Science Buddies: "Ask an Expert"

how can I see which liquids such as soda and water help drugs such as advil dissolve better in stomach acid?

pretty please:)

Hi.

Welcome to Science Buddies! This is a great idea for a science project, and you have just enough time to get this done if you start immediately. Here is a project that is similar to your idea from the Science Buddies website, which includes two excellent projects in the background information. Use these projects for inspiration for your question, hypothesis, materials list, and experimental protocol.

https://www.sciencebuddies.org/science- ... background

Your independent variable would be the liquid that you choose to dissolve the drug, and this will make your project unique. I recommend that you use just one type of pill, and try to run your experiment in duplicate or triplicate.

Good luck. Please post again if you have any questions.

Donna Hardy

to start off thank you, but do you know I can simulate stomach acid? I found someone talk about muriatic acid but I don't know where to go from there

Hi Space Panda,

Yes, gastric acid is dilute hydrochloric (muriatic) acid with potassium and sodium chloride.

http://en.wikipedia.org/wiki/Gastric_acid

Here is a recipe for simulated gastric acid that suggests diluting 1 part muriatic acid (12 M HCl) to 60 parts of water. This will make a solution equivalent to 0.2 M HCl, which will be within the pH 1-3 range expected for gastric acid.

Gastric acid also contains about 15 mM potassium chloride, KCl. You could use salt substitute from the grocery store and add 1.1 grams of this to 1 liter of your gastric acid.

http://www.wjgnet.com/1007-9327/11/5259.pdf

http://en.wikipedia.org/wiki/Potassium_chloride

Gastric acid also contains about 4 mM sodium chloride, so you could also 0.23 grams of table salt to each liter of stomach acid.

The hydrochloric acid is the most important ingredient, so you can omit the potassium and sodium, if necessary.

Don't forget that body temperature is about 37 degrees Centigrade. Do you have any way to gently heat the samples slightly?

Donna Hardy

would it help if i left the acids in the sun for a while?

Hi Space Panda,

Leaving your samples in the sun for a while would certainly warm the samples and get them closer to body temperature. However, temperature should be one of your controlled parameters, so if you don't have an incubator or water bath that will maintain 37 degrees Centigrade, do your experiment at ambient temperature. It would be good if you could measure the temperature.

You can explain in your discussion section that you know it would have been ideal to use a higher temperature, and that you would expect results to be faster at a higher temperature, but you did not have the equipment available to maintain samples at 37 degrees C. The science fair judges will give you credit for being aware of the importance of temperature in the dissolution of the pills.


Donna Hardy