Have you ever asked yourself why medicine comes in so many different forms?
Pills, liquids, creams, and injections – all of these are forms of medicines used to cure,
halt, treat, or prevent diseases.
Why do so many different forms exist? How are they different from each other?
One of the things that makes each form different is its mechanism of drug delivery. Each form
delivers the drug's active ingredients into the body in a different way. For example,
Topical drugs such as creams or ointments are usually applied to the skin,
or another surface of the body, and the active ingredients are absorbed through the skin.
Oral drugs are taken by mouth and travel through the digestive system
where they dissolve and get absorbed into the bloodstream.
Injections or shots are delivered into a person's body using a needle and a syringe,
which allows for rapid absorption of the active ingredients into the bloodstream.
Why does it matter how a medicine gets into the body?
It matters because every drug is different! Each active ingredient
in a drug has different chemical and physical properties. Each one functions in a different
way and has to be delivered to the right location inside the body to be effective.
As an example, let's look at one specific medication that you may have heard of: Insulin.
Insulin is a protein. Like other proteins it is made from a chain
of amino acids and folded into a complex three-dimensional structure.
In most people insulin is produced by the pancreas to help balance blood glucose levels. In patients
with diabetes, the body may not respond to insulin properly, may not produce enough insulin,
or may stop producing insulin all together. This is why many people with diabetes need
insulin as medication to manage their blood glucose levels.
Many people with diabetes have to give themselves multiple shots of insulin
every day. Wouldn't it be nice if they could just swallow an insulin pill instead?
Like injections, oral drugs eventually make their way
into the bloodstream. So, why isn't there an insulin pill?
To answer this question, let's do an experiment!
The experiment uses a model of insulin to investigate what happens to insulin
if it is taken orally versus as an injection.
This is how our insulin model works:
The correct shape and three-dimensional structure of insulin is important for its function. If its
structure is disrupted, the insulin will become ineffective. In your experiment,
you will create three-dimensional jello shapes to represent the insulin medication.
The jello pieces, or the insulin they represent, are then treated in two different ways.
The first jello treatment simulates what would happen to the insulin if it was taken orally
and encountered the digestive system, specifically the stomach.
A protease solution will mimic the gastric environment in the stomach.
Water represents the stomach fluids, and meat tenderizer represents the proteases present
in the stomach. In our stomachs, proteases help break down the proteins in the food that we eat.
The second jello treatment simulates what happens to the insulin when it is injected into the body,
where it gets absorbed directly into the bloodstream.
In this simulation, a red-colored water solution represents the blood in our bloodstream.
Now that you know how the model works, you can start doing the experiment!
These are the materials you will need. Once you have all your materials ready,
start by making the jello shapes.
Grease the insides of the baking pans or
plastic containers with a paper towel and a few drops of oil.
Pour 250 milliliters of water into the measuring cup and add a few drops of food
coloring. Be sure to use a color other than red. Dissolve 35 grams of unflavored gelatin powder
in the colored water. Stir well and let it rest for one minute.
While waiting, heat three cups of water until boiling.
Add the hot water to the dissolved jello and stir until all the gelatin is dissolved.
Pour the hot liquid evenly into the pans. The jello should be about 1
to 1.5 centimeters high in both pans. Then chill the jello until it is firm.
When the jello is firm, prepare your jello, or insulin shapes.
Transfer both jello molds to a cutting board using a spatula.
Then use the cookie cutter to cut 20 shapes out of the jello. These
shapes will represent the insulin. Don't forget to take pictures of
them and make notes of their appearance before continuing with the experiment.
Next, prepare the red-colored water that represents the blood.
Add a few drops of red food coloring to a container of water.
Then prepare the protease solution, which represents the gastric environment.
Pour 1 cup (or 100 grams) of meat tenderizer into the second container.
Add one cup of water and stir well. If some of the meat tenderizer doesn't dissolve, that is okay.
Now you should have all the main components of your model ready to go.
Remember, the jello shapes model insulin, the red-colored water models the blood in
the bloodstream, which insulin enters rapidly when injected,
and the protease solution models the gastric environment in the
stomach that insulin in a pill form would encounter before entering the blood stream.
This means it is time for the actual experiment!
Make sure to label your treatment conditions first before you start your jello treatments.
Then carefully place 10 jello shapes in the container with the red-colored water.
Make sure all the jello shapes are in the water and are not lying on top of each other.
This test models insulin being injected into the body and absorbed into the bloodstream.
Place the remaining 10 jello shapes in the container with the protease solution.
Again, make sure all jello shapes are in the solution and are not lying on top of each other.
This test models insulin being ingested and passing through the digestive system.
Let the jello shapes sit in the two solutions for two hours.
Then use a spoon to carefully take the jello shapes out of the solutions,
one by one. Look at the jello shapes and carefully touch them to see and feel how they have changed.
You can also put the shapes back into the original cookie cutter to measure their sizes.
Don't forget to take pictures of the jello shapes and write down your observations.
When assessing the jello shapes, keep in mind that they represent the peptide hormone insulin.
If the jello shape or three-dimensional structure has been compromised in any way, this
means that the insulin has become ineffective! Compare how many jello pieces kept their shape
in both testing scenarios. Use your data to visualize your results in a bar graph.
Looking at your results, you should be able to answer the following questions:
Can you tell from your data, what happens to insulin in a
gastric environment versus the bloodstream? What do your results suggest about how easy
or hard it is to make an effective insulin pill? And finally, can you now explain why there are
different forms of medicines and not all of them are pills?