Drug development is the process in which, once a lead compound has been identified through different processes, a new drug comes into the market. Drug design is often referred to as rational drug design or simply rational design, where understanding of a biological target is the basis of the method of looking for new drugs. The drug is a small organic molecule that plays a role in activating or inhibiting the function of a biomolecule such as a protein, resulting in a therapeutic advantage to the function of a biomolecule such as a protein. Drug design essentially requires the design of molecules that are complementary to the biomolecular target with which they can interact in shape & charge and will therefore bind to it. A generic drug is a drug which is similar to a brand-name product in dosage, consistency, efficiency, power, route of administration, and intended of usage. The preclinical development starts in the phases of drug development research before clinical trials can begin and during which essential feasibility can be initiated.