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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.
101

Účinnost odstranění vybraných léčiv z vody různými sorpčními materiály / Removal efficiency of selected drugs by various sorptive materials from water

Štofko, Jakub January 2019 (has links)
This thesis deals with sorption of selected drugs from model water by various sorption materials. Contamination of water resources by the pharmaceutical industry is a major problem today. Wastewater treatment plants, whose technological processes are unable to completely remove them, have a significant share in the penetration of these substances into the environment. At present, attention is paid to alternative materials that are capable of eliminating these substances. One of the potential sorption materials is biochar as one of the main pyrolysis products. This work focused on the assessment of the sorption properties of the different types of biochar and commercially used active charcoal. The sorption properties of the individual materials were compared with respect to the non-steroidal anti-inflammatory substance ibuprofen and the sulphonamide antibiotic sulfamethoxazole. The results of vial experiments were analysed on a liquid chromatograph with mass detection.
102

Studium abiotického stresu u rostlin na úrovni proteomu / The proteomic study of abiotic stress of plants.

Barabášová, Kamila January 2011 (has links)
Keywords: Arabidopsis thaliana, phytoremediation, abiotic stress, ibuprofene, doxorubicin, two-dimensional electrophoresis Nowadays, develop of the pharmaceutical industry is very fast. Reason of this trend is ever-increasing number of diseases, lifestyle and still increasing demand for the drugs. With this trend growing interest in the analysis of the residues of pharmaceuticals in the environment which is result of incomplete wastewater treatment. This diploma thesis is studying effect of cytostatic drugs, specifically doxorubicin and one of the most widely used analgesics - ibuprofen, at the proteome level of the model plant Arabidopsis thaliana. Proteins isolated from plants exposed to the drugs were separated by two-dimensional electrophoresis. Comparing of protein maps by PDQest program (Bio-Rad, USA) was found several proteins whose expression was affected by the presence of drugs in the culture medium. Selected proteins were identified by LC - MS / MS.
103

Biopharmaceutic and Pharmacokinetic Studies of Sucrose Acetate Isobutyrate as an Excipient for Oral Drug Delivery.

Tant, Martin Ray 17 August 2011 (has links) (PDF)
Sucrose acetate isobutyrate (SAIB), a randomly substituted sucrose approximating sucrose diacetate hexaisobutyrate, is produced by Eastman Chemical Company for a variety of applications. SAIB is widely used in the food industry as a weighting agent to disperse flavoring oils in primarily citrus-based soft drink beverages. Additionally, SAIB is currently being marketed by another company as a parenteral drug delivery system. The studies reported here focused on investigating SAIB as an excipient, or delivery vehicle, for use in oral delivery of several drugs, including ibuprofen, saquinavir, and clarithromycin. Dissolution experiments were conducted using both ibuprofen and caffeine, and results suggest that SAIB can be used in dosage forms to control release rate. Pharmacokinetic studies in which laboratory rats were dosed with formulations containing drugs such as ibuprofen, saquinavir, and clarithromycin suggest that SAIB may act to reduce animal-to-animal variability in drug concentration profiles in some cases, and that it may also enhance gastroretention of the dosage forms. Finally, dosage form imaging studies suggest but do not reliably confirm that SAIB may aid in promoting gastric retention, which would make its use in dosage form formulation beneficial for administration of drugs whose action is intended to occur in the stomach.
104

Monitoring Commercials Ibuprofen Potency Changes Over 1 Year When Stored in a Household Setting

