Pharmacodynamic and metabolism studies on a new coronary vasodilator, N-(2-hydroxyethyl) nicotinamide nitrate (SG-75)

Pharmacodynamics and metabolism of N-(2-hydroxyethyl) nicotinamide nitrate (SG-75) were investigated in rats in relation to its main metabolic product. When SG-75 was orally administered, SG-75 and SG-86, a denitrate compound of SG-75, appeared in the blood. Within 7 yr, approximately 60% of the administered SG-75 were recovered in the urine as SG-86. When administered intraduodenally, SG-75 was rapidly absorbed and transferred in an unaltered form into the portal vein. SG-75 possessed hypotensive and coronary vasodilating actions, while SG-86 had little effect on the cardiovascular system. The coronary vasodilating effects of SG-75 k(0.3-20 micrograms i.a.) were unaffected by the continuous infusion of SG-86 into the coronary perfusion system, even in large doses (50 micrograms/min, or 500 micrograms/min).