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The initial research of this thesis involves the evaluation of different strategies for developing diverse chemistries of highly stable coatings for the automated 96-blade (thin-film) solid phase microextraction (SPME) system. Thin-film geometry increases the volume of extractive phase, and consequently improves the sensitivity of the analysis. Sol-gel technology was used for the preparation of octadecyl (C18)-silica gel thin-film coating. The evaluation of the C18-silica gel SPME extractive phase resulted in stable physical and chemical characteristics and long-term reusability with a high degree of reproducibility. Biocompatible polyacrylonitrile (PAN) polymer was used for the preparation of particle-based extractive phases in order to improve the biocompatible characteristics of SPME coatings for the extraction from biological samples. Three different immobilization strategies were evaluated for developing highly stable coatings for the automated 96-blade SPME system. The spraying was found to be the optimal method in terms of stability and reusability for long-term use. The optimized C18-PAN coating demonstrated improved biocompatibility, stability, and reusability for the extraction of benzodiazepines from human plasma in comparison with those of C18-silica gel coating. To improve the biocompatible properties of the C18-PAN SPME coating for long-term direct analysis from whole blood, different modification strategies were studied and evaluated. The modification of the coating with an extra layer of biocompatible polyacrylonitrile resulted in significant improvement in the blood compatibility in long-term use. ‘Extracted blood spot’ (EBS) sampling was introduced as a novel approach to overcome the limitations of dried blood spot sampling. EBS includes the application of a biocompatible SPME coating for spot sampling of blood or other biofluids. The compatibility of EBS sampling with different analytical methods was demonstrated. The utilization of EBS as a fast sampling and sample preparation method resulted in a significant reduction of matrix effects through efficient sample clean-up. Modified polystyrene-divinylbenzene (PS-DVB)-PAN and phenylboronic acid (PBA)-PAN 96-blade SPME coatings were developed and evaluated for the extraction of analytes in a wide range of polarity. These coatings demonstrated efficient extraction recovery for both polar and non-polar groups of compounds, and presented chemical and mechanical stabilities and reproducible extraction efficiencies for more than 100 usages in biological sample.

Assessment of gastrointestinal permeability in vivo is considered a suitable method for the evaluation of gastrointestinal mucosal integrity. Probes commonly used include lactulose (L) and rhamnose (R) for the assessment of intestinal permeability, xylose (X) and 3-O-methylglucose (M) for the evaluation of intestinal absorptive capacity, and sucrose (S) for the assessment of gastric permeability. Traditionally, various methods have been used to quantify these markers in the urine after orogastric administration. However, urine collection is difficult and uncomfortable. A protocol based on the analysis of blood samples would be easier to perform. Thus, the aim of the first part of this project was to develop and validate a new gas chromatography-mass spectrometry (GC-MS) method for the quantification of five sugar probes in canine serum. The method was sensitive, accurate, precise, and reproducible for the simultaneous quantification of 5 sugar probes in serum. The aim of the second part of this project was to assess the kinetic profiles of these 5 sugar probes in serum after orogastric administration in dogs and to determine the optimal time point for sample collection. Dogs received a solution containing L (10 g/L), R (10 g/L), X (10 g/L), M (5 g/L), and S (40 g/L) by orogastric intubation. Baseline blood samples were collected. Subsequent timed blood samples were taken for a 24 hours period. Significant changes in serum concentrations of all 5 sugars were detected after administration of the test dose (p<0.0001 for all 5 probes). Serum concentrations of L and R were significantly different from baseline concentrations from 90 to 240 and from 60 to 300 min post dosing respectively, and those of X, M, and S were significantly different from 30 to 240 min after dosing (p<0.05 for all 5 probes). Variations of the mean sugar concentrations of all dogs at 90, 120, and 180 minutes were analyzed using a Kruskal-Wallis test. Based on the results, only two blood samples, one taken at baseline and a second sample obtained between 90 and 180 after dosing, appear to be sufficient for assessment of intestinal permeability and mucosal absorptive capacity using these sugar probes.

Asthma, current detection methods and metabolites proposed as asthma markers are described. The limitation of the disease diagnosis is outlined and metabolomics is introduced as the approach carried out within this research with the potential to measure the group metabolites that characterise the metabolic responses of a biological system to a specific disease. Chemistry underlying breathing, current breath collection and analytical techniques are described as well as detection and data processing technology associated within our research. A work-flow for the collection, analysis and processing of exhaled breath samples in respiratory diseases is described. The non-invasive sampling method allows collection of exhaled breath samples on children and adults without experiencing any discomfort. The analysis of exhaled breath samples using thermal desorption gas chromatography mass spectrometry outlines the use of retention index for the alignment of VOCs retention time shifting over time. This methodology enables the creation of a breath matrix for multivariate analysis data processing where each VOC is defined by retention index and most intense fragments of the mass spectrum. This methodology is tested in two cohorts of participants: paediatric asthma and severe asthmatic participants whose breath profiles are compared against healthy controls and within the two asthmatic phenotypes to prospect the markers that differentiate between the different groups. Eight candidate markers are identified to discriminate between asthmatic children and healthy children and seven markers between asthmatics undergoing therapy and healthy controls. The database from severe and paediatric asthma is compared, establishing seven non-age related markers between the two groups. A new interface is developed for the faster analysis of exhaled breath samples using thermal desorption ion mobility mass spectrometry. The interface front end has been modified and optimised to achieve the best sensitivity and resolution of VOCs in exhaled breath. A preliminary study carried out in a small cohort of volunteers shows the feasibility of the technique for the differentiation of asthmatic and healthy adults.

