steroidal Anti-inflamatory Drugs III Charles University, Faculty of Pharmacy in Hradec Králové Department of: Social and Clinical Pharmacy Candidate: Marek Procházka Consultant: PharmDr.Martin Doseděl, Ph.D. Background: Self-treatment is one of the approaches in managing pain which is still gaining higher level of importance even amongst seniors. One of the most favourite over the counter (OTC) analgesics is ibuprofen, however its use can be associated with certain drug related problems (DRP). The potential of DRPs is increasing with age which makes seniors more sensitive to them. Aim of study: 1) To create an overview of DRPs of OTC analgesics, focusing on paracetamol (acetaminophen). 2) Through the survey find out the knowledge and experience of seniors with self-treatment by OTC analgesics. The other aim was to evaluate their sources of information concerning ibuprofen and their preferences to each product. Methods: The observable cross-sectional study was made through social media and in Královéhradecký region. In the first case the questionnaire was spread through social media- Facebook. In the second case standardised conversation with questionnaire lists was applied with seniors above 60 years of age. The research was anonymous and...
50

The analgesic efficacy and therapeutic onset of analgesia of intravenous and intramuscular ketorolac (15 mg and 30 mg), and oral ibuprofen 800 mg in the emergency room : a comparative study

Habib, Mohdhar Jeilan 01 January 1998 (has links)
A randomized, prospective, parallel, double-blind, double-dummy clinical trial was conducted to determine the analgesic efficacy and time to onset of analgesia following intravenous and intramuscular administration of ketorolac (15 and 30 mg), and oral ibuprofen 800 mg. A random sample of 100 patients aged 18 to 65, with acute musculoskeletal pain, were enrolled from the University of California Davis Medical Center, Emergency Department. Patients were categorized into five equal groups and received, either ketorolac 30 mg (IV or IM), ketorolac 15 mg (IV or IM) or ibuprofen 800 mg (PO) tablet as medication medication. Pain intensity was evaluated with a 100-mm visual analog scale at baseline and 5, 10, 15, 30, 45, 60, 120, 180, and 240 minutes after dosing. A verbal rating scale, consisting of five rankings was also used to evaluate pain intensity and pain relief. The time to onset of analgesia was defined as the time at which pain intensity score reached 25% and 50% of the baseline score in 25% and 50% of the patients. The prevalence of side effects was elicited in each patient. Patients who received ketorolac (30 mg IV) showed a greater decrease in pain intensity compared with patients in all other groups (p < 0.005). Ketorolac (30 mg IV) provided greater pain relief compared with patients receiving ketorolac (15 mg IV), ketorolac (15 mg IM) or ibuprofen 800 mg (p < 0.011). Fifty percent pain relief before the end of the study was achieved by 50% of patients in one group only- ketorolac (30 rng IV). Ketorolac (30 mg IV) was found to have a quicker time to onset of action compared to ibuprofen 800 mg (p = 0.025) and ketorolac (15 mg IV) (p < 0.001). When the criterion of 25% pain relief for 25% of the patients was used, ketorolac (30 mg IV) was found to have a quicker time to onset of action compared with all other groups (p < 0.025). Thus, ketorolac (30 mg IV) provided a greater degree of pain relief and a quicker time to onset of analgesia than all other groups, presenting with acute musculoskeletal pain. Ketorolac (30 mg IM), ketorolac (15 mg IM), ketorolac (15 mg IV) and ibuprofen 800 mg provided comparable analgesia.

Page generated in 0.0467 seconds