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Mass spectrometric study to characterize thioisoindole derivatives of aminoglycoside antibiotics

Authors

  • Eliangiringa Kaale,

    1. Department of Medicinal Chemistry, School of Pharmacy, P.O. Box 65545, Dar Es Salaam, Tanzania
    2. Laboratory for Pharmaceutical Chemistry and Drug Analysis, Faculty of Pharmacy, K.U.Leuven, E. Van Evenstraat 4, 3000 Leuven, Belgium
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  • Cindy Govaerts,

    1. Laboratory for Pharmaceutical Chemistry and Drug Analysis, Faculty of Pharmacy, K.U.Leuven, E. Van Evenstraat 4, 3000 Leuven, Belgium
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  • Jos Hoogmartens,

    1. Laboratory for Pharmaceutical Chemistry and Drug Analysis, Faculty of Pharmacy, K.U.Leuven, E. Van Evenstraat 4, 3000 Leuven, Belgium
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  • Ann Van Schepdael

    Corresponding author
    1. Laboratory for Pharmaceutical Chemistry and Drug Analysis, Faculty of Pharmacy, K.U.Leuven, E. Van Evenstraat 4, 3000 Leuven, Belgium
    • Laboratory for Pharmaceutical Chemistry and Drug Analysis, Faculty of Pharmacy, K.U.Leuven, E. Van Evenstraat 4, 3000 Leuven, Belgium.
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Abstract

Aminoglycoside antibiotics are widely used to treat serious Gram-negative and Gram-positive bacterial infections. The lack of a UV chromophore presents a problem in the analysis of aminoglycosides. Derivatization with 1,2-phthalic dicarboxaldehyde (OPA) in the presence of a thiol made it possible to introduce a UV chromophoric thioisoindole moiety. A qualitative mass spectrometry study was carried out to confirm the molecular identity of the products formed. The conditions described earlier to derivatize gentamicin and kanamycin yielded products in which all primary amino groups are fully derivatized. On the other hand, with tobramycin and amikacin, there was also formation of incompletely derivatized products that contained one thioisoindole group less than the fully derivatized product. This study has therefore brought an additional insight into the nature of the OPA-aminoglycoside derivatives studied. Copyright © 2005 John Wiley & Sons, Ltd.

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