Thesis (Ph. D.)--Florida State University, 2003. / Advisor: Dr. John G. Dorsey, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Aug. 24, 2004). Includes bibliographical references.

Thesis (Ph. D.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains xi, 152 p. : ill. (some col.) Vita. Includes abstract. Includes bibliographical references (p. 127-133).

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [140]-147).

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 205-214). Also available via the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaf 50). Also available on the Internet.

Thesis (Ph.D.) - University of Queensland, 1999. / Includes bibliography.

In this thesis, a miniaturised field asymmetric waveform ion mobility spectrometry (FAIMS) device is combined with mass spectrometry (MS), and liquid chromatography, for the development and application of bioanalytical methodologies. FAIMS is a highly orthogonal to MS and LC and has the potential to enhance both targeted and non-targeted bioanalytical applications. Chapter two demonstrates the capability of the FAIMS combined with mass spectrometry to reduce the complexity of the mass spectrum by separating species of different charge states and overlapping mass-to-charge ratios that are challenging to separate by MS. FAIMS selected transmission shows improvement in signal-to-noise ratios for low intensity species and enables visualisation of species undetectable without FAIMS. Chapter three describes the development of an LC-FAIMS-MS method for the rapid analysis of saliva for the identification of potential biomarkers as a result of oxidative stress. The combination of FAIMS showed a reduction in saliva matrix interferences resulting in improved discrimination and peak integration of two salivary oxypurine compounds in a rapid LC-FAIMS-MS method. Chapter four investigates the FAIMS separation of seven steroid metabolites with a range of cationic adducts, in order to develop a rapid screening LC-FAIMS-MS method for the determination of isobaric steroid metabolites in urine. LC-FAIMS-MS analysis of the steroid metabolites shows improved discrimination of co-eluting and isobaric steroid metabolites with improvements in signal-to-noise ratio with reductions in chemical noise, demonstrating the potential of combining FAIMS with LC-MS. Chapter five demonstrates the potential of FAIMS to increase peak capacity in non-targeted omics applications, by combining rapid compensation field scanning of the FAIMS with ultra-high performance LC-MS. The rapid scanning of the FAIMS allows acquisition of full scan FAIMS and MS nested data sets within the timescale of a UHPLC chromatographic peak, and is applied to the non-targeted profiling of human urine. Improvements in the number of features detected using LC-FAIMS-MS were as a result of reductions in chemical noise and separation of co-eluting isobaric species across the whole analytical space, demonstrating the potential of combining FAIMS with LC and MS.

Natural products or traditional medicine has been used for centuries to treat various ailments by mankind. The World Health Organization estimates that in recent times 80% of people in emerging economies rely on traditional medicine as their primary health care [1]. However, unlike pharmaceutical products which have methods in place for quantification of the active compounds traditional medicine still requires a lot of focus in this area. Moringa oleifera is one of those species that have been used traditionally to cure various ailments for centuries. Even though extensive phytochemical and pharmacological studies have been conducted on the different parts of the plant, there is still no analytical method that enables the quantification of the compounds in the Moringa products in the market. The aim of this research was to develop an HPLC separation method that can be used to quantify the compounds found in the Moringa oleifera products. Compounds were extracted from the seeds of Moringa oleifera using the maceration method with a mixture of water and ethanol (1:1 v/v). The compounds were isolated using preparative HPLC. The structures of the compounds were elucidated using FTIR, NMR and MS. An HPLC separation method for quantification of the isolated compounds was developed and validated. The method was applied to the crude extract to quantify the isolated compounds in the extract. The following compounds 3-caffeoylquinic acid, 4-(α-L-Rhamnosyloxy) benzyl isothiocyanate, O-ethyl-[4-(α-L-Rhamnosyloxy) benzyl] thiocarbamate and O-butyl-[4-(α-L-Rhamnosyloxy) benzyl] thiocarbamate were isolated at percentage purities ranging from 90 to 99%. The HPLC separation method for quantification showed a linear relationship between peak area and concentration of the compounds with regression coefficients ranging from 0.9977 to 0.9994. The method is also precise with % RSD values between 0.01 and 1.16%. The method was shown to be specific to the compounds of interest. The percentage distribution of compounds in 50 mg of the seeds extract was between 0.25 and 1.10 % w/w. This study successfully developed and validated an HPLC separation method for four compounds found in the seeds of Moringa oleifera and quantified them in the crude extract of the seeds found in Zambia. This method can be used for identification and quantification of these four compounds in any of the Moringa products. As far as it could be ascertained this is the first time that such a method has been developed for these compounds / Chemistry / M. Sc. (Chemistry)

