No description available.

Thesis (Ph. D.)--Washington State University, December 2007. / Includes bibliographical references.

The production and distribution of counterfeit drugs is a critical health problem that plagues nations worldwide. The presence of counterfeit antimalarials has become especially worrying, as these drugs are most often needed by those living in nations whose resources to verify the medicine supply are lacking. Rapid analysis methods used for screening large quantities of poor quality antimalarials are critical in the battle to protect those in less developed regions of the world. Simple, cost effective analysis methods that can be used in the field must be developed so those whose governments cannot afford to maintain medicine regulatory agencies can still have faith in their medicinal supply. A very powerful screening method, Direct Analysis in Real Time Mass Spectrometry (DART-MS) has been used to investigate thousands of poor quality medicines. This method, however, is known to fragment molecules more readily than commonly used, 'softer' ionization methods, such as electrospray ionization. Excess fragmentation in 'harder' ionization sources is due to deposition of additional internal energy to the ionized molecules. This internal energy deposition can be measured, so the analyst can be knowledgeable as to what to expect when examining unknowns using this recently developed ionization source. Quantitation of the active pharmaceutical ingredient (API) in pharmaceuticals is crucial to the determination of what class a poor quality medicine fits into. Because poor quality drugs can be of different types, it is important to accurately classify them, in hopes of improving the supply of medicines available to those in less developed regions of the world. High performance liquid chromatography (HPLC) is most commonly used to quantify the active pharmaceutical ingredient in poor quality medicines, however, this method is time consuming, preventing its use in high throughput settings. During the course of my research, hundreds of poor quality pharmaceuticals were analyzed using DART-MS. The active pharmaceutical ingredient was detected during the rapid screening for many of these drugs, however, a more in depth analysis would often reveal less than the expected quantity of active ingredient. A rapid non-chromatographic quantitation method was developed using a mass spectrometer as the detector. This method allows for both quantitative and qualitative information regarding a specific sample to be obtained simultaneously, saving the analyst time and resources. Utilizing this non- chromatographic mass spectrometric method, degradation products have been identified, thus increasing our ability to classify drugs into their respective divisions.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references (leaves 112-120). Also available in electronic version.

Thesis (Ph. D.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

Made available in DSpace on 2014-10-09T12:26:13Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:32Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP / FAPESP:05/58301-0

Made available in DSpace on 2014-10-09T12:26:13Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:32Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A análise de tintas e papéis é de grande interesse para a ciência e a interação tinta-papel é importante em vários níveis. A análise da tinta de um documento é extremamente importante para o estudo de diferentes aspectos, como adulterações e determinação da recentidade. Esses aspectos podem ser estudados analisando a tinta e o papel tanto fisicamente quanto quimicamente. Portanto, o desenvolvimento de uma técnica para a análise de tintas de caneta esferográfica e a determinação da recentidade de um documento é interessante para a Ciência Forense. No Brasil, cientistas forenses enfrentam todos os dias diversos casos que requerem a análise de tintas de caneta esferográfica, e não se tem nenhuma técnica onde a determinação da idade de uma tinta é possível. Os casos mais comuns onde há a necessidade da recentidade de um documento são fraudes em recibos de pagamento e de quitação de dívidas, preenchimento e assinatura de contratos, adulteração em documentos e em cheques. Neste trabalho, é discutida uma nova metodologia para a análise de tintas de canetas esferográficas e a sua utilização na determinação da recentidade de uma amostra de tinta de caneta esferográfica. Foram analisadas periodicamente amostras provenientes de diferentes países, como Estados Unidos, Canadá, Peru, Japão, Espanha e Grécia. Com os resultados obtidos, foram construídas curvas de degradação do solvente em função do tempo de preparo. Com as curvas, obtiveram-se as equações logarítmicas relativas. As equações propostas mostraram ser capazes de distinguir a idade relativa de uma tinta, com 20% de variação em relação ao valor teórico. Portanto, a principal conclusão deste trabalho é a metodologia proposta pode ser utilizada para determinar a idade relativa de uma tinta de caneta esferográfica. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP / FAPESP:05/58301-0

<p>  </p> <p>Miniature mass spectrometers are in a phase of rapid development due to their potential in offering simple yet powerful solutions for a wide variety of unmet biomedical needs. In particular, the combination of ambient ionization methods with miniature mass spectrometers offers an attractive solution for improving patient outcomes and reducing the healthcare burden on patients as well as clinicians opposed to current methods for disease prognosis and diagnosis. </p> <p>There has been a rapid expansion in the commercial offerings of miniature mass spectrometers from commercial vendors, both large and small, including Purspec, Bayspec, MassTech, Waters, and Advion. Despite the large number of instruments that have been made available and the success of many of these systems with analysis of a broad range of biological matrices, much work remains to perform bioanalysis of complex molecules with concentrations that often lie in the ng/mL-µg/mL range. Miniaturization of mass spectrometers is accompanied by design simplifications in comparison to benchtop instruments, so that sacrifices are often made in terms of performance. The figure of merit that is compromised, of course, depends on the design of the instrument itself. Thus, in addition to a good understanding of the operation of the mass spectrometer, it is crucial that the ionization method for the analyte be chosen judiciously, and that the method is suitably optimized to be able to perform the measurements to obtain high quality data for trace analysis. </p> <p>The custom built Mini-12 miniature MS systems at Purdue University is one such miniature mass spectrometer that can be used for making on-site measurements. In this work, I have described my efforts to perform trace analysis of a range of molecules (tenofovir diphosphate, cabotegravir, rilpivirine, and phosphatidylethanol) relevant to HIV treatment and prevention with the Mini-12 system. Based on the most favorable set of conditions for developing a particular assay, method performance parameters are listed for each of the applications described. In all the above applications, the desired detection limits are met by adopting a broad range of strategies with the focus of keeping the method amenable to use at the point-of-care, i.e., ensuring that sample preparation is completed in <4 minutes. The proof-of-concept results obtained with the custom built Mini-12 mass spectrometer at Purdue University lays the groundwork to (i) encourage the introduction of miniature mass spectrometer-based assays for the molecules listed in a clinical setting and (ii) extend the use of miniature mass spectrometer-based assays for other therapeutic regimens that require longitudinal monitoring.</p>