BMS 113 · Common Core (Tronc commun)Section 2.2 · Sources of drugs
Section 6 of 31
Animals, microorganisms and minerals
Distinguish animal, microbial and mineral sources of drugs, and name the main products each one supplies.
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Why this matters
If you ignore this, you may assume that animal, microbial and mineral medicines are unimportant or interchangeable. These sources still supply insulin, heparin, antibiotics, vaccines, iron and iodine, and each one brings its own quality risk. This prepares Unit 2.3, where biotechnology replaces animal tissue.
What you need to know first
You should already be able to sort a medicine by where it comes from and know that a vaccine teaches the immune system to defend itself. Unit 2.1 introduced the ideas of source, active ingredient and control of the raw material.
Words to know (4)
Antibiotic
A substance that kills other microorganisms or stops them growing, usually produced by a bacterium or a fungus. Penicillin G, obtained from a mould, is an antibiotic.
Vaccine
A preparation that shows the immune system a weakened, killed or partial pathogen so that the body learns to defend itself. The BCG vaccine protects against tuberculosis.
Anticoagulant
A medicine that slows down or prevents the clotting of blood. Heparin, obtained from the leech, is an anticoagulant.
Electrolyte
A salt or ion that the body needs in a narrow range to keep its internal environment working. Sodium chloride is given as an electrolyte after heavy fluid loss.
One idea at a timeIdea 1 / 4
In one sentence Animals supply only a small number of medicines, but those products, such as insulin, heparin and vitamin A, are important.
Very few medicines are obtained from animals
The source and use are linked: animal tissue supplies a substance the human body also needs. Vitamin A comes from liver and cod fish oil and is used in the treatment of night blindness. Insulin comes from the pancreas of pigs and cows and is used in diabetes mellitus. Absorbable sutures come from horses and are used for suturing wounds. Heparin comes from the leech and is an anticoagulant. Thyroid extract comes from the thyroid gland and is used in goitre. Estrogen comes from the urine of young mares and is used in hormone replacement therapy. Human blood is used for transfusion.
For example
A patient with diabetes may once have received insulin extracted from pig or cow pancreas; the same patient may now receive human insulin made by biotechnology instead.
Pause and check yourself
Give two medicines obtained from animals and one use for each.
Show the answer
Insulin comes from the pancreas of pigs and cows for diabetes, and heparin comes from the leech as an anticoagulant.
Read detailed explanations
Fermentation: how a microbe becomes a production plant
When a medicine comes from a microorganism, the microorganism is grown rather than harvested. A small sample of the producing strain is placed in a sterile nutrient medium in a vessel, where it multiplies and, as part of its own metabolism, releases the substance of interest into the medium. The liquid is then processed to extract and purify the medicine. This process, fermentation, is the same principle used in breweries, which is why the lecture notes mention breweries alongside antibiotics. It explains several practical features of antibiotic production. It is a biological process, so it is sensitive to temperature, oxygen, pH and contamination, and a single unwanted organism in the vessel can ruin a whole batch. It produces mixtures, so purification is a major part of the work. And it is inherently variable, so each batch must be tested before release. Understanding fermentation thus explains why microbial-source medicines need strict manufacturing control rather than simply good chemistry.
Minerals, electrolytes and the antacid example
Mineral medicines act by simple chemistry, and that simplicity is their strength. Sodium chloride is an electrolyte: the body needs sodium and chloride ions in a narrow range, and when they are lost through diarrhoea, vomiting or sweating, replacing them restores the internal environment. Iron is needed to build haemoglobin, so a deficiency causes anaemia and giving iron corrects it; iodine is needed by the thyroid gland, and its lack produces goitre. Aluminium hydroxide and magnesium trisilicate and sulfate are antacids: they react with, or neutralise, the hydrochloric acid in the stomach, which relieves the symptoms of excess acid. Fluorine in toothpaste strengthens the teeth, and calcium with phosphorus strengthens bone and teeth. Liquid paraffin and kaolin act as laxatives. Two lessons follow. First, a mineral medicine does not need a receptor or a complex mechanism to be useful. Second, because these substances are simple and cheap, they are easy to give in excess: the same chemistry that corrects a deficiency can disturb the balance when the dose is wrong, so even electrolyte replacement follows a measured plan.
Explore the diagram
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Animal, microbial and mineral sources
Three columns give the animal, microbial and mineral sources of drugs with their active ingredients and uses, and a reminder about contamination and parenteral safety.
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01 / 4Animals
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Animals
Very few medicines come from animals. Cod-liver oil and liver supply vitamin A for night blindness; the pancreas of pigs and cows supplied insulin for diabetes; horses provide absorbable sutures; the leech provides heparin, an anticoagulant; thyroid gives thyroid extract, mare urine gives estrogen, and human blood is transfused.
Schematic grouping; not to scale. One source can yield several products and several sources can yield the same molecule, so the lists follow the lecture notes and are not exhaustive.
Key points to remember
✓Animal sources are few but decisive: vitamin A, insulin, sutures, heparin, thyroid extract and estrogen.
✓Because animal tissue is biological, it can carry microbes, so these medicines need stricter sourcing and sterilisation.
✓Microorganisms supply antibiotics and vaccines, and they also drive the fermentation used in breweries.
✓Minerals supply simple but essential medicines such as iodine, iron, salt, antacids and oxygen.
Go deeper
Worked example
Classifying medicines by their source. You are given five medicines — insulin, heparin, Penicillin G, iron and the BCG vaccine — and asked to classify each as animal, microbial or mineral, state the product, and explain one quality problem attached to that kind of source.
Insulin: an animal source when taken from the pancreas of pigs and cows; the quality problem is contamination of animal tissue with pathogenic microbes, and it is used in diabetes mellitus.
Heparin: an animal source, obtained from the leech, used as an anticoagulant; being biological material it must be screened and purified before use.
Penicillin G: a microbial source, an antibiotic produced with the help of a microorganism; its production depends on a living culture and on fermentation.
Iron: a mineral source, obtained from soil and water, used in anaemia; its quality control concerns the purity and the exact content of the salt, not infection.
BCG vaccine: a microbial source, a vaccine against tuberculosis prepared from a bacterium, and a product whose identity and potency must be verified batch by batch.
Naming the source is not a botanical curiosity: it tells you the product, how it is made, and which quality risk matters most — infection for animal tissue, culture control for microorganisms, and purity for minerals.
Common misconception
Students often think that because only a few medicines come from animals, animal products are unimportant. In fact animal sources gave medicine some of its most decisive treatments — insulin, heparin, vitamin A and vaccines — and their main limitation is the risk of microbial contamination, not a lack of usefulness.
Check your reasoning
A manufacturer can obtain the same antibiotic either by growing a microorganism or by chemical synthesis. What does the choice change?
Reveal an answer
It changes the production system and therefore the quality risks. Growing a microorganism means controlling a living culture, its nutrients, its temperature and possible contamination; chemical synthesis means controlling reagents, reaction steps and purity. The finished medicine must meet the same standards either way, but the failures that threaten those standards are different.
Where this comes from
BMS 113 General Pharmacology I lecture notes · Unit 2, pp. 11–12
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About this course and its sources
Bilingual lessons organised from the supplied BMS 113 General Pharmacology I lecture notes. Diagrams are original educational schematics; pharmacology, nursing and French-language review are pending.