The Different Phases of a Clinical Trial


If you walk into any pharmacy today, you are going to come across a very wide range of medicines. Some of these, you can buy over the counter, while a doctor’s prescription may be required for others. Some are generic, while others are from the original manufacturers. Some have been around for many years, while others have only just recently made it to the shelves. For any new medicine to be approved for distribution to the public, it must undergo various stages of approval, including a lengthy series of clinical trials. The nature, objectives, and outcomes of these clinical trials are looked at in more depth.

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Defining a Clinical Trial

With so many persistent new and old medical conditions, medical practitioners need a wide selection of pharmaceutical products to select from. These may be used to prevent, treat, diagnose, or alleviate different medical conditions. Before a medicine can be approved for use by humans, extensive clinical research must be done on the proposed new drug.

In medical laboratories around the world, researchers are creating new medications. These research hubs may be at academic institutions, government facilities, pharmaceutical companies, or specialized research centers. Ideas about new medicines are first tested out on a small scale, and these could use mice as test subjects. Getting positive results at this stage is only the beginning. The field of clinical research is all about looking at the safety and efficiency or efficacy of new drugs meant for use by human beings.

Clinical trials are lengthy observations and experiments run on new medicines with human test subjects. They are five different phases to clinical trials to generate the data, which can prove whether a new drug is safe to use and can do what it claims. Clinical trials are very expensive. They can take many years to complete and can involve more and more participants at each stage. There can be no shortcuts when it comes to getting a new medication approved.

The Phases of a Clinical Trial

The five phases of a clinical trial offer an opportunity for the trial owner to test and prove different aspects of the new product. Phase 0 of a clinical trial is aimed at looking at how a drug functions in the human system. The dissolution, absorption, and chemical interactions the drugs make when taken orally or otherwise taken in are studied in the fields of pharmacodynamics and pharmacokinetics. This set of initial trials is optional.

In Phase 0, a small group of 10-15 people is given a single dose of the study drug. Preliminary data about how the drug works in the body is gathered. This includes absorption into the blood system, distribution, metabolism of the drug in the body, and the drug’s excretion from the body.

In Phase I of a clinical trial, the study drug or treatment is screened for safety. A group of about 20-80 people is tested. The information gathered in this phase relates to how safe the drug is for human, what the safe dosage ranges are, and what the potential side effects could be.

In Phase II, the goal is to determine the preliminary efficacy of the drug. Usually, the drug is compared with a placebo to see how well it works. A group of 100-300 human test subjects is involved in this phase. Further investigation of the safety of the drug is also done.

Phase III is done to do a final confirmation of the safety and efficacy of the new drug. A much larger group of up to 3,000 people is required to gather further data and compare with existing treatments. After the drug is approved, Phase IV is done as an ongoing test on the drug’s use.

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