149934-16-7

9-Nitrominocycline is used as a reagent in the preparation of tigecycline from minocycline hydrochloride.

Minoxidil (Loniten) is an orally effective vasodilator. It is more potent and longer acting than hydralazine and does not accumulate significantly in patients with renal insufficiency. It depends on in vivo metabolism by hepatic enzymes to produce an active metabolite, minoxidil sulfate. Minoxidil sulfate activates potassium channels, resulting in hyperpolarization of vascular smooth muscle and relaxation of the blood vessel.

Peak concentrations of minoxidil in the blood occur 1 hour after oral administration, although the therapeutic effect may take 2 or more hours to manifest. This is probably related to the time it takes to convert minoxidil to minoxidil sulfate. The antihypertensive action after an oral dose of minoxidil lasts 12 to 24 hours. The long duration of action allows the drug to be administered only once or twice a day, a regimen that may be beneficial for compliance. Interestingly, the therapeutic half-life is considerably longer than the plasma half-life. This may be, as has been suggested for hydralazine, a result either of accumulation of the drug and its active metabolite in arterial walls or a longer plasma half-life of the sulfated metabolite, or both.
The ultimate disposition of minoxidil depends primarily on hepatic metabolism and only slightly on renal excretion of unchanged drug. Because of this, pharmacological activity is not cumulative in patients with renal failure.