ABSTRACT
The development of modem medicines is by and large the search for more and more selective agents. Increasingly, this selectivity is obtained by employing screening methods which operate at the molecular level. The successful progression of novel compounds from pharmacological screening through to beneficial therapeutic usage requires not only that a compound exhibit selectivity at the in vitro level, but that in vivo it will distribute to its site of action. Knowledge gained on the distribution of a compound within the intact animal will invariably provide a background of useful information on which to base examination of the pharmacological or toxicological nature of the compound. This information will be of value irrespective of whether the compounds be pharmaceuticals, food additives, pesticides, or industrial chemicals.
