Clinical pharmacology is the science of drugs and their clinical use. It is underpinned by the basic science of pharmacology, with added focus on the application of pharmacological principles and quantitative methods in the real world. Clinical pharmacology connects the gap between medical practice and laboratory science. The main objective is to promote the safety of prescription, maximize the drug effects and minimize the side effects. It is important that there be an association with pharmacists skilled in areas of drug information, medication safety and other aspects of pharmacy practice related to clinical pharmacology. An adverse effect may be termed a "side effect" when judged to be secondary to a main or therapeutic effect. A drug interaction is a situation in which a substance affects the activity of a drug when both are administered together. This action can be synergistic or antagonistic or a new effect can be produced that neither produces on its own. Drug development is the process of bringing a new pharmaceutical drug to the market once a lead compound has been identified through the process of drug discovery. It includes pre-clinical research on microorganisms and animals, filing for regulatory status, such as via the United States Food and Drug Administration for an investigational new drug to initiate clinical trials on humans, and may include the step of obtaining regulatory approval with a new drug application to market the drug.