PartⅢ Script of the Audiovisual Material
How a Drug Becomes a Drug
Drug research and development aims to prevent or treat diseases.While,as a result,a small pill or capsule seems so simple,the process for developing a safe and effective new drug is anything but...Development can take as long as20 years and cost more than$1 billion.
Like relay race,drug development has several stages and requires some team effort,often involving the government,universities,and pharmaceutical companies to reach the finish line.The process begins with basic research.US government agencies,such as the National Institute of Health,conducts and funds research at laboratories around the world to uncover the fundamental knowledge about the diseases.This research helps identify potential drug targets,usually genes and proteins whose functions are critical to the survival or spread of the disease-causing organisms.Scientists then investigate how they can interfere with these targets to control or eliminate the disease.They may test tens of thousands of chemicals or biological compounds to see if they either inhibit or stimulate a given target.Usually,only a very small percentage of these compounds will have effects on the target.These hits are then rescreened multiple times to confirm the results and further chisel the list of the potential drug candidates.
Researchers look for compounds that interact only with the desired target.If a compound reacts with unrelated target,there is a great chance of adverse side effects.To further minimize this risk,researchers conduct experiments to optimize the compound's absorption,distribution,and metabolism inside the body.These studies help to determine which compounds are safe and effective enough for further testing.(https://www.daowen.com)
With the results from these preclinical studies,drug developers seek permission from US Food and Drug Administration to begin testing the compound in people.If granted,scientists embark three-phase clinical testing process that will determine whether a drug will be approved for public use.Because clinical testing requires substantial investment,it is common for the pharmaceutical companies to play a large role during this stage.
Phase I clinical trial tests the experimental drug in about 20 to 80 healthy adults to evaluate its safety,determine its safe dosage range,and identify side effects.During Phase II,the drug is given to proximately 100 to 300 people,including those with target disease,to get early indications of how the drug is working and further evaluate its safety.Phase IIItrials evaluate the drug in a group of 1 000 to 3 000 people who have the disease.These trials aim to confirm the drug's effectiveness and monitor side effects.They also may compare to most commonly used treatment or to no treatment at all.The large-sized three-phase trials allows the results that are more statistically significant or less likely to have occurred by chance.
If a drug successfully complete Phase III testing,a company will seek permission from FDA to market the compound.Its'application contains data from all the preclinical studies and clinical trials,along with the information that FDA will need to make its decision on the drug's safety,efficacy and quality.If proved,the drug can be manufactured and sold to prevent and treat the disease in question.But the process doesn't stop there.The FAD will continue to monitor the drug's safety and effectiveness for as long as it remains on the market.