subject: Where do drugs come from and what is their basic componants? [print this page] Where do drugs come from and what is their basic componants?
Traditionally, drugs were derived from natural sources, such as:
plants
animals
minerals.
Today, however, laboratory researchers have used traditional knowledge, along with chemical science, to develop synthetic drug sources. One advantage of chemically developed drugs is that they're free from the impurities found in natural substances. Also, researchers and drug developers can manipulate the molecular structure of substances such as antibiotics so that a slight change in the chemical structure makes the drug effective against different organisms. The first-, second-, third-, and fourth-generation cephalosporins are an example.
Sowing the seeds of drugs
The earliest drug concoctions from plants used everything: the leaves, roots, bulb, stem, seeds, buds, and blossoms. Subsequently, harmful substances often found their way into the mixture.
Active agents
As the understanding of plants as drug sources became more sophisticated, researchers sought to isolate and intensify active components while avoiding harmful ones. The active components of plants vary in character and effect:
Alkaloids, the most active components in plants, react with acids to form a salt that's able to dissolve more readily in body fluids. The names of alkaloids and their salts usually end in "-ine"; examples include atropine, caffeine, and nicotine.
Glycosides are naturally occurring active components that are found in plants, and have both beneficial and toxic effects. They usually have names that end in "-in", such as digoxin.
Gums give products the ability to attract and hold water. Examples include seaweed extractions and seeds with starch.
Resins, of which the chief source is pine tree sap, commonly act as local irritants or as laxatives and caustic agents.
Oils, thick and sometimes greasy liquids, are classified as volatile or fixed. Examples of volatile oils, which readily evaporate, include peppermint, spearmint, and juniper. Fixed oils, which aren't easily evaporated, include castor oil and olive oil.
Aid from animals
The body fluids or glands of animals are also natural drug sources. The drugs obtained from animal sources include:
hormones, such as insulin
oils and fats (usually fixed), such as cod-liver oil
enzymes, which are produced by living cells and act as catalysts, such as pancreatin and pepsin
vaccines, which include suspensions of killed, modified, or attenuated microorganisms, or antigenic materials obtained from these.
Many minerals
Metallic and nonmetallic minerals provide various inorganic materials not available from plants or animals. Mineral sources are used as they occur in nature or can be combined with other ingredients. Examples of drugs that contain minerals are iron, iodine, and magnesium salts.
In the lab
Today, most drugs are produced in laboratories. Examples of such drugs include thyroid hormone (from natural sources) and cimetidine (from synthetic sources).
DNA paving the way
Recombinant deoxyribonucleic acid (DNA) research has led to another chemical source of organic compounds. For example, the manipulation and reordering of genetic information enables scientists to develop bacteria that produce insulin for humans.