Archibald, Timothy, Brown, Stacy D. 01 February 2020 (has links)
Background: Most over-the-counter medications are labeled for storage in a dry, room temperature environment. Despite this, many households store medications in the bathroom, where temperature and humidity extremes may be experienced.Objective:In this project, we sought to investigate the effect that long-term storage in a household bathroom had on potency of over-the-counter ibuprofen (IBU) products as well as on the emergence of a known toxic degradation product, 4-isobutylacetophenone (4-IBP). Methods:A liquid chromatography-tandem mass spectrometry method was developed for the quantitative determination of IBU and 4-IBP in aqueous samples. Three brands each of IBU tablets (200 mg) and suspensions (100 mg/5 mL) were assayed for IBU concentration at the initiation of the study and once monthly thereafter. The samples were stored in a household bathroom, with continuous temperature and humidity monitoring. Each sample was assayed in triplicate and percent recovery was calculated against freshly prepared standards of IBU using bulk powder.Results:Tablets maintained >90% average strength through 3 months, with statistically significant deviation from initial concentration (2-way analysis of variance, P = .05) detected after 6 to 7 months. Suspensions maintained >90% average strength through 5 months, with statistically significant changes from initial concentration emerging after 7 months. After 12 months, the average strength was 73% and 83% for tablets and suspensions, respectively. 4-IBP was not detected in any of the samples during the duration of the study.Conclusions:These data indicate that, while 4-IBP was not detected following 12-month bathroom storage of commercial IBU products, significant changes in potency should negatively affect efficacy.
105

One year monitoring of potency change in commercial ibuprofen products stored in a household setting exposed to normal day-to-day temperature and humidity fluctuations

Archibald, Timothy, Brown, Stacy 12 April 2019 (has links)
Introduction.Most over the counter (OTC) medications are labeled for storage in a room temperature environment (68 – 77oF) under dry conditions, i.e. kept away from moisture. Despite this, many households store medications in the bathroom, where both temperature and humidity extremes may be experienced during the course of the day. In this project, we sought to investigate the effect that long-term storage in a household bathroom had on potency of OTC ibuprofen (IBU) products. One degradation product, 4-isobutylacetophenone (4-IBP), has been shown to possess toxic properties. As such, the emergence of this breakdown product was also monitored. Methods. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the quantitative determination of IBU and 4-IBP in aqueous samples. The assay utilized a UCT C18 column (2.1 x 100 mm; 1.8 micron) with acetonitrile as the organic phase and water as the aqueous phase, run in isocratic mode (15% A: 85% B). Ibuprofen was ionized in negative electrospray mode (-ESI) using m/z 205.09 and 4-IBU in +ESI mode at m/z 177.15. Calibration curves were created in the ranges of 0.1 – 2 mg/mL (IBU) and 2 – 100 mg/mL. Three brands each of IBU tablets (200mg) and suspensions (100mg/5mL) were purchased and assayed for IBU concentration at the initiation of the study. The samples were stored in a household bathroom, while temperature and humidity were continuously recorded using Extech Instruments RHT10 data-logger. Three tablets were removed from each bottle, and three 5-mL aliquots were removed from each suspension, for analysis each month. The samples were digested in 0.1M HCl for 1hr using sonication, and diluted to assay concentration (2 mg/mL for tablets; 0.2 mg/mL for suspensions) using acetonitrile. Each sample was assayed in triplicate and percent recovery was calculated against freshly prepared standards of IBU. Results. Acceptable potency range was defined as 90 – 110% of the labeled concentration. All tablets maintained acceptable average strength through three months, and a statistically significant change from initial concentration (as determined by a 2-way ANOVA, p = 0.05) was detected after 6 – 7 months. After ten months of storage, the average tablet strength was 74% of initial potency. All suspensions maintained acceptable average strength through five months, with statistically significant changes from initial concentration emerging after seven months storage. After 10 months of storage, the average suspension strength was 84% of initial potency. During the duration of the study, the average storage temperature was (20.9° C) and the average relative humidity was (65.7). The 4-IBU was not detected in any of the product samples during the duration of the study. Conclusions.These data indicate that, while the toxic degradation product, 4-IBU, has not been detected following bathroom storage of commercial IBU products, significant changes in product potency can negatively affect product efficacy. The container-closure systems used in OTC ibuprofen products do not protect against the effects of ongoing fluctuations in environmental temperature and humidity. Data indicate that suspension products are more resistant to temperature and humidity fluctuations, at least to the degree that would be present in a household bathroom.
106

