Nitroglycerin

Nitroglycerin (NG), also known as nitroglycerine, trinitroglycerin, trinitroglycerine, or nitro, is more correctly known as glyceryl trinitrate or more formally: 1,2,3-trinitroxypropane. It is a heavy, colorless, oily, explosive liquid most commonly produced by treating glycerol with white fuming nitric acid under conditions appropriate to the formation of the nitric acid ester. Chemically, the substance is an organic nitrate compound rather than a nitro compound, but the traditional name is often retained. Since the 1860s, nitroglycerin has been used as an active ingredient in the manufacture of explosives, mostly dynamite, and as such it is employed in the construction, demolition, and mining industries. Similarly, since the 1880s, it has been used by the military as an active ingredient, and a gelatinizer for nitrocellulose, in some solid propellants, such as Cordite and Ballistite.

Nitroglycerin is also a major component in double-based smokeless gunpowders used by reloaders. Combined with nitrocellulose, there are hundreds of (powder) combinations used by rifle, pistol, and shotgun reloaders.

For over 130 years, nitroglycerin has been used medically as a potent vasodilator to treat heart conditions, such as angina pectoris and chronic heart failure. Though it was previously known that these beneficial effects are due to nitroglycerin being converted to nitric oxide, a potent vasodilator, it was not until 2002 that the enzyme for this conversion was discovered to be mitochondrial aldehyde dehydrogenase.[2] Nitroglycerin is available in sublingual tablets, sprays, and patches.[3] Other potential suggested uses include adjunct therapy in prostate cancer.

Glyceryl trinitrate

Glyceryl trinitrate (GTN) is an alternative name for the chemical nitroglycerin, which has been used to treat angina and heart failure since the experiments of William Murrell were widely reported in 1879. Despite this history, the mechanism of nitric oxide (NO) generation from GTN and the metabolic consequences of this bioactivation are still not entirely understood.

It is useful in decreasing angina attacks, perhaps more so than reversing angina once started, by supplementing blood concentrations of nitric oxide, also called endothelium-derived relaxing factor, before the structure of the nitric oxide as the responsible agent was known. This led to the development of transdermal patches of glyceryl trinitrate, providing 24-hour release. However the effectiveness of glyceryl trinitrate is limited by development of tolerance/tachyphylaxis within 2–3 weeks of sustained use. Continuous administration and absorption (such as provided by daily pills and especially skin patches) accelerate onset of tolerance and limit the usefulness of the agent. Thus glyceryl trinitrate works best when used only short term, pulse dosing. Glyceryl trinitrate is useful for acute myocardial infarction (heart attack) and pulmonary edema,[citation needed] again working best if used quickly, within a few minutes of symptom onset, as a pulse dose.[citation needed] It may also be given as a sublingual or buccal dose in the form of a tablet placed under the tongue or a spray into the mouth for the treatment of an angina attack.