Development of drugs process

To conduct clinical research that meets the requirements of the FDA for new product approval, it is essential to understand these regulations and their subsequent impact on the clinical development process of drugs, devices, and biologies. 

The safety of chemicals, like drugs for human use, relies on testing and evaluation in other animal species such as rats and mice. Therefore the differences between species in this context have to be recognized. For example, the disposition of a particular chemical in a rat or mouse may be different and so studies in such species do not always show how poisonous it will be in humans. The drug may be more or less poisonous to a rodent than to a human. For this reason human volunteers are exposed early on in the development process of drugs and human tissues are used in vitro. Knowledge of the disposition of the drug in humans reveals whether the species initially used (for example, rats) are appropriate. If not, other species wiU be studied and used for the safety evaluation. These points will be discussed in more detail in Chapter 12. 

To speed the process of drug discovery, combinatorial chemistry> has been developed to prepare what are called combinatorial libraries, in which anywhere from a few dozen to several hundred thousand substances are prepared simultaneously. Among the early successes of combinatorial chemistry is the development of a benzodiazepine library, a class of aromatic compounds much used as antianxiety agents. 

Combinatorial chemistry, a new chapter of organic synthesis, is now developing rapidly. This new approach to synthesizing large designed or random chemical libraries through application of solid phase synthetic methods, promises to revolutionize the process of drug discovery in the pharmaceutical industry.24... 

One leading industrial scientist said about the process of drug development 108... 

For PK assays, it is generally believed that most matrix effects are due to the sample matrix (typically plasma). While this is correct in many cases, this assumption has some exceptions (vide infra). One of the most useful tools for avoiding matrix effects is studying the sample matrix and proposed assay by using the post-column infusion technique described by Bonfiglio et al.14S This technique allows visualization of the portion of the chromatographic step affected by ion suppression.161721 Xu et al.101 recommended inclusion of this step in the method development process for drug discovery PK assays. 

Many literature sources describing formulation and manufacture of different pharmaceutical dosage forms are available.10,11 The primary objective of this chapter is to describe an integrated process of drug development, demonstrating how all activities from lead selection to LCM are interrelated. Various scientific principles underlying these activities are described. 

Today, personnel from a myriad of fields are involved in the process of drug discovery and development, from scientists, clinicians, and medical practitioners to statisticians. Even persons from seemingly disparate occupations, such... 

The business model of the innovative pharmaceutical industry is to transform the results of basic medical research into products that provide health benefits to the patient. This model is characterized by a high risk of failure in the development of new products, coupled with the benefit of market exclusivity for a number of years if a product can be successfully developed and is approved by the regulatory agencies. Only very few chemical entities complete the development process from drug discovery to a commercial product. But those products that do reach the marketplace have to yield sufficient financial rewards to assure that the... 

Since then, the process of drug development and discovery has become increasingly complex. A new technology appeared, termed biotechnology, which placed this process on a more scientific basis. A new set of firms appeared smaller and interposed between the scientific community and the major pharmaceutical firms. It is reported that between 25% and 40% of sales by the major pharmaceutical companies currently are from products that originated in the biotech sector. 

With just a few relatively simple techniques it is possible to get all the important information needed to devise appropriate dosing schedules. We will only look at the simplest of these, which are of everyday, practical importance in clinical practice. All of these, and several others, are carried out in the process of drug development, and their results must be reported to regulatory authorities before a new drug may be registered for use. 

---