Consider the last time you took medication, whether it was a pain reliever or cough syrup. What were you thinking about while you ingested the medicine? You probably weren't thinking about the drug's origins, but scientists and physicians have undoubtedly spent countless hours creating it.
The process of obtaining medication from your local pharmacy is complicated, time-consuming, and sometimes costly. Pharmaceutical firms have sophisticated business models for researching, developing, and manufacturing molecules to cure illnesses. The initial phase of drug development consists of laboratory research to identify and refine the medicine, followed by clinical trials to evaluate patients' safety and efficacy.
Despite technical improvements, fewer new medications are authorized each year.
Many of the medications created in the previous century were derived from naturally occurring molecules (natural products) found in plants, bacteria, and fungus; as the discovery of these treatments slowed, artificial molecules have not filled the void. The challenge for medical science is to meet the growing need for novel medications.
Phase One: Drug Discovery
The discovery of new drugs is dependent on the combined efforts of researchers such as chemists, biologists, and physicians. Chemists create chemicals that may one day become medicines, whereas biologists look into the molecules that cause illnesses. Scientists collaborate to identify therapeutic targets in the form of big macromolecules (such as proteins) or cancer cells and then look for compounds that will disrupt the protein or kill the cancer cell. Chemistry is important because of its capacity to interpret molecular interactions, which dictate how medicines heal illnesses.
In some ways, drug development is analogous to looking for a molecular key (the medication) to unlock the disease's lock. Scientists attempt to learn as much as they can about the structures of the key and lock and how various keys interact with the lock. The molecular key must be complementary in its geometric shape and interactions with a cavity in the biomolecule to have a good match and inhibit the drug target's function. The problem is to devise a method for testing the huge number of available keys against the vast number of accessible locks. Not every illness has a lock to make matters even more complicated, and one key may fit into many locks.
Historically, medications were given in herbal mixtures, and many traditional medicines are still given in this manner. Chemists could extract active chemicals from natural sources as technology improved, allowing them to create more effective medications. For example, aspirin (acetylsalicylic acid) was identified in the willow tree bark, which was previously employed in traditional herbal medicines.
When a natural supply is unavailable, a chemical frequently comes in to give viable substitutes. The Pacific yew tree (Taxus brevifolia) was discovered to generate the blockbuster anticancer medicine paclitaxel (Taxol) in the early 1960s. Initially, Pacific yew numbers fell because the harvesting method removed the bark from the trees, killing them. The public uproar against this approach resulted in a better process that produced paclitaxel by extracting a portion of the molecule from European yew needles and then chemically modifying it to make the entire medication. Paclitaxel is now manufactured by extracting plant cells from twigs and needles and cultivating the cells in a process known as plant cell fermentation; this method is more environmentally friendly because it saves trees and lowers chemical waste.
The initial stage in contemporary drug development is generally a technique known as high-throughput screening. Thousands of compounds are evaluated for effectiveness against a specific therapeutic target at the same time . Researchers in this technique use robots to combine small quantities of prospective medicines with tiny samples of the drug target. Artificial molecules, as well as natural materials, might be included in the collection of test molecules. During the screening phase, a chemical may demonstrate therapeutic potential by binding to the target biomolecule (the key to the lock) or killing sick cells. An effective molecule discovered in this manner is then developed into a potential drug by screening with variations of the initial molecule. Whether a more powerful medication is discovered, the molecule is examined in cells and animals to see if it can imitate the drug's behavior in people. If the medication is found to be beneficial in laboratory testing, a clinical trial will be conducted.
Phase Two: Clinical Trials
Clinical trials are the stage of drug development in which the effect of a medication on humans is evaluated . Because the human body is more complicated than a laboratory cell, medication must be researched in a small group of patients before being approved for distribution to the general public by the US Food and Drug Administration (FDA). A set of chemical structure-based predictions was constructed to foresee a molecule's "drug-likeness." Though these metrics are not required, they can estimate how the medication behaves in the body (e.g., toxicity) and how the body reacts to the molecule (e.g., metabolism, absorption). In clinical trials, the medicine is largely evaluated for how well it treats the condition it is intended to treat and if it is safe for patients to use. Often, billions of dollars have already been invested in a medication's discovery and development at this stage; this massive expenditure is a significant component of the inherent financial risk in drug development.
Occasionally, a drug's intended purpose is not its most effective function. Sildenafil (Viagra), for example, was originally designed to treat high blood pressure (hypertension) and chest discomfort (angina) . When Viagra was in its initial clinical trial, people began requesting the medicine, although the studies had revealed that it was useless for treating angina. Another clinical trial was conducted to investigate Viagra's effects on erectile dysfunction, and Viagra eventually became the billion-dollar medication today.