Ibogaine labeling with 99mTc-tricarbonyl: synthesis and transport at the mouse blood-brain barrier.
Journal of pharmaceutical sciences December 1, 2009 Nicolas Tournier, Pascal André, Sandy Blondeel et al. 14 citations
Radiolabeling the neuroactive compound ibogaine with technetium-99m tricarbonyl produced a tracer that entered the mouse brain poorly, at a rate similar to other tracers known to have low brain uptake. The brain entry rate was about 70 times lower than that of a standard clinical brain-imaging agent. Neither the labeled ibogaine nor the tricarbonyl core alone were substrates for the main efflux transporters at the blood-brain barrier. Instead, the limited brain penetration was attributed to the compound's lipophilicity and its interaction with the membrane's positive dipole potential, as lowering that potential with phloretin increased transport roughly threefold. The findings indicate that ibogaine directly labeled with this radionuclide is unsuitable for central nervous system imaging.