Effect of Ibuprofen on the growth of Pseudokirchneriella subcapitata

Flos Berga, Mario January 2022 (has links)
Pharmaceuticals are an important class of pollutants in aquatic ecosystems. Detected concentration are typically in the range 1 ng/L – 1 μg/L. Traditional wastewater treatment does not provide a complete removal of these contaminants; hence, they may have a negative impact on the environment. In addition, microalgae are an ecologically-meaningful target group of species for bioindication purposes as well as primary production and oxygen supply. The present work aimed to investigate the effect of Ibuprofen on the green alga Pseudokirchneriella subcapitata. Algal cultures were exposed to five different concentrations of the drug (5, 15, 45, 135, 405 mg/L) for four days. Absorbance measured at 680 nm was determined every day and obtained data were transformed into cell concentration (cells/mL) by a previously prepared calibration curve. Specific growth rate, generation time, percent inhibition and effective concentration were calculated. Moreover, one way ANOVA with Tukey’s test were applied to observe differences between groups and time periods. Based on this study, all the cultures treated with Ibuprofen had a growth inhibition as well as presenting a lag phase. Increasing the Non-Steroidal Anti-Inflammatory drug (NSAID) concentration reduced the growth rate and consequently, increased the percent inhibition in a concentration-dependent manner. According to this report, new research should be focused on the development of hybrid systems for degradation and removal of pharmaceuticals. NSAID pollution may lead to a reduction in the diversity and number of functional groups of eukaryotic algae. Finally, more research should be devoted to the toxicity of drugs in a variety of test organisms and development of reliable methods for toxicity test at low and chronic exposures to achieve more realistic conclusions.
107

Pharmaceutical Co-crystals. Combining thermal microscopy and phase space considerations to facilitate the growth of novel phases.

Berry, David J. January 2009 (has links)
The crystalline solid state is invaluable to both the pharmaceutical and fine chemical sectors. The advantages primarily relate to reducibility criteria required during processing of stable solid state materials and delivering purification, which is inherently performed by the crystal growth process. A major challenge is achieving control through crystallising solids with the desired physico-chemical properties. If this can be achieved the crystalline solid is of great financial and practical benefit. One emerging methodology for manipulating the solid crystalline form is the application of co-crystals. This work relates to key steps in the understanding of rational design of co-crystals utilizing crystal engineering concepts to determine systems before then applying screening criteria to the selected sub-set. Co-crystal screening is routinely undertaken using high-throughput solution growth. We report a low- to medium-throughput approach, encompassing both a melt and solution crystallization step as a route to the identification of co-crystals. Prior to solution studies, a melt growth step was included utilizing the Kofler mixed fusion method. This method allowed elucidation of the thermodynamic landscape within the binary phase diagram and was found to increase overall screening efficiency. This led to the discovery of a number of co-crystal systems with the co-former nicotinamide, with the single crystal structures determined for the following systems; R/S ibuprofen: nicotinamide, S ibuprofen: nicotinamide, R/S flurbiprofen: nicotinamide and salicylic acid: nicotinamide. To assess the crystallization and phase behaviours of determined co-crystals the R/S ibuprofennicotinamide system was selected and successful studies were undertaken determining the aqueous ternary phase behavior and the pre-nucleation speciation in methanol. There have, as yet, been a limited number of published examples which are concerned with pharmaceutical property enhancement by co-crystals, as vast proportion of the literature concerns the growth and isolation of these novel phases. To elucidate further the pharmaceutical relevance of co-crystals the properties of the R/S ibuprofen- nicotinamide system were then assessed showing a positive profile for this material. / AstraZeneca and the University of Bradford / The accompanying "Experimental raw data files and cifs" are not available online.
108

The use of solubility parameters to predict the behaviour of a co-crystalline drug dispersed in a polymeric vehicle. Approaches to the prediction of the interactions of co-crystals and their components with hypromellose acetate succinate and the characterization of that interaction using crystallographic, microscopic, thermal, and vibrational analysis.

