A pharmaceutical drug are used to diagnose, cure, treat, or prevent disease.

There are two main sources of drugs, plants and microorganisms.

There are a lot of drugs that use plant resources. For example:

  1. Digitalis’ leaves are used in the drug Digoxin to treat congestive heart failure (CHF).
  2. Cinchona’s bark is used in the drug Quinine to treat Malaria.
  3. Opium’s fruits are used in the drug Morphine to treat Analgesic.
  4. Eserin’s seeds are used in the drug Anticholinestrase to treat Myasthenia gravis (MG)

There are a lot of drugs that use microorganisms resources. For example:

  1. The drug Penicillin is made from penicilium notatum.
  2. The drug Chloramphenicol is made from Streptomyces Venezuelace.
  3. The drug Griseofluvin in made from Penicillin grisofullivum.
  4. The drug Streptomyum is made from Streptomyces griseus.
  5. The drug Neomycin is made from Streptomyces fradiae.

Drugs are not just developed and then used. All drugs have to be tested to make sure that they work, and are safe, before they can be prescribed. Furthermore, all drugs have to pass 3 tests:

  1. The drugs are tested using human cells grown in the laboratory.
  2. Drugs are then tested on animals. That is done by giving a drug to the animals, then monitoring them carefully for any side-effects.
  3. Clinical trials. They are tested on healthy volunteers to check they are safe. Very low doses of the drug are given to begin with. If there are no problems, further clinical trials are done to find the optimum dose for the drug.

The first test is always done on human cells grown in the laboratory to test their if the drug kills any cells or causes the cell to stop functioning properly and if the drug does what it is supposed to do. This is not done on animals (mostly mice because of the similarity of DNA between humans and mice) because of the strict laws of tests in animals in the UK. If the drug passes the test, it is then considered safe for animals use. The drug is now guaranteed to be doing what it is supposed to be doing and it needs to be tested for side effects. If there are no risky side effects the drug is tested on healthy human beings to see the effects of the drug in the human body and if it is safe or not for human use. If it passes all of those tests, clinical trial are carried to find the optimum dose of the drug. After that the drug is submitted to the NDA. When the NDA approves the drug, the drug starts getting marketed.

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The three phases of clinical trials are:

  1. Phase I trials, usually in healthy volunteers, determine safety and dosing.
  2. Phase II trials are used to get an initial reading of efficacy and further explore safety in small numbers of patients having the disease targeted by the NCE.
  3. Phase III trials are large, pivotal trials to determine safety and efficacy in sufficiently large numbers of patients with the targeted disease. If safety and efficacy are adequately proved, clinical testing may stop at this step and the NCE advances to the new drug application (NDA) stage.