Bupivacaine-d₉is intended for use as an internal standard for the quantification of bupivacaine by GC- or LC-MS. Bupivacaine is a sodium channel blocker and local anesthetic.^1,2It inhibits sodium currents in rat dorsal horn neurons in a concentration-dependent manner and inhibits synaptic transmission in rat sympathetic ganglia, increasing the firing threshold when used at a concentration of 200 nM.^3,4Bupivacaine (10 ?M) blocks cardiac sodium channels in a use-dependent manner and inhibits respiration in cardiac cell mitochondria when palmitoyl-carnitine or acetyl-carnitine are used as substrates (IC₅₀s = 0.78 and 0.37 mM, respectively).^1,5It also reduces thermal hyperplasia in a rat model of sciatic ligation injury when 0.6 ml of a 0.5% solution is administered into the perinerve space, and the duration of this effect is extended by co-administration of the NMDA receptor antagonist MK-801 .²Formulations containing bupivacaine have been used as local anesthetics for surgery, oral surgery, and dental procedures and for anesthetic purposes in research studies using animals.

1.Arlock, P.Actions of three local anaesthetics: lidocaine, bupivacaine and ropivacaine on guinea pig papillary muscle sodium channels (Vmax)Pharmacol. Toxicol.63(2)96-104(1988) 2.Mao, J., Price, D.D., Mayer, D.J., et al.Intrathecal MK-801 and local nerve anesthesia synergistically reduce nociceptive behaviors in rats with experimental peripheral mononeuropathyBrain Res.576(2)254-262(1992) 3.Olschewski, A., Hempelmann, G., Vogel, W., et al.Blockade of Na+ and K+ currents by local anesthetics in the dorsal horn neurons of the spinal cordAnesthesiology88(1)172-179(1998) 4.Tabatabai, M., and Booth, A.M.Mechanism of action of local anesthetics on synaptic transmission in the ratAnesth. Analg.71(2)149-157(1990) 5.Weinberg, G.L., Palmer, J.W., VadeBoncouer, T.R., et al.Bupivacaine inhibits acylcarnitine exchange in cardiac mitochondriaAnesthesiology92(2)523-528(2000)