Ifenprodil (+)-tartrate salt (hemitartrate salt)

Ifenprodil is an atypical, selective, noncompetitive, voltage-independent partial antagonist of N-methyl-D-aspartate (NMDA) receptors. Its maximal inhibition is approximately at 90%. Ifenprodil inhibits GluN2B-containing receptors with high affinity and is more potent for GluN1/GluN2B receptors. Ifenprodil action is pH-dependent and may cause an increase in tonic proton inhibition. There is evidence that ifenprodil binds outside the ion channel pore to the large interlobe cleft of the NR2B N-terminal domain and acts at a discrete sites with an allosteric interaction. Mutations at distinct residues in the R domain of NR1 and NR2B greatly influence ifenprodil inhibition, thus it seems that this region may form part of the ifenprodil binding site^1-3. IC₅₀ values of ifenprodil are 0.15 μM for NR2B subunit, 39 μM for NR2A, 29 μM for NR2C and 76 μM for NR2D².

NMDA receptors are gated ion channels by glutamate and are involved in numerous physiological and pathological processes including synaptic plasticity, chronic pain and psychosis⁴.

Ifenprodil has neuroprotective abilities in in vivo models of cerebral ischemia and has the ability to protect cultured neurons from NMDA mediated toxicity without many of the side effects caused by NMDA antagonist³.

Ifenprodil was proven to be a useful pharmacological tool to study the structure and function of NMDA receptors. Ifenprodil rise pharmaceutical interest because of its therapeutic potential for neurological and psychiatric disorders such as treating pain⁴.