New classes of pharmaceuticals

In the latter part of the 19th century a number of important new classes of pharmaceuticals were developed. In 1869 chloral hydrate became the first synthetic sedative-hypnotic (sleep-producing) drug. In 1879 it was discovered that organic nitrates such as nitroglycerin could relax blood vessels, eventually leading to the use of these organic nitrates in the treatment of heart problems. In 1875 several salts of salicylic acid were developed for their antipyretic (fever-reducing) action. Salicylate-like preparations in the form of willow bark extracts (which contain salicin) had been in use for at least 100 years prior to the identification and synthesis of the purified compounds. In 1879 the artificial sweetener saccharin was introduced. In 1886 acetanilide, the first analgesic-antipyretic drug (relieving pain and fever), was introduced, but later, in 1887, it was replaced by the less toxic phenacetin. In 1899 aspirin (acetylsalicylic acid) became the most effective and popular anti-inflammatory, analgesic-antipyretic drug for at least the next 60 years. Cocaine, derived from the coca leaf, was the only known local anesthetic until about 1900, when the synthetic compound benzocaine was introduced. Benzocaine was the first of many local anesthetics with similar chemical structures and led to the synthesis and introduction of a variety of compounds with more efficacy and less toxicity.

Transitions in drug discovery

In the late 19th and early 20th centuries, a number of social, cultural, and technical changes of importance to pharmaceutical discovery, development, and manufacturing were taking place. One of the most important changes occurred when universities began to encourage their faculties to form a more coherent understanding of existing information. Some chemists developed new and improved ways to separate chemicals from minerals, plants, and animals, while others developed ways to synthesize novel compounds. Biologists did research to improve understanding of the processes fundamental to life in species of microbes, plants, and animals. Developments in science were happening at a greatly accelerated rate, and the way in which pharmacists and physicians were educated changed. Prior to this transformation the primary means of educating physicians and pharmacists had been through apprenticeships. While apprenticeship teaching remained important to the education process (in the form of clerkships, internships, and residencies), pharmacy and medical schools began to create science departments and hire faculty to teach students the new information in basic biology and chemistry. New faculty were expected to carry out research or scholarship of their own. With the rapid advances in chemical separations and synthesis, single pharmacists did not have the skills and resources to make the newer, chemically pure drugs. Instead, large chemical and pharmaceutical companies began to appear and employed university-trained scientists equipped with knowledge of the latest technologies and information in their fields.

As the 20th century progressed, the benefits of medical, chemical, and biological research began to be appreciated by the general public and by politicians, prompting governments to develop mechanisms to provide support for university research. In the United States, for instance, the National Institutes of Health, the National Science Foundation, the Department of Agriculture, and many other agencies undertook their own research or supported research and discovery at universities that could then be used for pharmaceutical development. Nonprofit organizations were also developed to support research, including the Australian Heart Foundation, the American Heart Association, the Heart and Stroke Foundation of Canada, and H.E.A.R.T UK. The symbiotic relationship between large public institutions carrying out fundamental research and private companies making use of the new knowledge to develop and produce new pharmaceutical products has contributed greatly to the advancement of medicine.


Establishing the fight against infectious disease

Early efforts in the development of anti-infective drugs

For much of history, infectious diseases were the leading cause of death in most of the world. The widespread use of vaccines and implementation of public health measures, such as building reliable sewer systems and chlorinating water to assure safe supplies for drinking, were of great benefit in decreasing the impact of infectious diseases in the industrialized world. However, even with these measures, pharmaceutical treatments for infectious diseases were needed. The first of these was arsphenamine, which was developed in 1910 by the German medical scientist Paul Ehrlich for the treatment of syphilis. Arsphenamine was the 606th chemical studied by Ehrlich in his quest for an antisyphilitic drug. Its efficacy was first demonstrated in mice with syphilis and then in humans. Arsphenamine was marketed with the trade name of Salvarsan and was used to treat syphilis until the 1940s, when it was replaced by penicillin. Ehrlich referred to his invention as chemotherapy, which is the use of a specific chemical to combat a specific infectious organism. Arsphenamine was important not only because it was the first synthetic compound to kill a specific invading microorganism but also because of the approach Ehrlich used to find it. In essence, he synthesized a large number of compounds and screened each one to find a chemical that would be effective. Screening for efficacy became one of the most important means used by the pharmaceutical industry to develop new drugs.

The next great advance in the development of drugs for treatment of infections came in the 1930s, when it was shown that certain azo dyes, which contained sulfonamide groups, were effective in treating streptococcal infections in mice. One of the dyes, known as Prontosil, was later found to be metabolized in the patient to sulfanilamide, which was the active antibacterial molecule. In 1933 Prontosil was given to the first patient, an infant with a systemic staphylococcal infection. The infant underwent a dramatic cure. In subsequent years many derivatives of sulfonamides, or sulfa drugs, were synthesized and tested for antibacterial and other activities.