The recent debate in Hamilton over fluoridation of the water supply has resulted in a lot of misinformation about fluorine and fluoride. Elsewhere, however, fluorine is playing an important role the development of new pharmaceuticals.
However, before I get on to discussing the use of fluorine in pharmaceuticals, let’s clarify a few points, particularly about the different between fluorine and fluoride.
Fluorine, is both an element and a molecule. As an element (F) it is the smallest of the highly reactive halogen group on the periodic table. This reactivity means that it cannot readily exist as the element. It can however exist as the gas F2, where two fluorine atoms have joined together to stabilise each other. Fluorine gas (F2) is a toxic and corrosive gas.
Fluorine can also form a stable compound with metals, for example, NaF (sodium fluoride). Such compounds are referred to as ionic compounds/salts, where the fluorine atom has gained a negative charge, existing as F– (fluoride). In this form it has very different properties to F2, for example, it is a solid rather than a liquid, is able to strengthen tooth enamel, and is far less toxic than F2.
Fluorine can also be attached to carbon atoms in organic molecules, including drugs, to produce new molecules with interesting properties. The carbon-fluorine bond tends to be very strong, and is able to introduce some new properties to drugs. For example, it can increase their fat solubility (allowing them to better cross cell membranes). It can also alter the 3-D shape of a drug, allowing it to better bind to receptors in the body.
At a recent medicinal conference in April, the structures of five new drugs were revealed – three of which contain fluorine. Over the past decade there has been an increase in the number of drugs containing fluorine, as chemists have become more adept at fluorine chemist.
The new drugs include:
BMS-906024, developed for the treatment of breast, lung and colon cancer, as well as leukaemia. See here for more information.
LGX818, developed for the treatment of melanoma. See here for more information.
AZD5423, developed for the treatment of chronic obstructive pulmonary disease. See here for more information.