Ciencias.com.es

MEDICINE MANUFACTURING
In the past, all medicines came from plants or animals. Although some important medicines still come from plants or animals (e.g. morphine), most medicines used today in the developed world are manufactured through chemical processes.
All new medicines must undergo thorough testing before being approved for use. Before a new medicine can be tried in humans it must undergo extensive testing in the laboratory, to assess its safety and biological activity. This 'pre-clinical' development stage may last as long as 3 or 4 years. Then clinical trials in human volunteers, determine if a medicine is safe and effective, at what doses it works best and what side effects it causes.
A typical clinical trial development programme: a) Phase I * 20-100 healthy volunteers up to 1 year.
* To ensure the medicine is safe and find the most suitable dose. b) Phase II * Up to several hundred patients, 1-2 years* To assess effectiveness and look for side effects.
c) Phase III * Several hundred to several thousand patients, 2-4 years.
* To confirm effectiveness and monitor any side effects from long-term use. Only one or two of thousands of new chemical compounds evaluated ever gets as far as being approved for use on prescription by doctors. It costs in the region of US$800 million to develop a new medicine and can take 12 years to make a new medicine available for doctors to prescribe.
Each new medicine entering development is given a chemical name (e.g. lisinopril, used to treat high blood pressure ). Occasionally, this chemical name is called something different in different countries (eg. paracetamol and acetaminophen are the same). However, once a medicine has been licensed for use in patients by the medicines agency of a country, the manufacturer can sell the medicine under a brand or trade name (eg Zestril).
Patenting of a new medicine guarantees the manufacturer a 20-year period of protection, during which no other companies can legally make or sell the medicine. However, once this period has expired, other pharmaceutical companies can make the medicine. These 'copycat' medicines are called 'generic' medicines.
The pharmaceutical and medicine manufacturing industry develops and produces a variety of medicinal and other health-related products that save the lives of millions of people from various diseases and permits many people suffering from illness to recover to lead productive lives.
Thousands of medications are available today for diagnostic, preventive, and therapeutic uses. In addition to aiding in the treatment of infectious diseases such as pneumonia, tuberculosis, malaria, influenza, and sexually transmitted diseases, these medicines also help prevent and treat cardiovascular disease, asthma, diabetes, hepatitis, cystic fibrosis, and cancer. Discoveries in veterinary drugs have controlled various diseases, some of which are transmissible to humans.
The U.S. pharmaceutical industry has achieved worldwide prominence through research and development (R&D) on new drugs, and spends a relatively high proportion of its revenue on R&D compared with other industries. Each year, pharmaceutical industry testing involves millions of compounds, yet may eventually yield fewer than 100 new prescription medicines.
For the majority of firms in this industry, the actual manufacture of drugs is the last stage in a lengthy process that begins with scientific research to discover new products and to improve or modify existing ones. The R&D departments in pharmaceutical and medicine manufacturing firms start this process by seeking and rapidly testing libraries of thousands to millions of new chemical compounds with the potential to prevent, combat, or alleviate symptoms of diseases or other health problems. Scientists use sophisticated techniques, including computer simulation, combinatorial chemistry, and high-throughput screening (HTS), to hasten and simplify the discovery of potentially useful new compounds. Most firms devote a substantial portion of their R&D budgets to applied research, using scientific knowledge to develop a drug targeted to a specific use. If the discovery phase yields promising compounds, technical teams then attempt to develop a safe and effective product based on the discoveries.
To test new products in development, a research method called "screening" is used. To screen an antibiotic, for example, a sample is first placed in a bacterial culture. If the antibiotic is effective, it is next tested on infected laboratory animals. Laboratory animals also are used to study the safety and efficacy of the new drug. A new drug is selected for testing on humans only if it either promises to have therapeutic advantages over drugs already in use or is safer. After laboratory screening, firms conduct clinical investigations, or "trials," of the drug on human patients. Human clinical trials normally take place in three phases. First, medical scientists administer the drug to a small group of healthy volunteers to determine and adjust dosage levels, and monitor for side effects. If a drug appears useful and safe, additional tests are conducted in two more phases, each phase using a successively larger group of volunteers or carefully selected patients. The final round of testing often involves a very large panel, sometimes upwards of 10,000 individuals.
After a drug successfully passes animal and clinical tests, the U.S. Food and Drug Administration's (FDA) Center for Drug Evaluation and Research (CDER) must review the drug's performance on human patients before approving the substance for commercial use. The entire process, from the first discovery of a promising new compound to FDA approval, can take over a decade and cost hundreds of millions of dollars. After FDA approval, problems of production methods and costs must be worked out before manufacturing begins. If the original laboratory process of preparing and compounding the ingredients is complex and too expensive, pharmacists, chemists, chemical engineers, packaging engineers, and production specialists are assigned to develop a manufacturing process economically adaptable to mass production. After the drug is marketed, new production methods may be developed to incorporate new technology or to transfer the manufacturing operation to a new production site.

Source: http://ciencias.com.es/images/textos/medicines.pdf