99mTc-propylene amine oxime (99mTc-PnAO); a potential brain radiopharmaceutical

Abstract

Propylene amine oxime (PnAO) forms a neutral lipid soluble complex with 99mTc. 99mTc-PnAO can be prepared by simple reduction of 99mTc-pertechnetate with stannous ion in the presence of excess PnAO in saline at or near neutral pH. This agent will passively penetrate biological membranes including the intact blood-brain barrier (BBB) as evidenced by the high brain uptake observed shortly after IV injection. The first-pass extraction efficiency in baboons was estimated to be 80% at normal blood flow. This agent or a derivatized form of 99mTc-PnAO may be useful in assessment of regional cerebral blood flow (rCBF) in humans.

Linearization Correction of 99mTc-Labeled Hexamethyl-Propylene Amine Oxime (HM-PAO) Image in Terms of Regional CBF Distribution: Comparison to C15O2 Inhalation Steady-State Method Measured by Positron Emission Tomography

“…Correspondingly, the higher the a, the lower the image contrast. from the early reports (Volkert et al , 1984;Ell et al , 1985;Holmes et al , 1985;Andersen et al , 1985;Lindegaard et al , 1986;Sharp et al , 1986;Leonard et al , 1986). This study was undertaken to validate the HM-PAO method in humans by directly com paring it to the C I5 0 2 -PET technique, which is at present one of the most reliable techniques for CBF tomography.…”

Preparation, characterization and biological evaluation of99mTc(CO)3-labelled cyclic polyamines

“…For 'standard' preparation of the technetium tricarbonyl complexes with cyclic polyamines, 0.1 ml of technetium tricarbonyl precursor prepared from an IsoLink 1 kit was added to 0.5 ml of a solution of the cyclic polyamine (1 mg/ml) adjusted to pH 11 by addition of 0.5 ml of a 0.5 M phosphate buffer pH 11 and the mixture was heated in a waterbath at 1008C for 15 min. When the influence of pH or temperature of the reaction mixtures on the labelling of cyclam was studied, 0.5 ml of a 0.5 M phosphate buffer of different pH (7,9,11) was added and labelling was performed at different temperatures (room temperature, 50, 70, 1008C). …”

“…[1][2][3][4][5] A positively charged 99m Tc(V)dioxo cyclam complex has been described [6] and characterized [7,8] more than 20 years ago. In this complex a central Tc(V) dioxo core is bound to the cyclam ligand via the four amine nitrogen atoms without deprotonation, resulting in a monocationic complex.…”

Single-photon emission computed tomography in neurotherapeutics

“…Investigators at Amersham 25 and Volkert et al 26 at the University of Missouri developed the first of the technetium agents approved by the FDA for use in humans, 99m Tc HMPAO (Ceretec).…”