Where drugs come from
Traditionally, drugs were derived from natural sources, such as:
Today, however, laboratory researchers use traditional knowl-edge, 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.
In addition, 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.
The earliest drug concoctions from plants used everything: the leaves, roots, bulb, stem, seeds, buds, and blossoms. Subsequent-ly, harmful substances often found their way into the mixture.
As the understanding of plants as drug sources became more sophisticated, researchers sought to isolate and intensify activecomponents while avoiding harmful ones.
The active components consist of several types and vary in char-acter and effect:
· Alkaloids, the most active component in plants, react with acids to form a salt that can dissolve more readily in body fluids. The names of alkaloids and their salts usually end in “-ine.” Examples include atropine, caffeine, and nicotineGlycosides are also active components found in plants. Namesof glycosides usually end in “-in” such as digoxin. Gums constitute another group of active components. Gumsgive products the ability to attract and hold water. Examples in-clude seaweed extractions and seeds with starch.
· Resins, of which the chief source is pine tree sap, commonlyact as local irritants or as laxatives.
· Oils, thick and sometimes greasy liquids, are classified asvolatile or fixed. Examples of volatile oils, which readily evapo-rate, include peppermint, spearmint, and juniper. Fixed oils, which aren’t easily evaporated, include castor oil and olive oil.
The body fluids or glands of animals can also be drug sources. The drugs obtained from animal sources include:
· hormonessuch as insulin
· oilsand fats (usually fixed) such as cod-liver oil
· enzymes, which are produced by living cells and act as cata-lysts, such as pancreatin and pepsin
· vaccines, which are suspensions of killed, modified, or attenuat-ed microorganisms. (See Old McDonald had a pharm)
Metallic and nonmetallic minerals provide various inorganic mate-rials not available from plants or animals. The mineral sources are used as they occur in nature or are combined with other ingredi-ents. Examples of drugs that contain minerals are iron, iodine, and Epsom salts.
Today, most drugs are produced in laboratories and can be:
natural (from animal, plant, or mineral sources) synthetic.
Examples of drugs produced in the laboratory include thyroid hormone (natural) and ranitidine (synthetic).
Recombinant deoxyribonucleic acid research has led to other chemical sources of organic compounds. For example, the re-ordering of genetic information has enabled scientists to develop bacteria that produce insulin for humans.