Polynitroxyl hemoglobin: A pharmacokinetic study of covalently bound nitroxides to hemoglobin platforms

Paul W. Buehler, Chad R. Haney, Anil Gulati*, Li Ma, Carleton J C Hsia

*Corresponding author for this work

Research output: Contribution to journalArticle

25 Scopus citations


Adding antioxidant activities to hemoglobin-based oxygen carriers (HBOCs) represents a means of reducing cell-free hemoglobin-mediated oxidative cascades. We have covalently bound nitroxides, a class of antioxidant enzyme mimetics, to HBOCs. The objectives of this study were (1) to evaluate the pharmacokinetic (PK) effects of administering nitroxide covalently bound to HBOCs compared to those of free nitroxide coadministered with HBOCs and (2) to elucidate the effects of differing molecular weight HBOCs on the PK of bound nitroxide in a conscious guinea pig model of 25% blood exchange transfusion. Two HBOC platforms were used, intramolecular cross-linked hemoglobin (XLHb) and dextran polymerized/conjugated XLHb (PolyHb). Polynitroxylation was achieved by reacting 4-(2-bromoacetamido)-2,2,6,6,-tetramethylpiperidine-1-oxyl with XLHb or PolyHb to form polynitroxylated XLHb and polynitroxylated PolyHb, respectively, whereas a physical mixture of XLHb or PolyHb with 4-hydroxy-2,2,6,6- tetramethylpiperidine-1-oxyl was prepared to reflect a molar equivalence to HBOC-bound nitroxide. Plasma concentrations of two redox states, nitroxide and hydroxylamine, were determined by electron paramagnetic resonance spectroscopy. Results are presented to illustrate the influence of covalent labeling and HBOC molecular weight on nitroxide PK. The therapeutic potential of polynitroxylation of HBOCs as it relates to observations from the current and previously reported studies is discussed.

Original languageEnglish (US)
Pages (from-to)124-135
Number of pages12
JournalFree Radical Biology and Medicine
Issue number1
StatePublished - Jul 1 2004



  • AUC
  • C
  • C
  • Free radicals
  • Last measured plasma concentration
  • Maximum plasma concentration
  • Nitroxide
  • Nitroxide bioreduction
  • Noncompartmental pharmacokinetics
  • PNH
  • PolyPNH
  • Polynitroxyl hemoglobin

ASJC Scopus subject areas

  • Biochemistry
  • Physiology (medical)

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