Clinical research could be a branch of tending science that determines the security and effectiveness (efficacy) of medicines, devices, diagnostic product and treatment regimens supposed for human use. These is also used for interference, treatment, identification or for relieving symptoms of a illness. Clinical research is completely different from clinical practice. In clinical practice established treatments are used, whereas in clinical research evidence is collected to determine a treatment. The term "clinical research" refers to the whole listing of a drug/device/biologic, really any check article from its beginning within the workplace to its introduction to the buyer market and on the far side. Once the promising candidate or the molecule is known within the workplace, it's subjected to pre-clinical studies or animal studies wherever completely different aspects of the check article (including its safety toxicity if applicable and effectiveness, if doable at this early stage) area unit studied. Clinical trials involving new medicine area unit ordinarily classified into four phases. every part of the drug approval method is treated as a separate clinical test. The drug-development method can usually proceed through all four phases over a few years. If the drug with success passes through Phases I, II, and III, it'll typically be approved by the national administrative unit to be used within the general population. clinical test is 'post-approval' studies. Phase I includes twenty to a hundred healthy volunteers or people with the disease/condition. This study generally lasts many months and its purpose is safety and dose. phase II clinical trial includes a bigger range of individual participants locomote 100-300, and phase III includes close to|some|roughly|more or less|around|or so} 1000-3000 participants to gather additional information about the drug.