The concentration of triclosan in antiseptics, disinfectants and preservatives in products exceeds the minimal lethal levels. Extensive use of triclosan and antibiotics results in bacterial resistance to their active ingredients. The precise relationship between use and resistance, however, has been challenging to define. The aim of the study was to identify and determine antibiotic resistance profiles of triclosan tolerant heterotrophic plate count bacteria isolates from sewage influent and effluent. R2 agar supplemented with triclosan was utilised to isolate the triclosan resistant bacteria. To determine the minimum inhibitory concentration (MIC), organisms were incubated for 24 hours at selected concentrations of triclosan. Polymerase chain reaction (PCR) amplification of the 16S rRNA region was done to identify isolates. An assay for cross resistance to various antibiotics was performed. Determination of enhanced resistance to antibiotics by adding antimicrobials to the medium will be performed by using three antibiotics. High performance liquid chromatography was conducted to quantified levels of triclosan persistent in sewage water. Forty-four isolates were resistant to levels of triclosan ranging from 0.25 mg/l to 0.5 mg/l. Minimum inhibitory concentration values of these isolates ranged from 0.125 mg/l to >1 mg/l of triclosan. 16S rDNA methods were used and five main genera namely, Bacillus, Pseudomonas, Enterococcus, Brevibacillus and Paenibacillus were identified. Cell wall targeting antibiotics showed more pronounced relation with the triclosan concentration. Relation to triclosan concentration is not as apparent with the antibiotic targeting protein synthesis. Combination of antimicrobials indicated that at certain triclosan concentrations synergism or antagonism is observed. The importance of applying the correct concentration and combination of antimicrobials is observed. Levels of triclosan were found throughout the sewage water. HPLC values indicated the presence of triclosan at post-grid removal and effluent of the WWTP. The triclosan concentrations decrease through the WWTP but small concentrations enter our water bodies. The presence of bacterial species that are resistant to high concentrations of triclosan and multiple antibiotics enter our natural water bodies and is cause for concern. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

The concentration of triclosan in antiseptics, disinfectants and preservatives in products exceeds the minimal lethal levels. Extensive use of triclosan and antibiotics results in bacterial resistance to their active ingredients. The precise relationship between use and resistance, however, has been challenging to define. The aim of the study was to identify and determine antibiotic resistance profiles of triclosan tolerant heterotrophic plate count bacteria isolates from sewage influent and effluent. R2 agar supplemented with triclosan was utilised to isolate the triclosan resistant bacteria. To determine the minimum inhibitory concentration (MIC), organisms were incubated for 24 hours at selected concentrations of triclosan. Polymerase chain reaction (PCR) amplification of the 16S rRNA region was done to identify isolates. An assay for cross resistance to various antibiotics was performed. Determination of enhanced resistance to antibiotics by adding antimicrobials to the medium will be performed by using three antibiotics. High performance liquid chromatography was conducted to quantified levels of triclosan persistent in sewage water. Forty-four isolates were resistant to levels of triclosan ranging from 0.25 mg/l to 0.5 mg/l. Minimum inhibitory concentration values of these isolates ranged from 0.125 mg/l to >1 mg/l of triclosan. 16S rDNA methods were used and five main genera namely, Bacillus, Pseudomonas, Enterococcus, Brevibacillus and Paenibacillus were identified. Cell wall targeting antibiotics showed more pronounced relation with the triclosan concentration. Relation to triclosan concentration is not as apparent with the antibiotic targeting protein synthesis. Combination of antimicrobials indicated that at certain triclosan concentrations synergism or antagonism is observed. The importance of applying the correct concentration and combination of antimicrobials is observed. Levels of triclosan were found throughout the sewage water. HPLC values indicated the presence of triclosan at post-grid removal and effluent of the WWTP. The triclosan concentrations decrease through the WWTP but small concentrations enter our water bodies. The presence of bacterial species that are resistant to high concentrations of triclosan and multiple antibiotics enter our natural water bodies and is cause for concern. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

