Zonisamide-13C2,15N is intended for use as an internal standard for the quantification of zonisamide by GC- or LC-MS. Zonisamide is an antiepileptic agent.1 It selectively inhibits the repeated firing of sodium channels (IC50 = 2 μg/ml) in mouse embryo spinal cord neurons and inhibits spontaneous channel firing when used at concentrations greater than 10 μg/ml.2 In rat cerebral cortex neurons, zonisamide (1-1,000 μM) inhibits T-type calcium channels with a maximum reduction of 60% of the calcium current.3 Zonisamide inhibits H. pylori recombinant carbonic anhydrase (CA) and the human CA isoforms I, II, and V with Ki values of 218, 56, 35, and 21 nM, respectively.4,5 In mice, it has anticonvulsant activity against maximal electroshock seizure (MES) and pentylenetetrazole-induced maximal, but not minimal, seizures (ED50s = 19.6, 9.3, and >500 mg/kg, respectively). Zonisamide (40 mg/kg, p.o.) prevents MPTP-induced decreases in the levels of dopamine , but not homovanillic acid or dihydroxyphenyl acetic acid , and increases MPTP-induced decreases in the dopamine turnover rate in mouse striatum in a model of Parkinson's disease.6 Formulations containing zonisamide have been used in the treatment of partial seizures in adults with epilepsy. |1. Masuda, Y., Ishizaki, M., and Shimizu, M. Zonisamide: Pharmacology and clinical efficacy in epilepsy. CNS Drug Rev. 4(4), 341-360 (1998).|2. Rock, D.M., Macdonald, R.L., and Taylor, C.P. Blockade of sustained repetitive action potentials in cultured spinal cord neurons by zonisamide (AD 810, CI 912), a novel anticonvulsant. Epilepsy Res. 3(2), 138-143 (1989).|3. Suzuki, S., Kawakami, K., Nishimura, S., et al. Zonisamide blocks T-type calcium channel in cultured neurons of rat cerebral cortex. Epilepsy Res. 12(1), 21-27 (1992).|4. Nishimori, I., Vullo, D., Minakuchi, T., et al. Carbonic anhydrase inhibitors: Cloning and sulfonamide inhibition studies of a carboxyterminal truncated α-carbonic anhydrase from Helicobacter pylori. Bioorg. Med. Chem. Lett. 16(8), 2182-2188 (2006).|5. De Simone, G., Di Fiore, A., Menchise, V., et al. Carbonic anhydrase inhibitors. Zonisamide is an effective inhibitor of the cytosolic isozyme II and mitochondrial isozyme V: Solution and X-ray crystallographic studies. Bioorg. Med. Chem. Lett. 15(9), 2315-2320 (2005).|6. Yabe, H., Choudhury, M.E., Kubo, M., et al. Zonisamide increases dopamine turnover in the striatum of mice and common marmosets treated with MPTP. J. Pharmacol. Sci. 110(1), 64-68 (2009).

Flumequine-13C3is intended for use as an internal standard for the quantification of flumequine by GC- or LC-MS. Flumequine is a fluoroquinolone antibiotic.1It is active againstS. aureus, S. pyogenes, B. subtilis, E. coli, P. aeruginosa, S. faecalis, andK. pneumoniae(MICs = 1-100 μg/ml). Flumequine is also active against field isolates of B. hyodysenteriae (MICs = 6.25-200 μg/ml).2It inhibits DNA gyrase, disrupting supercoiling of bacterial DNA to block transcription and replication.3In vivo, flumequine (50 mg/kg) increases survival in rat models ofP. vulgaris-induced urinary tract infection andP. mirabilis-induced prostatitis.1Formulations containing flumequine have been used in the treatment of urinary tract infections in veterinary medicine. 1.Rohlfing, S.R., Gerster, J.R., and Kvam, D.C.Bioevaluation of the antibacterial flumequine for urinary tract useAntimicrob. Agents Chemother.10(1)20-24(1976) 2.Aller-Morán, L.M., Martínez-Lobo, F.J., Rubio, P., et al.Evaluation of the in vitro activity of flumequine against field isolates of Brachyspira hyodysenteriaeRes. Vet. Sci.10351-53(2015) 3.Smith, J.T.The mode of action of 4-quinolones and possible mechanisms of resistanceJ. Antimicrob. Chemother.18 (Suppl. D)21-29(1986)

Rasagiline-13C3is intended for use as an internal standard for the quantification of rasagiline by GC- or LC-MS. Rasagiline is an inhibitor of monoamine oxidase B (MAO-B; IC50= 4.43 nM for the rat brain enzyme).1It is selective for MAO-B over MAO-A (IC50= 412 nM for the rat brain enzyme). It inhibits serum and NGF withdrawal-induced apoptosis of PC12 cells when used at concentrations ranging from 0.01 to 100 μM.2Rasagiline inhibits rat brain MAO-Bin vivo(ED50= 0.1 mg/kg).1It reduces cerebral edema in a mouse model of traumatic brain injury.2Rasagiline (0.1 mg/kg) reduces cortical and hippocampal levels of full-length and soluble amyloid precursor protein (APP) in rats and mice. It also reduces α-synuclein-induced substantia nigral neuron loss and improves motor dysfunction in a mouse model of Parkinson's disease.3Formulations containing rasagiline have been used in the treatment of Parkinson's disease. 1.Youdim, M.B.H., Gross, A., and Finberg, J.P.Rasagiline [N-propargyl-1R(+)-aminoindan], a selective and potent inhibitor of mitochondrial monoamine oxidase BBrit. J. Pharmacol.132(2)500-506(2001) 2.Youdim, M.B.H., and Weinstock, M.Molecular basis of neuroprotective activities of rasagiline and the anti-Alzheimer drug TV3326 [(N-propargyl-(3R) aminoindan-5-YL)-ethyl methyl carbamate]Cell. Mol. Neurobiol.21(6)555-573(2001) 3.Kang, S.S., Ahn, E.H., Zhang, Z., et al.α-Synuclein stimulation of monoamine oxidase-B and legumain protease mediates the pathology of Parkinson's diseaseEMBO J.37(12)e98878(2018)