ABSTRACT
Since late 1980s, the drug discovery and development process has undergone significant changes, particularly in the preclinical stage involving drug candidate selection, drug metabolism and safety studies. These changes are directly related to the scientific progress in research areas of combinatorial chemistry, recombinant DNA technology, toxicology, metabolism, and analytical instrumentation. The increasing availability of tissues, cell cultures, and drug-metabolizing enzymes from human sources has led to the increased use of in vitro studies to select the most desirable drug candidates. Well executed in vitro studies can provide valuable information regarding the metabolic fate of a new drug in humans, critical factors contributing to the variability of pharmacokinetic parameters, and the potential for drug-drug interactions. Consequently, in vitro study results are now being routinely included in New Drug Applications (NDA) by the sponsors.
