A clinical trial (also called clinical research) is a research study in humans to answer specific questions. Carefully conducted clinical trials are the fastest and safest way to find treatments that work in people and ways to improve health. Interventional trials determine whether experimental treatments (medications, procedures, or behavioral interventions) or new ways of using known therapies are safe and effective under controlled environments. Observational trials address health issues in large groups of people or populations in natural settings. (These are often called epidemiologic studies.)
A Brief Summary of the Drug Evaluation Process
in the United States
In the United States, approval of a new drug for clinical use follows a series of developmental and evaluative steps under an Investigational New Drug (IND) Application, which precedes submission of a New Drug Application (NDA) for marketing approval from the Food and Drug Administration (FDA). The process is divided into preclinical and three clinical, investigational phases followed by NDA review by the FDA.
Vitamins are essential to life. Diseases such as scurvy occur when vitamin C intake is inadequate; bone disease such as rickets or osteoporosis occur when vitamin D intake is inadequate; anemias occur when vitamin B levels are inadequate; deficiency of folic acid during pregnancy can lead to fetal neural tube defects; and bleeding disorders occur when vitamin K levels or intake are inadequate.