This thesis describes the development of separate assays to measure coenzyme Q₁₀ (CoQ₁₀) and vitamin K. Coenzyme Q is essential for the mitochondrial electron transport chain, and vitamin K for the blood coagulation cascade. Vitamin K deficiency is associated with haemorrhagic disease of the new-born, and CoQ₁₀ deficiency with HMG-CoA-reductase inhibitor (statin) therapy and heart failure. Coenzyme Q and vitamin K are usually measured by HPLC, using electrochemical and ultraviolet, and electrochemical and fluorescence detection, respectively. For vitamin K1, the limit of detection achieved using fluorescence and electrochemical detection was 0.28 and 0.12 nmol/L, respectively. Sensitivity of fluorescence detection is improved by using protic solvents in the mobile phase, and platinum-black catalysed alcohol reduction. The lipophilicity and low endogenous concentrations of vitamin K1 hinder its measurement, and further work is required to produce a rapid, reliable and robust assay for its measurement in human plasma. The limits of detection achieved using fluorescence, ultraviolet and electrochemical detection to measure CoQ₁₀ were 29, 4.8, and 0.34 nmol/L, respectively. Plasma CoQ₁₀ is not stable during long term storage at -13 ℃, but at -80 ℃ it is stable for at least 18 months. The reference interval for plasma total CoQ₁₀ in the New Zealand population is 0.47 - 1.80 µmol/L. There is no clinical requirement for stratification of the reference interval according to gender. Coenzyme Q₁₀ in human plasma is homeostatically controlled, varying little over a two month interval in healthy young males. Coenzyme Q₁₀ supplements have significantly different bioavailability, with the median increase in plasma CoQ₁₀ ranging from 0.14 to 0.59 µmol/L for seven different supplement brands. There is a large inter-individual variation in CoQ₁₀ absorption, and hence plasma concentrations should be monitored during supplementation. A plateau in CoQ₁₀ absorption, from a single dose, at approximately 200 mg suggests that the maximum dose ingested at one time should be 200 mg or less. Q-Gel capsules containing 30 mg of CoQ₁₀ are twice as effective at raising blood CoQ₁₀ as 100 mg capsules. Plasma CoQ₁₀ in patients with chronic heart failure are significantly lowered by approximately 33% when these patients receive Atorvastatin for six weeks. The absolute decrease in CoQ₁₀ showed a significant correlation with worsening endothelial function (r = + 0.548, p = 0.011). Coenzyme Q₉ was shown to be present in human plasma with a reference interval of 8.8 - 47.0 nmol/L.

A series of studies on monomer to polymer conversion in adhesive systems was undertaken using micro-Raman spectroscopy. A database of micro-Raman spectra was compiled for identification of tooth tissues and materials. The degree of conversion was assessed as a function of time and light source. Linear and two-dimensional micro- Raman characterisations of the adhesive-dentine and resin-based composite-adhesivedentine interfaces were performed. The degree of monomer to polymer conversion of adhesive systems was correlated with the amount of eluted monomers obtained by highperformance liquid chromatography. The degree of conversion varied significantly depending on adhesive chemical composition, curing time and light source. It was impossible to specify one curing time applicable to all adhesive systems, due to differences in conversion kinetics. In general, conventional halogen light-curing units at twenty seconds curing time produced similar or higher degree of conversion in adhesive systems compared to high-power LED units at ten seconds. Significantly higher monomer conversion was found in the adhesive layer compared to the hybrid layer in both etch-and-rinse and self-etch systems. Etch-and-rinse adhesive systems formed thicker hybrid layers compared to self-etch systems. Micro-Raman spectroscopy gave a more precise indication of dentine demineralisation and adhesive penetration than scanning electron microscopy and indicated that the hybrid layer is a gradual transitional zone between the adhesive layer and un-affected dentine. The absolute amount and weight percent of eluted monomers varied in all tested adhesive systems. In most adhesive systems, more than 90% of eluted monomers were detected within the first one hour of immersion. Overall, no correlation was found between the degree of conversion and the amount of eluted monomers.

