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Browsing by Subject "johdoksenmuodostus"

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  • Mattila, Susanna (2012)
    The aim of the stydy was to evaluate how different chemical derivatization methods are suitable for characterization of regional isomers of different glucuronide conjugates. Glucuronidation is one of the phase II metabolic reactions where more water soluble and often inactive substances are produced. Different functional groups may be subjected to glucuronidation. It is important to determine the exact position of glucuronidation, as the isomers may possess different toxicological or pharmacological properties. For example morphine-6-glucuronide is pharmacologically more active than morphine itself. The glucuronide conjugates are commonly detected by liquid chromatography tandem mass spectrometry (LC-MS/MS) and/or nuclear magnetic resonance (NMR). MS/MSspectra of native molecule and glucuronidated molecule are usually similar because of an initial loss of 176 Da, i.e. monodehydrated glucuronic acid. This fact often makes it impossible to determine the site of glucuronidation. Samples of NMR-analysis requires larger amounts of sample materials than MS-analysis. Many of those derivatization reagents tested in this study were not reacting as they were supposed to react according to literature. O-phthalaldehyde (OPA) and 9-fluorenylmethyl chloroformate (FMOC) were forming derivatives as expected and those reagents are very suitable for glucuronide conjugates studies. At the end of the studies the site of the glucuronidation of dopamine- and serotonineglucuronides were evaluated by derivatization with OPA and FMOC. Derivatization with OPA and FMOC successfully gave information about the region of the glucuronide acid in dopamine- and serotoninemolecules. The assumptions supposed to be correct according to NMR-studies presented in literature.