Molecule

Description

Neurological Disease

Description

Safinamide Mesylate is mesylate salt of Safinamide, which selectively and reversibly inhibits MAO-B with IC50 of 0.45 μM.

Targets

IC₅₀

In Vitro

Safinamide is a highly selective MAO-B inhibitor in rat brain mitochondria, with an IC50 of 98 nM. safinamide inhibits MAO-B in human brain with an IC50 of 9 nM. Safinamide has high affinity for the Na⁺ channel-binding site II in rat cortical membranes, with an IC50 of 8 μM. Safinamide inhibits the fast Na⁺ currents in a concentration- and state-dependent manner in rat cortical neurons. Safinamide blocks N-Type Ca²⁺ currents in rat cortical neurons with IC50 23 μM. Safinamide inhibits glutamate release induced by depolarizing conditions in rat hippocampal synaptosomes with IC50 of 9 μM. Safinamide incubated 1 hour before veratridine reduces the neuron damage with an IC50 1.4 μM through blockade of opening voltage-dependent Na⁺ and Ca²⁺ channels in rat primary cortical neurons. ^[1] Safinamide binds to human MAO B with a Ki of 0.5 μM. Safinamide binds to human MAO B in an extended conformation occupying both flavin and entrance cavity. ^[2]

In Vivo

Safinamide orally administrated dose-dependently inhibits mouse brain MAO-B with IC50 of 0.6 mg/kg, and MAO-B activity recovers quickly, starting from 8 hours. Safinamide significantly inhibits cell body degeneration in the substantia nigra pars compacta. Safinamide intraperitoneally administered 15 minutes before kainic acid protects against hippocampal neuron loss, starting at 10 mg/kg showing neuroprotective properties. Safinamide intraperitoneally administrated at dose of 100 mg/kg shows a relevant neurorescuing effect on hippocampal neurons when given 3 hours after ischemia. Safinamide has a high oral bioavailability (80–92%), is rapidly absorbed in plasma after reaching the peak within 0.5–2 hours declines, with a terminal half-life of about 3, 7, and 13 hours in mice, rats, and monkeys, respectively. ^[1]

Clinical Trials

Safinamide is currently in a Phase II clinical trial in Parkinson's Disease.

Features

5000-fold more potent in inhibiting MAO-B versus MAO-A

Description

Safinamide intraperitoneally administrated at dose of 20 mg/kg significantly increases DA levels (60%) when coadministered with levodopa (100 mg/kg IP) and benserazide (12.5 mg/kg IP) in DA-depleted C57BL mice 15 days after MPTP treatment. ^[1]

Enzyme Activity Assay

The enzyme activities are assessed with a radioenzymatic assay using the selective substrates 14C-phenylethylamine (PEA) for MAO-B. The mitochondrial pellet (500 μg protein) is resuspended in 200 μL of 0.1 M phosphate buffer, pH 7.40, and is added to 50 μL of the solution of safinamide or of buffer and incubated for 30 min at 37 °C (preincubation). Then the substrate in 50 μL of 0.5 μM ¹⁴CPEA is added and the assay mixture is incubated at 37 °C for 10 min. The reaction is stopped by adding 0.2 mL of perchloric acid. After centrifugation, the acidic radioactive metabolites are extracted with 3 mL of toluene and the radioactivity of the organic phase is measured by liquid scintillation spectrometry at 90% efficiency. The enzymatic activity is expressed as nanomoles of substrate transformed per milligram of protein per minute (nmol mg^-1 min^-1). Safinamide inhibition curves are obtained from five to eight different concentrations (10^-10-10^-5 M), each in duplicate, and the IC50 is determined using nonlinear regression analysis.

Animal Models

DA-depleted C57BL mice

Formulation

sterile 0.9% sodium chloride solution

Doses

20 mg/kg

Administration

Inject intraperitoneally in a single dose