The investigations detailed in this dissertation have been conducted to address the paucity of pharmacokinetic information, in published literature, pertaining to cyclizine. The areas of investigation have included the selective quantitation of both cyclizine and its demethylated metabolite, norcyclizine in serum and urine, assessment of stability of both compounds in stored biological samples, dosage form analysis, dissolution rate testing of tablets, and bioavailability and pharmacokinetics following administration of an intravenous solution, and tablets to humans. High-performance liquid chromatography (HPLC) was used as the main analytical technique throughout these studies. An original HPLC method employing ultraviolet detection with a limit of quantitation of 5μg/ℓ was developed for the determination of cyclizine in serum and both cyclizine and norcyclizine in urine, Solid-phase extraction using extraction columns packed with reversed-phase C18 material, and followed by a simple phase-separation step proved successful for the accurate and precise isolation of the compounds. The validated method was applied to the analysis of serum and urine samples from a pilot study in which a single volunteer was administered 50mg of cyclizine hydrochloride. Several samples collected during the pilot study revealed the presence of both drug and metabolite in concentrations below the limit of detection. In order to improve the selectivity and sensitivity of the analytical method an HPLC method with electrochemical detection operating in the "oxidative-screen" mode was developed. The solid-phase extraction procedure was modified slightly and the method found to be precise, accurate, selective and highly sensitive with a limit of quantitation of Iμg/g/l for both cyclizine and norcyclizine in both serum and urine. This method was applied to the determination of both compounds after intravenous and oral administration of cyclizine to humans. HPLC with electrochemical detection was used for the analysis of samples collected during dissolution studies on the batch of tablets used for pharmacokinetic studies. In addition, this method was used to assess content uniformity of the tablets and of samples from the batch of intravenous ampoules of cyclizine lactate. Dissolution studies showed that all tablets tested passed the compendial specifications for cyclizine. Content uniformity assessment revealed that within-batch uniformity existed for both the tablets and ampoules and, therefore, variations in pharmacokinetic parameters for the drug would more than likely be as a result of inter- and intra-individual variability within the subject population. Pharmacokinetic information for cyclizine was obtained following administration of an intravenous bolus dose of cyclizine lactate as a solution, oral administration of cyclizine hydrochloride as a single dose of 50mg and as fixed multiple doses of 50mg every 8 hours for five days. Further information was acquired following administration of single doses of 100mg and 150mg cyclizine hydrochloride. Data collected from these studies were evaluated using both compartmental and non-compartmental techniques. Cyclizine was rapidly absorbed following oral administration with mean kₐ = 1.54 hr⁻¹ and was found to have an absolute bioavailability (F) of 0.47. The presence of norcyclizine in serum following oral and not intravenous dosing suggests cyclizine is susceptible to "first-pass" metabolism in either the gut wall or the I iver. Mean ClTOT determined following the intravenous dose was 0.865 ℓ/hr/kg. The mean ClTOT of 0.823 ℓ/hr/kg calculated following oral dosing, using a unique value of F for each subject compared favourahly with that obtained following intravenous dosing. Renal clearance of cyclizine is negligihle indicating that non-renal routes of elimination account for the majority of removal of cyclizine form the body. Cyclizine is extensively distributed and the mean Vz following an intravenous dose was 16.70 ℓ/kg. This value is lower than that calculated from all oral studies from which the mean Vz was determined to be 25.74 ℓ/kg. Cyclizine is eliminated slowly with a mean elimination t½ = 20.11 hours. Cyclizine dose not appear to follow dosedependent kinetics and therefore, inability to predict steady state levels are more than likely due to accumulation as a result of frequent dosing rather than saturation of elimination mechanisms. Modelling of intravenous data to one-compartment (lBCM), two-compartment (2BCM) and threecompartment models indicated that the pharmacokinetics of cyclizine can be adequately described by a 3BCM. The drug is rapidly distributed into a "shallow" peripheral compartment (α = 9.44 hr⁻¹ , and k₂₁ = 2.09 hr⁻¹ ), and slowly distributed to the "deep" peripheral compartment (β = 0.451 hr⁻¹ and k₃₁ = 0.120 hr⁻¹ ). Modelling of all oral data indicated that a 2BCM best described the pharmacokinetics of the drug, however, distribution to the peripheral compartment is not as rapid as to the "shallow" peripheral compartment following the intravenous dose. Mean distribution parameters were α = 0.64 hr⁻¹1 and, k₂₁ = 0.39 hr⁻¹. Mean CITOT following intravenous dosing of 0.70 ℓ/hr/kg was similar to the mean CIToT of 0.73 ℓ/hr/kg determined after oral dosing. The mean distribution volume at steady state determined following intravenous dosing (17.78 ℓ/kg) was lower than that obtained from the oral studies (25.52 ℓ/kg). The mean terminal elimination half-lives calculated for cyclizine following fitting of intravenous and oral data was 25.09 hours. In general, mean pharmacokinetic parameters calculated following titting of data to a 2BCM after oral administration correlate closely with those calculated using non-compartmental techniques. However, the pharmacokinetics following intravenous dosing are better described by a 3BCM and a close correlation between parameters estimated using noncompartmental techniques and compartmental techniques is evident when a 3BCM model is used.

