The development of a drug has 5 stages until it becomes accessible to the patients. The first stage is the discovery and development, in this first part of the process many substances possess a great poise to become a medical treatment, and however, after some test only a few are approved for phase two. In the second stage also called preclinical researchers need to find out if substances have a potential cause of damage, the test is also called toxicity and can be performed in vitro or in vivo, normally preclinical studies are not long lasting, but the studies should show information on levels of toxicity and then whether the substance can be tested in humans. The third phase of drug development, Clinical Research, refers to the study and trials that are done on humans, at this point in the development the researchers organize a study plan called protocols and elaborate questions and objectives that they intend to respond for example, how many people have been part of the study or how the drug will be passed on to patients and in which dosage. The complete process can take about ten years, thus following the fourth phase where a review of all the steps of the drug is carried out, finishing in the fifth phase, which is the Post-Market Drug Safety Monitoring where the drug is already accessible to the consumer, but monitoring to be continued.