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Mandesh Institute of Pharmaceutical Science and Research Center, Mhaswad, Dr. Babasaheb Ambedkar Technological University, Lonere, Raigad MS India - 415509
Clinical trials are carefully conducted research studies involving human volunteers. They are done to answer specific health-related questions. Clinical trials help determine if a treatment or therapy is safe and effective. These studies are carried out in a suitable and controlled environment. Clinical trials are also used to test the effectiveness of a drug or substance through biological testing. There are five main phases in clinical trials: Phase 0, Phase I, Phase II, Phase III, and Phase IV.Clinical trials play an important role in drug discovery. They help find out how well a drug works. Today, clinical trials are necessary before a new drug can be released to the market. In clinical trials, data is collected by testing on humans or animals through biological studies. This review aims to discuss the different phases of clinical trials. Clinical trials are essential for evaluating the safety, efficacy, and overall impact of new drugs, medical devices, and therapeutic approaches before they are made available to the public. These studies are conducted in a phased manner, beginning with preclinical testing in laboratory and animal models, followed by human trials across four distinct phases. Each phase serves a specific purpose?from understanding basic pharmacological properties in Phase 0 and assessing safety in Phase I to evaluating effectiveness in Phase II, confirming benefits and monitoring risks in Phase III, and observing long-term effects post-approval in Phase IV. Clinical trials follow strict international guidelines, such as the ICH-GCP (International Conference on Harmonisation ? Good Clinical Practice), to ensure ethical standards, scientific rigor, and participant safety. Various trial types and designs, including treatment, diagnostic, and screening trials, as well as open-label and blinded studies, are used based on research goals. Together, these trials contribute significantly to medical innovation, improved healthcare outcomes, and the development of evidence-based treatments.
Clinical trials are studies done to check how safe and effective a new drug or medical device is when used on people. These trials are usually done only after enough basic information about the drug has been collected. [3] Before testing a drug in people, it must go through pre-clinical studies. These include in vitro (lab tests using cells or tissues) and in vivo (tests on animals). These early studies help researchers understand how well the drug works and how it behaves in the body (its pharmacokinetics). Currently, there are two main international guidelines that researchers follow to ensure clinical trials are done properly and ethically. [1][5] The main goal of clinical research is to bring new, effective, and safe medicines to the market to improve human health. In this process, drugs are first tested on animals and then, if they are found to be safe, tested on people. Clinical trials play a vital role in the advancement of medical science and the development of new treatments. These carefully designed research studies are conducted to evaluate the safety, efficacy, and potential side effects of medical interventions, including drugs, medical devices, and therapeutic procedures. Before any new treatment becomes widely available, it must undergo rigorous testing through clinical trials to ensure that it meets the necessary standards for patient care. [2] The significance of clinical trials extends beyond individual therapies; they contribute to the broader understanding of diseases and help improve healthcare outcomes on a global scale. With the increasing complexity of modern medicine, clinical trials have evolved to incorporate innovative methodologies, ethical considerations, and regulatory guidelines. This review aims to provide a comprehensive overview of clinical trials, focusing on their design, phases, ethical frameworks, challenges, and their critical role in evidence-based medicine.
Preclinical studies -
Pre-clinical studies, also called in vitro studies, are tests done in labs, usually on animals. [1] These studies help check the purity, production process, and how the drug works in the body (pharmacokinetics and pharmacodynamics). Pre-clinical trials are done before testing the drug on humans in clinical trials. They help pharmaceutical companies find out if the drug has any medical benefits. These studies also show if any changes need to be made to the drug before moving forward with development. [3]
Phase 0-
Phase 0 is a new step added before the main clinical trials. It is designed as an early test, following guidelines from the U.S. Food and Drug Administration (FDA). [1] In Phase 0, a very small dose of the drug is given to a small group of people (about 10 to 15) to collect preliminary information. This phase does not provide full details about the safety or effectiveness of the drug. [3]
a) Understanding how the drug moves through the body (pharmacokinetics).
b) Learning how the drug works (mechanism of action).
c) Finding the right dose that shows some effect (significant dose determination). [2]
The main goal of a Phase 0 trial is to understand how a drug is absorbed, distributed, metabolized, and excreted in humans—collectively known as pharmacokinetics. Additionally, researchers may study how the drug interacts with its target (pharmacodynamics). These trials help determine whether the drug performs as expected based on laboratory and animal studies.
Sandesh Dhadambe*, Anish Mane, Suraj Chavan, Snehal Pise, A Comprehensive Review on - Clinical Trails, Int. J. Sci. R. Tech., 2025, 2 (10), 329-334. https://doi.org/10.5281/zenodo.17373531
10.5281/zenodo.17373531