Clinical trials are scientific examination that evaluates safety and efficacy of different therapies in human subjects. Meinert coined as the research activity that involves the administration of a test treatment to some experimental unit in order to evaluate the treatment. The code of federal regulations (CFR) defined as clinical investigation of a drug that is administrated in to diverse human subjects. The three important keywords are experimental unit, treatment along with evaluation. Clinical trials types are treatment trails, preventive trails, diagnostic trails, screening trails and quality of life trails.
The different phases of clinical trials involve pre-clinical trials, phase -1, 2, 3, 4 trails. A pre-clinical trial which involves invitro experiments with wide range of doses of the study drug to obtain preliminary efficacy, toxicity and pharmaceutical information. Phase -1 clinical trials are used to determine the metabolism and pharmalogical action of drugs in humankind and the side effects with the increasing doses and effectiveness. Phase -2 trials is used to estimate the effectiveness of the drug for a particular indication with the disease condition under study and determine the common short term side effects and risks. Phase-3 is expanded controlled and uncontrolled trails after preliminary evidence suggesting the effectiveness of the drug. Phase -4 is for post marketing studies to delineate additional information concerning the drug’s risks, benefits and optimal use.
Steps involved in pre-clinical trials are identifying a drug target, developing a bioassay, screening the drug in a Bioassay, establishing effective and toxic doses and filing for an approval as a investigational new drug(IND). Phase -1 clinical trials are earliest trails in a life of a new drug or treatment. These trails are designed to obtain safety, tolerability, pharmacokinetics and pharmacodynamics.
Types of phase -1 trials are single ascending dose, multiple ascending dose and food effect. Phase 2 clinical trials are controlled experimental studies conducted to evaluate the effectiveness of the drug for a particular indication in patients with the disease or condition under study and to find out the common short-term side effects and risks. An important goal for this phase is to decide the dose(s) and regimen for Phase III trials. Phase III Clinical Trials are considered to start with the initiation of studies in which the main primary objective is to demonstrate, or confirm therapeutic benefit. Phase III trials are the most expensive, time-consuming and difficult trials to design and run, mainly in therapies for chronic medical conditions. Phase IV Clinical trial is also known as Post Marketing Surveillance Trial. Phase IV trials are the safety surveillance (Pharmacovigilance) and ongoing technical support of a drug after it receives permission to be sold.