Isreb, Abdullah January 2012 (has links)
Dispersing co-crystals in a polymeric carrier may improve their physicochemical properties such as dissolution rate and solubility. Additionally co-crystal stability may be enhanced. However, such dispersions have been little investigated to date. This study focuses on the feasibility of dispersing co-crystals in a polymeric carrier and theoretical calculations to predict their stability. Acetone/chloroform, ethanol/water, and acetonitrile were used to load and grow co-crystals in a HPMCAS film. Caffeine-malonic acid and ibuprofennicotinamide co-crystals were prepared using solvent evaporation method. The interactions between each of the co-crystals components and their mixtures with the polymer were studied. A solvent evaporation approach was used to incorporate each compound, a mixture, and co-crystals into HPMCAS films. Differential scanning calorimetry data revealed a higher affinity of the polymer to acidic compounds than their basic counterparts as noticed by the depression of the glass transition temperature (Tg). Moreover, the same drug loading produced films with different Tgs when different solvents were used. Solubility parameter values (SP) of the solvents were employed to predict that effect on the depression of polymer Tg with relative success. SP values were more successful in predicting the preferential affinity of two acidic compounds to interact with the polymer. This was confirmed using binary mixtures of naproxen, flurbiprofen, malonic acid, and ibuprofen. On the other hand, dispersing basic compounds such as caffeine or nicotinamide with malonic acid in HPMCAS film revealed the growth of co-crystals. A dissolution study showed that the average release of caffeine from films containing caffeine-malonic acid was not significantly different to that of films containing similar caffeine concentration. The stability of the caffeine-malonic acid co-crystals in HPMC-AS was prolonged to 8 weeks at 95% relative humidity and 45°C. The theory developed in this project, that an acidic drug with a SP value closer to the polymer will dominate the interaction process and prevent the majority of the other material from interacting with the polymer, may have utility in designing co-crystal systems in polymeric vehicles
109

Preparation and stability of organic nanocrystals. Experimental and molecular simulation studies.

Khan, Shahzeb January 2012 (has links)
A major challenge affecting the likelihood of a new drug reaching the market is poor oral bioavailability derived from low aqueous solubility. Nanocrystals are rapidly becoming a platform technology to address poor solubility issues, although several challenges including stabilisation and control of particle size distribution for nanosuspensions still need to be addressed. The aim of this study was to revisit the simplest approach of re-precipitation and to identify the critical parameters, including the effect of different stabilisers as well as process conditions. We utilised a combined approach of both experiments and molecular modelling and simulation, not only to determine the optimum parameters but also to gain mechanistic insight. The experimental studies utilised three rather distinct, relatively insoluble drugs, the hypoglycaemic glibenclamide, the anti-inflammatory ibuprofen, and the anti-malarial artemisinin. The choice of crystal growth inhibitors/stabilizers was found to be critical and specific for each drug. The effect of the process variables, temperature, stirring rate, and the solute solution infusion rate into the anti-solvent, was rationalized in terms of how these factors influence the local supersaturation attained at the earliest stages of precipitation. Coarse grained simulation of antisolvent crystallisation confirmed the accepted two step mechanism of nucleation at high supersaturation which involves aggregation of solute particles followed by nucleation. Recovery of nanocrystals from nanosuspensions is also a technical challenge. A novel approach involving the use of carrier particles to recovery the nanocrystals was developed and shown to be able to recover more than 90% of the drug nanocrystals. The phase stability of nanocrystals along with bulk crystals for the model compound glycine was explored using molecular dynamics simulation. The simulations were consistent with experimental data, a highlight being the ¿ phase transforming to the ¿ phase at temperature >400K and 20kbar respectively, as expected. Nanocrystals of ¿, ¿ and ¿ glycine, however did not show any phase transformation at high temperature. In summary the study demonstrates that standard crystallization technology is effective in producing nanocrystals with the primary challenge being physico-chemical (rather than mechanical), involving the identification of molecule-specific crystal growth inhibitors and/or stabilizers. The developed nanocrystal recovery method should enable the production of nanocrystals-based solid dosage forms. The molecular simulation studies reveal that crystal-crystal phase transformations can be predicted for hydrogen-bonded systems. / HEC Pakistan and University of Malakand KP (Khyber Pakhtunkhwa)
110

Genoprotective effect of aspirin and ibuprofen in human lymphocyte cells. Effect of nano and bulk forms of aspirin and ibuprofen on lymphocytes from breast cancer patients compared with those from healthy females

