(+-)-Verapamil-d3 (hydrochloride)

(+-)-Verapamil-d3 (hydrochloride) (Item No. 18452) is intended for use as an internal standard for the quantification of verapamil (Item No. 14288) by GC- or LC-MS. Verapamil is the prototypical blocker of L-type calcium channels that produces excitation-contraction uncoupling in cardiac muscle by preventing the slow-inward current of calcium ions.{22485} Verapamil can also block calcium fluxes in vascular smooth muscle. It has both peripheral and coronary vasodilator effects (IC50 = 0.38 ?M in guinea pig aortic strip) and has been used to control hypertension, angina, cardiac arrhythmia, and vascular headaches.{22481,22479,22478} Verapamil has also been used in cell biology as an inhibitor of drug efflux pump proteins such as P-glycoprotein, which are often over-expressed in certain tumor cell lines.{20755}