Distribution of etanidzole into human brain tumors: Implications for treating high grade gliomas

Selwyn J. Hurwitz, C. Norman Coleman, Nancy Riese, Jay S. Loeffler, Eben Alexander, Lori Buswell, Tamlyn Yee Neben, Leon Sahargel, Robert A. Kramer

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Etanidazole was developed as an oxygen-mimetic radiosensitizer less lipophilic than misonidazole. Sensitization depends on an adequate concentration of drug in the tumor at the time of irradiation. Therefore, due to the presence of the blood-brain barrier, brain tumors may theoretically be difficult to radiosensitize due to the hydrophilic characteristics of etanidazole. Based on previous reports of loss of BBB integrity in brain tumors, we investigated the ability of etanidazole to penetrate into malignant gliomas of patients receiving etanidazole as part of a Phase I continuous infusion protocol. The patients had completed previous external beam irradiation. Twenty-two patients were studied and their etanidazole plasma and biopsy data were compared to the 2-compartment model derived from a second group of 19 patients with bolus etanidazole. Etanidazole concentration in brain tumor biopsies varied widely and appeared to be clustered into a higher and a lower pharmacokinetic group having mean tumor to well-perfused second compartment ratios of 1 and 0.25, respectively. Both high and low etanidazole concentrations were evident in different biopsies obtained from the same patient. Correlations between histology and tissue concentrations suggested that the higher level correspond to malignant tissue. These data indicate that the blood brain barrier is disrupted to varying degrees by the brain tumor and/or prior irradiation and that etanidazole penetrates into brain tumors.

Original languageEnglish (US)
Pages (from-to)573-576
Number of pages4
JournalInternational journal of radiation oncology, biology, physics
Issue number3
StatePublished - 1992
Externally publishedYes


  • 2-nitroimidazoles
  • Brachytherany
  • Brain tumors
  • Chemical modifiers
  • Continuous infusion
  • Etanidazole
  • Hypoxic cell sensitizers
  • Radiosensitizers
  • SR 2508

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research


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