Introduction
It is divided into different stages which must be met to ensure the drug's
approval. These include;
1.Discovery and development stageDiscovery and development stage.
Refers to the initiation process of the whole process of drug discovery and
development.
It is divided into different sub-stages which include;
Identification of target.
A target, according to biological terms refers to a scope of biological units which are proteins, genes, and RNA. For the target to be identified, data mining is involved in that data is collected from sources as publications, proteomics, gene expressions, patent information, MRNA examinations, and compound profiling data to ascertain if, the given target is expressed in disease progression.
Also, characteristic screening may be done to spot disease-fitting targets.
Validation of target.
Once spotted, the target needs full investigation. Validation tools such as antisense technology, transgenic animals, monoclonal antibodies, and chemical genomics are used.
Identification of Hit.
A hit refers to a compound that has the required activity in a compound screen and whose activity is validated upon re-testing.
Different screening technologies such as high throughput screening, focused screening, fragment screening, and physiological screening are used to locate molecules that interact with the drug target.
Development of assays and screening.
Investigative and qualitative procedures are laid down to examine a compound's effect on identified molecular, and cellular targets which are tissue receptors, hormones, enzymes, nuclear receptors, DNA, and ion channels.
Biochemical and cellular-based assays are used to recognize compounds that meet the characteristic action for the drug target.
Hit to lead phase.
As discussed earlier, a hit refers to a compound that observes the required activity in a compound screen and whose activity is validated upon re-testing. Lead refers to the product obtained after the screening process.
The objective of this phase is to identify the most favored postulant that associates with the drug objective.
These postulants are known as leads and are usually enhanced to boost the quality of their function.
Lead enhancement.
The main aim is to preserve the required quality of the drug's main constituents while minimizing any shortfalls in its structure.
During this phase, in, vivo pharmacokinetics studies are conducted to provide data that will be screened by high throughput DMPK screening in vitro tests.
After this phase, only those compounds that will be graded will continue with the other investigative procedures before being termed as pre-clinical postulants.
Pre-clinical research
This is the second stage after discovery. Experiments are conducted to examine the action and toxicity of the new compound. At this point, in vivo and in vitro testing are done.
Here, experiments are conducted with animals by giving them an increasing dosage of the new compound time after time to observe their response.
Other studies done, examine the new compound's ability to treat the targeted disease in animals.
Furthermore, the chosen postulants pass through pharmacodynamics and
pharmacokinetics testing, for evaluation of the drug's functioning on the body and vice versa.
This process follows the FDA's policies on good laboratory practice.
It is only after the drug has passed this phase that it is deemed fit to be tried on humans.
Clinical research
It is at this stage that the drug starts being tried on humans.
Usually divided into four phases, phase 1 involves 20-100 volunteers or those who have the disease, phase 2, involves a larger number than phase 1, and phase 3 involves 300-3000 people with the disease.
Phase 4 involves several thousand people. The success of the drug depends only if it is deemed safe and efficient on humans during clinical trials.
Reviewing by FDA
Reviewing is done by a team of experts who are doctors, chemists,
microbiologists, pharmacologists, and statisticians who go through the drug's
findings produced from clinical trials.
These findings include both negative and positive effects on patients. It is after reviewing that the FDA approves the manufacturing and marketing of the drug.
FDA post-market safety monitoring
At this point, FDA monitors the drug's performance and safety on humans once it is availed to the public.
This is because, during the time of approval, not all information on the drug's safety could have been acquired.
For more information on health related topics visit
Sources
JP Hughes, S Rees, SB Kalindjian, KL Philpott. Principles of early drug
discovery. British journal of pharmacology.
22 November 2010. https://doi.org/10.1111/j.1476-5381.2010.01127.x
Andy Tay, PhD. Principles and
challenges of target-based drug discovery. Technology networks drug discovery.
16 December 2021.
https://www.dotmatics.com/faqs/what-is-hit-to-lead-stage-in-drug-discovery
https://www.patheon.com/us/en/insights-resources/blog/drug-development-phases.html
https://www.fda.gov/patients/drug-development-process/step-5-fda-post-market-drug-safety-monitoring
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