DEVELOPMENT IN PHARMACOLOGY

Beginning in the 20th century, the fresh wind of synthetic chemistry began to revolutionize the pharmaceutical industry, and with it the science of pharmacology. New synthetic drugs, such as barbiturates and local anesthetics, began to appear, and the era of antimicrobial chemotherapy began with the discovery by Paul Ehrlich in 1909 of arsenical compounds for treating syphilis. Further breakthroughs came when the sulfonamides, the first antibacterial drugs, were discovered by Gerhard Domagk in 1935, and with the development of penicillin by Chain and Florey during the Second World War, based on the earlier work of Fleming. Many hormones, neurotransmitters and inflammatory mediators were discovered, and the realization that chemical communication plays a central role in almost every regulatory mechanism that our bodies possess immediately established a large area of common ground between physiology and pharmacology, for interactions between chemical substances and living systems were exactly what pharmacologists had been preoccupied with from the outset. The concept of 'receptors' for chemical mediators, first proposed by Langley in 1905, was quickly taken up by pharmacologists such as Clark, Gaddum, Schild and others and is a constant theme in present day. The receptor concept, and the technologies developed from it, have had a massive impact on drug discovery and therapeutics. Biochemistry also emerged as a distinct science early in the 20th century, and the discovery of enzymes and the delineation of biochemical pathways provided yet another framework for understanding drug effects. Since the 1980s, biotechnology has emerged as a major source of new therapeutic agents in the form of antibodies, enzymes and various regulatory proteins, including hormones, growth factors and cytokines. Although such products (known as biopharmaceuticals) are generally produced by genetic engineering rather than by synthetic chemistry, the pharmacological principles are essentially the same as for conventional drugs. Looking further ahead, gene- and cell- based therapies although still in their infancy, will take therapeutics into a new domain.The principles governing the design, delivery and control of functioning artificial genes introduced into cells, or of engineered cells introduced into the body, are very different from those of drug-based therapeutics and will require a different conceptual framework, which texts such as this will increasingly need to embrace if they are to stay abreast of modern medical treatment. As with other biomedical disciplines, the boundaries of pharmacology are not sharply defined, nor are they constant. Figure shows the structure of pharmacology as it appears today.