THE ROLE OF RECEPTOR-BINDING IN DRUG DISCOVERY

Radioligand receptor binding has been used extensively to identify and characterize a host of receptors and enzymes targeting virtually ever y therapeutic area. Many drug discovery programs have been based on th e utilization of radioligand receptor binding technology to identify l ead compounds which interact with receptors likely to be important in neuronal, immunological, gastrointestinal, and cardiovascular function /dysfunction. There are several obvious advantages to using in vitro r eceptor binding as a first level screen when compared to in vivo pharm acometric screens. Scientifically, the structure activity data generat ed in binding assays is a direct reflection of the ligand/receptor int eraction minus the complications which result from secondary events, b ioavailability, and pharmacodynamic issues. Technically, the binding s tudies require only a small amount of test compound (less-than-or-equa l-to 1 mg), while whole animal studies routinely need gram quantities. Similarly, only a small amount of tissue is required, compared with t he cost of purchase and maintenance of live animals for in vivo screen ing. Supply and labor costs are drastically reduced due to the limited volume and test tube based technology of receptor binding. For these reasons receptor binding assays have been utilized with considerable s uccess to discover site specific lead compounds in virtually every the rapeutic area.