Tulathromycin is a macrolide antibiotic approved for use in cattle and swine respiratory disease. Extra-label use of tulathromycin occurs in bison and deer and significant interspecies differences in pharmacokinetics warrant specific investigation in these species. This study involved investigation of the pharmacokinetics of tulathromycin in bison and white-tailed deer following a single 2.5 mg/kg bw subcutaneous injection (n=10) of Draxxin (Pfizer Inc.) to provide important information regarding tulathromycin dosage regimens in these species. As well, tulathromycin distribution and depletion in deer muscle and lung tissues following a 2.5 mg/kg bw subcutaneous injection of Draxxin was investigated to obtain pilot information regarding withdrawal time of tulathromycin in deer. For the pharmacokinetic studies, serial blood samples were collected at baseline and up to 25 days post-injection. Pharmacokinetic parameters were estimated using non-compartmental methods. For the tissue pilot study, deer (n = 2 to 3) were slaughtered at 0, 1, 2, 6, 7, and 8 weeks post-injection. A quantitative analytical liquid chromatography-mass spectrometry method for measuring tulathromycin was developed and validated in bison and deer serum and deer lung and muscle according to international guidelines. Samples were processed by solid-phase extraction. Reverse-phase chromatography was performed by gradient elution. Positive electrospray ionization was used to detect the double charged ion [M+2H]+2 at m/z 403.9 and monitored in selected ion monitoring mode. Tulathromycin demonstrated early maximal serum concentrations, extensive distribution, and slow elimination characteristics in deer and bison. In bison, mean Cmax (195 ng/mL) was lower compared to cattle (300 to 500 ng/mL) and half-life (214 hours) longer (cattle, 90 to 110 hours). In deer, mean Cmax (359 ng/mL) is comparable to cattle, but half-life (281 hours) was much longer. Tissue distribution and clinical efficacy studies are needed in bison to confirm extensive distribution of tulathromycin into lung and the appropriate dosage regimen. Tulathromycin was extensively distributed to deer lung and muscle, with tissue levels peaking within 7 to 14 days after injection. Drug tissue concentrations were detected 56 days after treatment, longer than the established withdrawal time of 44 days in cattle. This prolonged drug concentration in the tissue is supportive for the administration of tulathromycin as a single injection therapy for treatment of respiratory disease of deer. While more study is needed to establish a recommended withdrawal time, the long serum and tissue drug half-life and extensive interindividual variability in tissue levels suggests a withdrawal period well beyond 56 days may be required in deer.

The initial research of this thesis involves the evaluation of different strategies for developing diverse chemistries of highly stable coatings for the automated 96-blade (thin-film) solid phase microextraction (SPME) system. Thin-film geometry increases the volume of extractive phase, and consequently improves the sensitivity of the analysis. Sol-gel technology was used for the preparation of octadecyl (C18)-silica gel thin-film coating. The evaluation of the C18-silica gel SPME extractive phase resulted in stable physical and chemical characteristics and long-term reusability with a high degree of reproducibility. Biocompatible polyacrylonitrile (PAN) polymer was used for the preparation of particle-based extractive phases in order to improve the biocompatible characteristics of SPME coatings for the extraction from biological samples. Three different immobilization strategies were evaluated for developing highly stable coatings for the automated 96-blade SPME system. The spraying was found to be the optimal method in terms of stability and reusability for long-term use. The optimized C18-PAN coating demonstrated improved biocompatibility, stability, and reusability for the extraction of benzodiazepines from human plasma in comparison with those of C18-silica gel coating. To improve the biocompatible properties of the C18-PAN SPME coating for long-term direct analysis from whole blood, different modification strategies were studied and evaluated. The modification of the coating with an extra layer of biocompatible polyacrylonitrile resulted in significant improvement in the blood compatibility in long-term use. ‘Extracted blood spot’ (EBS) sampling was introduced as a novel approach to overcome the limitations of dried blood spot sampling. EBS includes the application of a biocompatible SPME coating for spot sampling of blood or other biofluids. The compatibility of EBS sampling with different analytical methods was demonstrated. The utilization of EBS as a fast sampling and sample preparation method resulted in a significant reduction of matrix effects through efficient sample clean-up. Modified polystyrene-divinylbenzene (PS-DVB)-PAN and phenylboronic acid (PBA)-PAN 96-blade SPME coatings were developed and evaluated for the extraction of analytes in a wide range of polarity. These coatings demonstrated efficient extraction recovery for both polar and non-polar groups of compounds, and presented chemical and mechanical stabilities and reproducible extraction efficiencies for more than 100 usages in biological sample.

Thesis (Ph.D.)--Tufts University, 2000. / Submitted to the Dept. of Chemistry. Adviser: Albert Robbat, Jr. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (Ph. D.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed April 23, 2008) Includes bibliographical references.

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 15, 2008) Vita. Includes bibliographical references.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 5 uppsatser.