ABSTRACT
However, one should not forget that nature has already shown us that small molecules can have sufficient information built into them to achieve specificity as drugs. Consider steroids, leukotrienes, nucleosides, mononucleotides, catecholamines, excitatory amino acids, or even something as simple as acetylcholine (Fig. 10). These are small-molecule messengers acting extra-or intracellularly, or both, and represent drugs with legitimate specificity in terms of their molecular targets. One does not necessarily need a molecular weight of 3000 in a drug to achieve appropriate selectivity or specificity. This provides
continuing impetus that small molecules can, through various approaches, yield the degree of selectivity necessary to achieve the goal of being a drug for a particular disease.
