The field of drug development is one of the most exciting and crucial scientific areas today. Pharmaceutical innovations drive the discovery and development of new drugs aimed at effective disease treatment. The development process faces numerous challenges: not only efficacy but also safety. Before new drugs can be applied, thorough research and testing are conducted to meet the strictest quality standards. Modern drug development demands synergistic collaboration across various scientific disciplines, which is essential for success. Here, we summarize the key aspects of drug development!
From drug design to discovery
Throughout history, drug discovery has employed various methods and approaches. Traditional drug discovery was based on the ancient knowledge of old civilizations, passed down through generations by shamans, healers, or herbalists. In these traditional methods, experience and intuition played pivotal roles. However, as science advanced, rational methods increasingly took center stage.
Modern rational drug design is founded on the integration of chemistry, physics, and biology. One of the first scientists to represent this approach was Paracelsus, who emphasized the importance of dosage, stating that "everything is poisonous, and only the dose determines whether something is not poisonous". This insight laid the foundation for drug design grounded in scientific principles, with a focus on quantitative data and empirical evidence.
The enlightenment further strengthened this approach. The work of Claude Bernard and Ignaz Semmelweis highlighted the importance of scientific evidence, establishing a mindset that emphasizes the use of scientific methods in every phase of drug development.
However, rational drug design is not only built on the integration of scientific fields. Intuition and serendipity also play roles in several instances. Similarly, discovering new applications for existing drugs is a significant aspect of modern drug development.
The circumstances of drug development
The complex process of drug development involves multiple players. Pharmaceutical companies, university research institutes, and private laboratories all actively participate in research and development projects. The R&D activities entail significant costs, not to mention the time required for the entire process.
When selecting diseases to target, companies often make decisions based on market strategies. They do not always focus on diseases that affect the most people, but rather those with the greatest market potential. Consequently, drug research often concentrates on the problems of the developed world, such as migraines, depression, or cancer. In contrast, diseases prevalent in the developing world, such as tropical diseases, receive less attention unless they begin to impact the populations of the developed world.
Rational approaches to drug design
Rational drug design employs various strategies depending on the available information. System-based strategies examine cells or higher organizational levels, aiming to discover new targets and mechanisms.
Target-based strategies revolve around a well-chosen, validated target, involving the selection of numerous ligands. These strategies rely on extensive genetic and activity data collection to find the most suitable compound for the target.
Ligand-based strategies use existing ligands that have physiological effects. They produce new, more effective or less side-effect-prone active ingredients based on structure-activity relationships.
The behavior and effect of drugs
Pharmacodynamic optimization aims to quantify the effects of drugs to select the best variant. This process involves in vitro tests, followed by in vivo animal experiments. Human trials play a crucial role in confirming the efficacy and safety of the drug during optimization.
Optimizing pharmacokinetic properties is essential for drug development. The processes of absorption, distribution, metabolism, and excretion (ADME) are thoroughly examined to ensure the drug reaches the target sites in the appropriate amounts, exerts its effect, and then leaves the body.
Toxicological studies are indispensable for ensuring the safety of drugs. In vitro and in vivo tests aim to uncover potentially toxic effects. The application of QSAR (Quantitative Structure-Activity Relationship) methods can help predict these toxic effects, thus reducing the risk in preparing for clinical trials.
The drug development process
The process of drug discovery and design marks the beginning of the complex journey of drug development. This stage aims to transition potential drugs from laboratory testing to human clinical trials and ultimately to products that can be used to treat patients.
Preclinical development
The first step in drug development is preclinical research. This involves evaluating the drug's efficacy and safety through experiments on animal models and cell cultures. These studies determine whether the drug is worth pursuing in further clinical trials.
During the pharmacodynamic studies phase, researchers investigate how the drug affects cells and isolated organs. These studies lay the groundwork for subsequent in vivo animal experiments, which examine the drug's effects and safety within more complex living systems.
Pharmacokinetic studies analyze how the body processes the drug, including absorption, distribution, metabolism, and excretion. General toxicological and safety pharmacological studies aim to ensure the molecule's safe application, assessing potential toxic effects and predicting possible side effects.
Clinical development
Following successful preclinical studies, the drug moves into the clinical development phase. This phase tests the drug's efficacy and safety in humans and consists of four main stages.
In Phase I, a small number of healthy volunteers are tested for the drug's tolerability and basic pharmacokinetic characteristics. Phase II involves testing the drug's efficacy and safety in small patient groups. In Phase III, these tests are repeated on larger patient groups to confirm the drug's effects. Finally, Phase IV, which takes place after the drug is marketed, assesses its long-term effects and safety in the general population.
Development of generic and biosimilar Drugs
Original drug patents typically last for 20 years. After they expire, there is an opportunity to develop generic and biosimilar drugs. For generic drugs, developers must prove that the new product is chemically identical to the original and produces the same plasma concentrations.
Biosimilar drugs require additional studies to demonstrate biological similarity and therapeutic equivalence. During the approval process, these drugs must also meet stringent regulatory requirements.
Quality assurance in drug development
Quality assurance is crucial at every stage of drug development. Each phase must adhere to strict quality assurance systems to ensure the reliability and authenticity of the drug and its test data. For clinical trials, the quality assurance system must guarantee the safety of participants, protect their rights, and secure their personal data.
In the European Union, the quality of preclinical studies is regulated by Good Laboratory Practice (GLP) guidelines, manufacturing by Good Manufacturing Practice (GMP), and the planning and execution of clinical trials by Good Clinical Practice (GCP) standards. These regulations ensure that every step of the drug development process meets the highest quality and ethical standards.
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