Abstracts Category : Other

Practical applications of infrared, Raman and nuclear magnetic resonance spectroscopic techniques for qualitative, quantitative and structural analysis of pharmaceutical drugs, cementitious material and organic molecules containing phosphorous

by Sudhaunshu Shrikant Purohit

The study of the interaction between matter and electromagnetic radiation which procreated the wide branch named as Spectroscopy has gained tremendous attention since the last century. Atoms and molecules respond to electromagnetic radiation to produce their unique spectra which can be used to detect, identify and quantify valuable information about the substance under study. Since, its conception, spectroscopy has been widely used in physical and analytical chemistry and has ramified various techniques depending on the different types of radiation. This dissertation focuses on implementation of various spectroscopic techniques such as Infrared, Raman and Nuclear Magnetic Resonance (NMR) spectroscopy in order to determine theoretical, conformational, qualitative and quantitative properties of different molecules under study. Understanding the physical structure of a molecule is fundamental for function, dynamic, and mechanism studies. Infrared and Raman spectroscopy are two of the most widely used and powerful techniques for the accurate determination of molecular symmetry and conformational stability. They provide information of molecular vibrations and the two techniques complement each other to yield more complete information about the molecular structure than when they are evaluated separately. One of the focus of this dissertation is the determination of the structural parameters, conformational stability, vibrational assignments and <i>ab initio</i> calculations of organic molecules containing five membered ring and phosphorous by utilizing infrared and Raman spectral techniques. The findings of my spectroscopic, structural, and theoretical studies are based on infrared and/or Raman spectra of gas, liquid, solid as well as variable temperature xenon solutions, and microwave spectrum which are supported by <i>ab initio</i> and DFT calculations. Nearly four decades ago the potential of Nuclear Magnetic Resonance (NMR) spectroscopy for the quantitative analysis of organic chemicals was first demonstrated. Along with solution state NMR, for past two decades solid state NMR spectroscopy has also come to the forefront of quantitative analytical techniques in pharmaceutical research, as, both of these techniques have been successfully applied to the study of polymorphism in pharmaceutical drugs at both the qualitative and quantitative levels. The investigation of our research presented in this dissertation was initiated by selecting AIDS, the predominant pandemic of twenty-first century and Tenofovir (TFV), a well-tested antiretroviral drug that has proven its mettle against HIV/AIDS. In order to be able to accurately quantify the amount of drug being delivered in human body is a crucial requirement of any drug development process. We specifically focused on phosphorous containing drugs and hence, a part of this dissertation describes about the development and implementation of a general 31 P qNMR method to achieve direct, real time quantification of <i> in vitro</i> drug release. We