Medicines General anaesthetics

Commonly used solvent in chemical laboratories and in the chemical and pharmaceutical industries mainly used as an extractant for fats, oils, waxes and resins used for the manufacture of munitions, plastics, perfumes used in medicine as a general anaesthetic. 

The oxidative metabolism leads to the formation of reactive species (epoxides, quinone-imines, etc.), which can be a source of toxicity. Consequently, slowing down or limiting these oxidations is an important second target in medicinal chemistry. Thus, the metabolism of halothan (the first modern general anaesthetic) provides hepatotoxic metabolites inducing an important rate of hepatitis the oxidation of the non-fluorinated carbon generates trifluoroacetyl chloride. The latter can react with proteins and lead to immunotoxic adducts [54], The replacement of bromine or chlorine atoms by additional fluorine atoms has led to new families of compounds, preferentially excreted by pulmonary way. These molecules undergo only a very weak metabolism rate (1-3%) [54,55]. 

It might seem strange to consider such a compound for medicinal use, but at the right dose levels and under proper control, there are very useful applications for this sort of action. The main application is in the relaxation of abdominal muscles in preparation for surgery. This allows the surgeon to use lower levels of general anaesthetic than would otherwise be required and therefore increase the safety margin for operations. 

Vinyl groups are not excessively used in medicinal chemistry. Divinyl oxide is an excellent general anaesthetic but it polymerizes easily and forms peroxides. Stabilization of the compound is usually achieved by addition of 0.01% of Al-phenyl a-naphtylamine. On the other hand, compounds such as kainic acid, vinylbital, quinine, 17a-vinyl-testosterone, compound SKF 1(XX)47, and vigabatrin (Fig. 19.22) are perfectly stable vinyl derivatives. 

TC Daniels and EC Jorgensen General Anaesthetics. In Textbook of Organic Medicinal and Pharmaceutical Chemistry (Eds) (CO Wilson), 0 Gisvold and RF Doerge) JB Lippincott Philadelphia, (1977). 

Depressants may be hydrocarbons, halogenated hydrocarbons, alcohols, ethers, ketones, weak acids (like the barbiturates), weak bases, or sulphones. They are the selectively toxic agents used in medicine as hypnotics and general anaesthetics. This is the only kind of biological activity in which structure simply does not matter (there is much more about this in Chapter 15). See Section 3.3 for the general function of partition effects in securing selective distribution of drugs. 

Bovill J G 2000 Mechanisms of anaesthesia time to say farewell to the Meyer-Overton rule. Current Opinion in Anaesthesiology 13 433-436 Carter A J 1999 Dwale an anaesthetic from old England. British Medical Journal 319 1623-1626 (use of medicinal herbs to render a patient unconscious for surgery, before modem general anaesthesia)... 

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