Sources Of Drugs

Where do medications come from? Historically, drugs were mainly derived from plants (eg, morphine), animals (eg, insulin), and minerals (eg, iron). Now, most drugs are synthetic chemical compounds manufactured in laboratories. Chemists, for example, can often create a useful new drug by altering the chemical structure of an existing drug (eg, adding, deleting, or altering a side-chain). Such techniques and other technologic advances have enabled the production of new drugs as well as synthetic versions of many drugs originally derived from plants and animals. Synthetic drugs are more standardized in their chemical characteristics, more consistent in their effects, and less likely to produce allergic reactions. Semisynthetic drugs (eg, many antibiotics) are naturally occurring substances that have been chemically modified.


Biotechnology is also an important source of drugs. This process involves manipulating deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) and recombining genes into hybrid molecules that can be inserted into living organisms (Escherichia coli bacteria are often used) and repeatedly reproduced. Each hybrid molecule produces a genetically identical molecule, called a clone. Cloning makes it possible to identify the DNA sequence in a gene and produce the protein product encoded by a gene, including insulin and several other body proteins. Cloning also allows production of adequate amounts of the drug for therapeutic or research purposes.