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Creators/Authors contains: "Olupathage, Harshana"

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  1. The characterization of drug-target interactions is a key component of drug discovery, testing, and development. Affinity chromatography is one approach that can be used for this type of analysis. For instance, this may be done by using an immobilized target as a stationary phase and a drug as the applied solute. This review will discuss the various ways in which affinity chromatographic methods have been used to examine drug-target interactions, with an emphasis on high-performance methods. The general principles of this approach and factors to consider in its use for drug-target interaction analysis will first be examined. Methods based on zonal elution or frontal analysis for binding and competition studies will then be discussed. Various techniques for kinetic studies will next be considered, along with approaches that employ secondary binding agents and hybrid techniques. In each case, the general principles and theory of an approach will be given along with examples of its use in drug-target interaction studies. Advantages or limitations of each approach will be provided as well. This information should make it possible in the future to extend these techniques to other drug-target systems of interest in biomedical research and drug testing or development. 
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  2. The analysis of interactions between biological agents or with surrounding chemicals is important in many areas of modern biochemical, biomedical, and environmental research. Microscale platforms based on affinity chromatography have been shown to be a powerful set of tools for these studies. This approach makes use of an immobilized binding agent as a stationary phase in a microscale platform for either direct examination of the interactions of this agent with an applied target solute or as a secondary capture agent to probe a solution‐phase interaction. This review will examine the various platforms and strategies that have been used in microscale affinity chromatography, or µAC, to characterize and study biointeractions. The general principles of µAC and schemes based on this approach will be examined, along with applications of this technique. Examples of approaches that will be considered will include zonal and frontal analysis methods, as well as a variety of schemes by which µAC can be employed in kinetic studies. In each case, the theory and principles of these methods will be provided along with examples of their use in biointeraction studies. 
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  3. Chromatography is a robust and reliable separation method that can use various stationary phases to separate complex mixtures commonly seen in metabolomics. This review examines the types of chromatography and stationary phases that have been used in targeted or untargeted metabolomics with methods such as mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. General considerations for sample pretreatment and separations in metabolomics are considered, along with the various supports and separation formats for chromatography that have been used in such work. The types of liquid chromatography (LC) that have been most extensively used in metabolomics will be examined, such as reversed-phase liquid chromatography and hydrophilic liquid interaction chromatography. In addition, other forms of LC that have been used in more limited applications for metabolomics (e.g., ion-exchange, size-exclusion, and affinity methods) will be discussed to illustrate how these techniques may be utilized for new and future research in this field. Multidimensional LC methods are also discussed, as well as the use of gas chromatography and supercritical fluid chromatography in metabolomics. In addition, the roles of chromatography in NMR- vs. MS-based metabolomics are considered. Applications are given within the field of metabolomics for each type of chromatography, along with potential advantages or limitations of these separation methods. 
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  4. Immunoaffinity chromatography (IAC) is a type of liquid chromatography that uses immobilized antibodies or related binding agents as selective stationary phases for sample separation or analysis. The strong binding and high selectivity of antibodies have made IAC a popular tool for the purification and analysis of many chemicals and biochemicals, including proteins. The basic principles of IAC are described as related to the use of this method for protein purification and analysis. The main factors to consider in this technique are also presented under a discussion of the general strategy to follow during the development of a new IAC method. Protocols, as illustrated using human serum albumin (HSA) as a model protein, are provided for the use of IAC in several formats. This includes both the use of IAC with traditional low‐performance supports such as agarose for off‐line immunoextraction and supports used in high‐performance IAC for on‐line immunoextraction. The use of IAC for protein analysis as a flow‐based or chromatographic immunoassay is also discussed and described using HSA and a competitive binding assay format as an example. 
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