Made available in DSpace on 2014-12-02T11:16:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-07-10Bitstream added on 2014-12-02T11:21:41Z : No. of bitstreams: 1 000800265.pdf: 1317086 bytes, checksum: 617587c5dc929a7726bd7a48f2571ce3 (MD5) / O sistema de produção com ou sem a pres ença de palhada, bem como, a aplicação de vinhaça nos canaviais, podem levar a alterações nas propriedades do solo e influenciar a disponibilidade dos herbicidas na solução do solo. Diante disto, o presente trabalho teve por objetivo avaliar a influência d a água, água após passar pela palha de cana - de - açúcar e vinhaça na disponibilidade na solução do solo dos herbicidas amicarbazone, clomazone, diuron, hexazinone, imazapic, sulfentrazone e tebuthiuron em diferentes solos. Adotou - se o esquema fatorial 3 x 31, com delineamento em blocos inteiramente casualizados com três repetições, sendo utilizadas 31 amostras de solos distintos quanto às características físicas e químicas e três tratamentos (água, água de lavagem de palha e vinhaça). As amostras de solo foram dispostas em bandejas e submetidas à aplicação dos herbicidas, em seguida foram acondicionadas em cartuchos plásticos e saturadas com água deionizada, água de lavagem de palha e vinhaça, permanecendo em repouso durante 18 horas sob refrigeração (8 ± 3 ° C) . Posteriormente, fez - se duas extrações, na primeira quantificou - se os herbicidas presentes na solução do solo e na segunda foi realizada a extração total do herbicida remanescente no solo para determinação da porcentagem de recuperação de cada herbicida t estado. Para as quantificações utilizou - se um sistema LC - MS/MS, composto por um Cromatógrafo Líquido de Alta Performance (HPLC) acoplado ao espectrômetro de massas. O amicarbazone e o imazapic foram mais 2 disponibilizados na solução dos solos com a aplicaçã o de água e água de lavagem de palha na maioria das amostras. Todavia, a adição de vinhaça promoveu uma maior disponibilização do diuron e tebuthiuron em todos os solos. O clomazone, hexazinone e sulfentrazone não apresentaram diferença significativa entre os ... / The pr oduction system with or without the straw as how the sugarcane vinasse application may cause some changes in the soil properties and may influence the avaiability of the herbicides in the soil solution. Based on that, the objective of this study was to eva luate the water influence after passing throught the sugarcane straw and the vinasse, both correlated with the availability of the herbicides a micarbazone, clomazone, diuron, hexazinone, imazapc, sufentrazone and tebuthiuron in the soil solution in differ ent kinds of soils. The factorial 3 x 31 with complete randomized block design, with three replications, was used with 31 physical and chemical different soil samples and three treatments (water, wash water straw and vinasse). The soil samples were arrange d on trays and submitted to the herbicides application, then they were placed in plastic cartridges and satured with deionized water, wash water straw and vinasse, and remained resting for 18 hours under refrigeration (8 ± 3 o C) . After that, two extrations were made: the first one quantifying the presence of the herbicides in the soil solution and in the second one the total extraction of herbicide remaining in the soil was taken to determine the recovery percentage of each herbicide tested. For quantificat ions it was used a LC - MS/MS system, compound of a High Performance Liquid Chromatograph (HPLC) coupled with mass spectrometer. The amicarbazone and imazapic herbicides, in most samples, were more available in the soil solution with the water application an d in the wash water straw. However, vinasse had promoted an increase availability of diuron and tebuthiuron in all soils. Clomazone, hexazinone and sulfentrazone showed no significative difference between the treatments. The herbicides with the highest fre quency of availability of herbicides in soils were imazapic, hexazinone, amicarbazone and tebuthiuron. However, about 6% of ...