While morphological analysis at both the light and electron microscopical levels has been fully exploited in academic research, its potential in biopharmaceutical industry has only been fully appreciated in recent years. The biotechnology industry has been developing highly specialized therapeutic molecules, particularly proteins and peptides that are directed to specific molecular targets. The pace of the development of new therapeutic molecules is expected to increase dramatically in the close future, as the biopharmaceutical community will capitalize on the new targets identified by the Human Genome Project.

An efficient drug discovery and development effort should not only include the characterization of the tissue and intracellular distribution of potential targets, but also establish unambiguously that the therapeutic entities reach their intended targets. It has become apparent in recent years that a comprehensive view of the pharmacological action of drugs must include not only the pharmacokinetic parameters but also the tissue distribution and the cellular localization.