ABSTRACT
New Drug Development is a program of preclinical research and conducted with the objective of selecting new drugs for the treatment of diseases, for example, cancer. In a Drug Development Program, screening is usually done by applying sequential screens: the "primary screen" should ideally be sensitive, simple and selective, and cost and time efficient. In 1955, the U. S. National Cancer Institute (NCI) initiated a large-scale screening program for the discovery of new anticancer drugs. A variety of test models is being used in preclinical drug evaluation, which can be divided into in vitro test systems and in vivo test systems, using tumor material of murine or human origin. Anticancer drugs are powerful pharmacological tools with an extremely narrow therapeutic index: biologically inactive doses may be within one log of lethal doses. The ultimate goal of each drug development program is to determine the clinical effectiveness of a new drug.
