Implementation of Solution and Solid Sate Nuclear Magnetic Resonance (NMR) Spectroscopic Techniques for Quantitative and Qualitative Analysis of Molecular Species

Abstract

In this dissertation, spectroscopy has been used to solve a variety of problems in different domains of science. Therefore, each chapter consists of different examples that have been addressed using different concepts of spectroscopy. The objective of part I (application of solution state NMR spectroscopy in pharmaceutical sciences) is to apply NMR techniques in different pharmaceutical projects. In chapter3, a real-time quantification of in vitro Bortezomib (BTZ) release from alginate microparticles using a solution state quantitative boron nuclear magnetic resonance (11B qNMR) method is presented. The method was validated according to International Conference on Harmonization (ICH) guidelines. Therefore, several analytical performance parameters were discussed such as limit of detection (LOD), limit of quantification (LOQ), linearity, specificity, accuracy, precision and robustness. The 11B qNMR method was applied to the in vitro release study of a model drug, bortezomib (BTZ) from alginate microparticles and results were compared to a commonly used dialysis method. Throughout the release study, the dialysis method consistently underestimated the level of drug released, probably due to the separating membrane that can interfere with the real-time drug transport process. Overall, compared to the dialysis method, the direct 11B qNMR method was accurate and provided a direct and real-time quantification of BTZ for an effective study of drug release kinetics. Similarly, in chapter 4, a 19F qNMR method was developed and validated and then applied to study the real-time release of maraviroc from a microparticle formulation in a vaginal and seminal stimulated environment. Different possibilities were discussed to control the release profile such as the crosslinking process and a pH sensitive polymer. In chapter 5, the project is a collaborative effort between the department of Chemistry and School of Pharmacy. Our contributions in that project are to utilize 11B NMR spectroscopy technique as a characterization tool for the reaction progression. Moreover, to perform theoretical and experimental calculations and compare them to each other in order to trace the reaction mechanism. The overall motivation of the project is to test an assumption about phenylboronic acid (PBA) to prevent HIV transmission. It has been found that phenylboronic acid can form boronic acid in the presence of cis-diol, like the one found in HIV-gp120 glycoproteins. In order to exam the proposed hypothesis, a derivative of phenylboronic acid was synthesized. The synthetic scheme and the spectroscopic results are presented and discussed in detail. The objective of part II (applications of solid-state NMR spectroscopy) is to apply SSNMR spectroscopy experiments in two projects to gain significant information about specific materials. In chapter 6, some main concepts of SSNMR spectroscopy are discussed as well as some basic SSNMR experiments. In chapter 7, boron carbide thin films were grown using plasma enhanced chemical vapor deposition (PECVD) under different growth conditions. Different possible spectroscopic techniques were discussed in order to discover the local physical structure of boron carbide thin films. However, most of these techniques have shown a lack of an ability to demonstrate the internal structure of thin films. SSNMR spectroscopy was successfully employed to reveal information about the internal structure of boron carbide thin films. In chapter 8, the optical properties of titanium oxide TiO2 were modified by introducing a hydrazine molecule. SSNMR spectroscopy was implemented to monitor the reaction progression of TiO2 to improve its optical properties.