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The Journey of a Drug: From Bench to Bed-side

When you take a Paracetamol or an antibiotic, or any other medicine prescribed by your doctor or the one that you have bought over the counter, have you ever wondered about how that particular drug rightly cures the disease or condition which you consume it for?


Be it a small over-the-counter drug like Paracetamol or something as big as a #covid19 vaccine, all drugs and even medical devices like the pacemaker, catheter, or a surgical suture have to go through a process that ensures the safety and efficacy of the drug. This process easily costs hundreds of millions of dollars to the company and it can take a decade to get the drug approved and reach the market for human consumption.


There are different phases/stages in this drug approval process and each phase has an important submission that is required by the regulatory body. These regulations have been put forth based on the learnings from several medical disasters in the past like the Thalidomide tragedy, the Tuskeegee study, etc.

Deformation in a child: a side-effect of Thalidomide in pregnant women.

The Tuskeegee Experiment

There are 4 Phases in a Clinical Trial Process (Phase 1 - Phase 4). Prior to all these phases, the beginning point of any drug lies at the discovery stage. More than 1000 prospective molecules enter the research and throughout the drug development process, several of these get filtered out on the basis of safety, efficacy, and target identification. In the end, only one receives the approval and reaches the market.

Pre-clinical Phase

A series of experiments are conducted in animals and cell lines in the laboratory to study the preliminary effectiveness, toxicity, pharmacokinetics, and safety information. It is the so-called move from bench to bedside. Varying doses are tested in vitro and in vivo. In silico profiling is also performed using computer models for drug-target interactions. These studies pave the way for the first-in-human trials (FIH).

Phase 0

The First-in-human (FIH) trials also called human microdose studies, have single sub-therapeutic doses given to 10 to 15 subjects and yield pharmacokinetic data or help with imaging specific targets without introducing pharmacological effects. Pharmaceutical companies perform Phase 0 studies to decide which of their drug candidates has the best pharmacokinetic parameters in humans.