En el presente trabajo se cuantificó los niveles de fenoles, ácido hipúrico y ácido metilhipúrico en orina en noventa trabajadores que laboran en una fábrica de caucho en Lima metropolitana (distrito de ATE), quienes utilizan frecuentemente como solventes el benceno, tolueno y xileno. La cuantificación de fenoles totales, ácido hipúrico y ácido metilhipúrico fue realizada por el método espectrofotométrico UV-visible y la cuantificación de ácido hipúrico y ácido metilhipúrico por el método de cromatografía líquida en fase reversa con detector de ultravioleta respectivamente. Se encontraron niveles que no excedieron el límite máximo permitido de fenoles totales, ácido hipúrico y ácido metilhipúrico en orina. En la cuantificación de fenoles totales en orina el promedio fue de 42.73 mg/g de creatinina y la cuantificación de ácido hipúrico y ácido metilhipúrico en orina en esta misma muestra tuvo como promedio 0.75 g/g de creatinina y 0.45 g/g de creatinina respectivamente. Estos valores son indicadores de exposición tanto al benceno como tolueno u otros solventes orgánicos aromáticos, ya que los valores referenciales en orina son de 50 mg/ g creatinina para fenoles totales como indicador biológico del Benceno y de 1.6 g/g de creatinina y de 1.5 g/g de creatinina para Acido hipúrico y metilhipúrico como indicadores biológicos del Tolueno y Xileno respectivamente según la ACGIH (AMERICAN CONFERENCE OF GOVERNMENTAL INDUSTRIAL HYGIENISTS.) Los análisis toxicológicos se realizaron en el área de toxicología (LABTOX) del laboratorio clínico ¨Blufstein¨. / In this paper the levels of phenols and hippuric acid in urine and methylhippuric ninety workers at rubber factory in metropolitan Lima (district ATE), who often used as solvents benzene, toluene and xylene was quantified. Quantification of total phenols, and methylhippuric hippuric acid was conducted by UV-visible spectrophotometry and quantifying methylhippuric acid and hippuric acid by the method of reverse phase liquid chromatography with ultraviolet detector respectively. Levels did not exceed the maximum allowable limit of total phenols and hippuric acid in urine and methylhippuric were found. In quantification of total phenols in urine the average was 42.73 mg / g creatinine and quantification of hippuric acid and methylhippuric acid in urine in the same sample had an average of 0.75 g / g creatinine and 0.45 g / g creatinine respectively. These values are indicative of exposure to both benzene and toluene or other aromatic organic solvents as urine reference values are 50 mg / g creatinine for total phenols as a biological indicator of benzene and 1.6 g / g and creatinine 1.5 g / g creatinine for hippuric and methylhippuric as biological indicators of Toluene and Xylene acid respectively ACGIH (American Conference of Governmental Industrial Hygienists.) the toxicological analyzes were performed in the area of toxicology (LABTOX) Blufstein clinical laboratory. Keywords: Benzene, toluene, xylene, total phenol, hippuric acid, methylhippuric acid, UV-vis, spectrophotometry, HPLC

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Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

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In this thesis, the determination of AGT, sooner used as anticancer drug, especially for the treatment of breast cancer in postmenopausal women or for the treatment of prostate cancer, by high performance liquid chromatogramy with UV spectrophotometric detection (HPLC-UV) and electrochemical detection (HPLC-ED) on carbon paste electrodes (CPEs) was studied. CPEs were prepared from glassy carbon microspheres and different pasting liquids - routinely used mineral oil (CPE-MO) and less commonly used tricresylphosphate (CPE-TCP) and silicone oil (CPE-SO). The concentration dependences of AGT were measured by HPLC-UV with detection wavelength 242 nm, by HPLC-ED with a working potencial of +1,3 V for CPE-MO and + 1,1 V for CPE-TCP in mobile phase containing phosphate buffer (pH 4) and methanol 50:50 (v/v). The following limits of detection were achieved - 3,6. 10-7 mol.l-1 for UV spectrophotometric detection, 2,5. 10-7 mol.l-1 for electrochemical detection with CPE-MO and 9,7. 10-7 mol.l-1 for electrochemical detection with CPE-TCP. AGT was also determined in model samples of urine. With HPLC-UV it was not possible to detect AGT, because of the interferences of other compounds. With HPLC-ED on CPE-MO the limit of detection 5,2. 10-7 mol.l-1 AGT was achieved. KEY WORDS Aminoglutethimide HPLC with UV...

3 ABSTRACT Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of biophysics and physical chemistry Author: Magdaléna Pleváková Supervisor: Ing. Vladimír Kubíček, CSc. Thesis title: Determination of Lipophilicity of Drugs by HPLC In this thesis a RP-HPLC method for fast and reliable determination of lipophilicity was proposed and tested. Stationary phase was selected by using hydrophobic substraction model. Capacity factors of the chosen substances were initially measured on Zorbax ECLIPSE XDB C18 250x4,6 mm, 5µm column, which exhibits almost identical retention characteristics as the column used for this purpose until now. Then the capacity factors of the same substances were determined by using Zorbax ECLIPSE XDB-C18 50x4,6 mm, 1,8µm column that was selected to reduce retention times significantly. A group of newly synthesised drugs based on structure of pyrazine served as samples for the measurement. The reproducibility of the capacity factor values determined using both columns was compared and the independence of the capacity factor on the mobile phase flow was confirmed. The capacity factors of two homologous series and a group of benzimidazols were consequently determined on Zorbax ECLIPSE XDB-C18 50x4,6 mm, 1,8µm column using various compositions of mobile phases. Several...