Dandah, Osama M.M. January 2017 (has links)
ABSTRACT: Various recent studies have suggested that regular intake of some non-steroidal anti-inflammatory drugs (NSAIDs) have a preventative effect against several types of tumours including breast cancer. The term nanotechnology refers to technology in which one-billionth of a meter is used as a scale for chemical particle size. This work aims to study the effect of both ibuprofen and aspirin on DNA damage using peripheral blood lymphocytes from breast cancer patients and comparing the results with those from healthy females as a control using the Comet and micronucleus assays. Western blot analysis (WBA) was used to investigate the effect of these drugs on XRCC3 and p53 proteins, whereas QPCR was to evaluate this effect on p53, cox1 and cox2 genes. Two hundred fifty ng/ml of ibuprofen (NP and bulk) and 500 ng/ml of aspirin (NP and bulk) were used to treat the lymphocytes. Both aspirin and ibuprofen caused a reduction in DNA damage and micronucleus formation. Aspirin, both forms, showed a reduction in DNA damage in the Comet and micronucleus assays. Ibuprofen both forms, by contrast, showed a statistically significant reduction in micronucleus frequency in the micronucleus assay, while its preventative effect with the Comet assay was weak or insignificant. NPs of both agents were more effective than bulk sizes. Using the Comet repair assay, aspirin and ibuprofen nano form catalysed DNA repair to a greater extent than their bulk forms. Also, both sizes showed better repair with NSAIDs compared to samples repaired without NSAIDs. In WBA aspirin increased the expression of XRCC3 protein in healthy cells. However, both NSAIDs decreased that expression in cells from BC patients. Furthermore, aspirin increased p53 expression in BC patients lymphocytes. With the QPCR method, results of both aspirin forms increased the expression of the p53 gene in BC patient cells statistically significantly. Both drugs reduced cox1 expression in healthy volunteers and cancer patients lymphocytes. Moreover, cox2 reduction was only in lymphocytes from BC patients. The results of this work are consistent with the view that NSAIDs, particularly aspirin and ibuprofen, could have a promising role in cancer treatment including breast cancer. / Various recent studies have suggested that regular intake of some non-steroidal anti-inflammatory drugs (NSAIDs) have a preventative effect against several types of tumours including breast cancer. The term nanotechnology refers to technology in which one-billionth of a meter is used as a scale for chemical particle size. This work aims to study the effect of both ibuprofen and aspirin on DNA damage using peripheral blood lymphocytes from breast cancer patients and comparing the results with those from healthy females as a control using the Comet and micronucleus assays. Western blot analysis (WBA) was used to investigate the effect of these drugs on XRCC3 and p53 proteins, whereas QPCR was to evaluate this effect on p53, cox1 and cox2 genes. Two hundred fifty ng/ml of ibuprofen (NP and bulk) and 500 ng/ml of aspirin (NP and bulk) were used to treat the lymphocytes. Both aspirin and ibuprofen caused a reduction in DNA damage and micronucleus formation. Aspirin, both forms, showed a reduction in DNA damage in the Comet and micronucleus assays. Ibuprofen both forms, by contrast, showed a statistically significant reduction in micronucleus frequency in the micronucleus assay, while its preventative effect with the Comet assay was weak or insignificant. NPs of both agents were more effective than bulk sizes. Using the Comet repair assay, aspirin and ibuprofen nano form catalysed DNA repair to a greater extent than their bulk forms. Also, both sizes showed better repair with NSAIDs compared to samples repaired without NSAIDs. In WBA aspirin increased the expression of XRCC3 protein in healthy cells. However, both NSAIDs decreased that expression in cells from BC patients. Furthermore, aspirin increased p53 expression in BC patients lymphocytes. With the QPCR method, results of both aspirin forms increased the expression of the p53 gene in BC patient cells statistically significantly. Both drugs reduced cox1 expression in healthy volunteers and cancer patients lymphocytes. Moreover, cox2 reduction was only in lymphocytes from BC patients. The results of this work are consistent with the view that NSAIDs, particularly aspirin and ibuprofen, could have a promising role in cancer treatment including breast cancer. / Libyan Government

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