Bioanalysis of Pteroyl Derivatives in Various Aspects of Human Health

Abstract

This dissertation describes the development of bioanalytical strategies for a group of experimental and known therapeutic agents and chemically related essential substances. The array of analytes include the antifolate methotrexate, its various (in)active metabolites and related bio-conjugates, plus several forms of folic acid family, a group of essential substances not synthesized by mammalian species, but endogenously required in numerous biochemical processes. These analytes all share a common structural feature, the heterocyclic pteridine ring system. Analyte identity results from variations of the ptereridine-ring system redox state, a result of minor structural variations of the heterocyclic ring and changes in conjugation status (i.e. polyglutamated or nanoparticle conjugated). Specific and sensitive detection of the individual species was of high interest, as the various chemical forms of these substances may constitute biomarkers for individualizing low dose MTX therapy in autoimmune diseases such as JIA, but is also required for the (pre)clinical studies of novel nano-device MTX drug delivery systems. The dissertation presents state-of-the-art bioanalytical methodology suitable for the specific determination of any specific analyte in the presence of all other analytes. The strategy for each particular analyte possesses its own unique strength and weakness, with the final strategy collectively being based on the specific structure and associated physical-chemical property of a given analyte, the biological environment, and the clinical question to be answered.