RESUMO
Neurounina-1 [chemical name: 7-nitro-5-phenyl-1-(pyrrolidin-1-ylmethyl)-1H-benzo[e][1,4]diazepin-2(3H)-one] is a new compound provided with relevant neuroprotective effect during stroke and in neonatal hypoxia by increasing the Na+/Ca2+ exchanger (NCX) isoforms NCX1 and NCX2 activity. This study shows for the first time, the development and validation of a sensitive and selective method for analysis of neurounina-1 in beagle dog plasma by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The sample preparation consisted of extraction of the analyte and the internal standard (IS) (ropivacaine) from plasma (50 µL) by liquid-liquid extraction using acetonitrile (100 µL). The selected reaction monitoring mode of the positive ion was performed and the precursor to the product ion transitions of m/z 365 > 83 and m/z 275 > 126 were used to measure the derivative of neurounina-1 and ropivacaine. The chromatographic separation was achieved using a Phenomenex C18 Luna (150 mm × 4.6 mm × 5 µm) analytical column with an isocratic mobile phase composed of methanol/acetonitrile/water (50/40/10, v/v/v) + 0.1% formic acid + 1 M ammonium formate. The method was linear over a concentration range of 1-500 ng/mL. The method was applied to evaluate the pharmacokinetics of neurounina-1 after a single intravenous administration of three different doses (0.1 mg/kg, 0.3 mg/kg, and 1 mg/kg) to beagle dogs (n = 5). The mean AUC0-tlast values were 26.10, 115.81, and 257.28 ng∗h/mL following intravenous administration of 0.1, 0.3, and 1 mg/kg, respectively. Linear pharmacokinetics was observed up to 1.0 mg/kg. The neurounina-1 was rapidly eliminated, with mean CL values of 46.24, 47.57, and 69.15 L/h, Vd of 130.31, 154.15, and 210.79 L and t1/2 of 2.14, 2.54, and 2.04 h after intravenous administration of 0.1, 0.3, and 1 mg/kg, respectively. This new analytical method allows the rapid determination of the neurounina-1, a new developed compound, able to exert a remarkable neuroprotective effect in the low nanomolar range.
RESUMO
BACKGROUND: Riluzole is a benzothiazole anticonvulsant used in the treatment of patients with amyotrophic lateral sclerosis and it is being investigated for clinical use in patients with spinal cord injury. The present study evaluated the pharmacokinetics of riluzole in beagle dogs after oral dose administration. METHODS: The oral doses (1.5, 5, 15 and 50 mg/kg) of riluzole were administered to beagle dogs and blood samples were collected from 0 h to 24 h post drug administration. Riluzole was quantified by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). RESULTS: The method was sensitive, precise, accurate and selective to riluzole quantification in plasma of beagle dogs. The pharmacokinetics following oral administration was linear from 1.5 to 15 mg/kg and the t1/2 was 2.16, 1.5, 1.8 and 3.0 h after oral administration of 1.5, 5.0, 15 and 50 mg/kg riluzole. CONCLUSION: The riluzole pharmacokinetics was linear up to 15 mg/kg and had a significantlyshorter t1/2 in beagle dogs than in humans.