A drug will usually be developed to treat a specific condition. Therefore, the starting point for the development of a new drug begins with the identification of a chemical or substance (drug target) that plays a role in the proliferation of a disease. Chemists, scientists and pharmacologists are all often involved in the isolating and testing of these targets to determine their role in a disease.
Once a potential drug target has been identified, the stage of testing compounds on it can begin. Each compound tested will interact in a certain way with the target, for better or worse. It is the job of the scientists to analyse these effects and determine whether it is worth moving forward with a certain compound.
For every 5,000 compounds discovered, only 5 will make it to the human clinical trial phases. Of those 5, just 1 will make it to the pharmaceutical counter after years of thorough testing.
A potential drug compound will be first tested on diseased cells to determine its effects. Following approval from the relevant licensing body, the drug can then be tested on animals to get a better idea of its effects against a diseased organism. At this stage, researchers will also be examining the safety of the drug before applying for a licence to test on humans. The preclinical testing phase, as it’s called, could take as long as 3 years to complete.
Once a licence has been granted and the preclinical stage is successful, the drug can then be tested on humans. The first phase involves observing healthy volunteers. A typical study at this stage will include between 20 and 30 subjects. The aim of this first human trial is to determine safe dosages, how best to administer the drug, how it is metabolised and how long the effects of the drug last. This stage can take a year to complete.
The second phase involves a greater number of volunteers who, this time, suffer from the targeted disease. The main purpose of this phase is to pinpoint dosage tolerance and drug effectiveness. This phase can last 2 years.
The last clinical trial phase is randomised on a large scale before the data is presented to the relevant licensing authority for approval. Up-to 3,000 volunteers are known to take part in phase 3 trials. It’s common for volunteers in this phase to be asked whether they experience side effects that were documented from the previous phase. This phase can take 3 years to complete.
Once all the relevant licences have been granted, a drug can be manufactured on a large scale. The type of manufacturing process used will depend on the drug and costs. Whichever way a drug is manufactured, the ultimate aim is to manufacture it on a mass scale in a cost-effective way. The process is usually automated with various machines designed to pulverise, mix chemicals and mill. The end products will either be solid (pill or tablet) or liquid (capsule).