WEAKLY BASIC 2-NITROIMIDAZOLES FOR THE NON-INVASIVE DETECTION OF TISSUE HYPOXIA

摘要

The present invention incorporates weakly basic substituents (pKa about 8 or greater) such as pyrrolidine, piperidine, piperazine and azapane moieties in halogenated 2-nitromidazoles as a major improvement over prior art for the non-invasive detection of cellular hypoxia in normal and malignant tissues. The invention features the use of [18F] positron emission tomography, [19F] magnetic resonance spectroscopy, and [19F] magnetic resonance imaging. Improvements over prior art compounds are six-fold. 1) Salts of weakly basic reagents are highly water-soluble which facilitates administration. 2) Unreacted reagents are rapidly cleared from systemic circulation thereby decreasing background noise. 3) Reagents with weakly basic substituents are concentrated in tissue ~ 3 fold above plasma levels thereby increasing binding intensity and enhancing signal detection. 4) Conjugate bases of weakly basic reagents have intermediate octanol-water partition coefficients that facilitate their penetration into all tissues including brain. 5) Cellular adducts of reagents containing weakly basic substituents are more stable than reagents of prior art. 6) Reagents with weakly basic substituents are effective for the detection of transient hypoxia in solid tissue.