Which Type of Pain Reliever Dissolves Faster: 
Trade or Generic?

Researched by Chris C.


The purpose of this experiment was to determine the dissolution times of three types of pain relievers and compare the dissolution times of their trade and generic form.

I became interested in this idea because so many commercials of brand name pain reliever's claim theirs is the best.

The information gained from this experiment will help people make better choices on which pain reliever works best for them.


My first hypothesis is that in the same type of pain reliever, there will be no difference in the dissolution times between the generic and brand name.

I base my hypothesis on the web site called "I'll buy that! Consumer Education Series" saying, "Generic drugs are chemically equivalent to brand name drugs, but costs a lot less."

My second hypothesis is that there will be a difference in the dissolution times among the different types of pain relievers. 

I base my second hypothesis on my background research from three Internet sites called RxList Acetaminophen; RxList Aspirin; and RxList Ibuprofen, which stated their chemical ingredients.  Since the chemical ingredients are different, the dissolution times will be too.

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The constants in this study were:

  • The temperature of water (36-37°C)
  • The temperature of hydrochloric acid (36-37°C)
  • Amount of water (125mL)
  • Amount of hydrochloric acid (100mL)
  • Where the experiment was conducted
  • Strength of pain reliever (regular)
  • pH of hydrochloric acid (pH 3)

The manipulated variable was the pain reliever I used in hydrochloric acid and water.

The responding variable was the amount of time it took for each pain reliever to dissolve.

To measure the responding variable I would time the dissolving pain reliever in seconds using a digital timer.

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20 tablets of acetaminophen
20 tablets of ibuprofen
20 tablets of aspirin
20 tablets of Tylenol
20 tablets of Advil
20 tablets of Bayer 
5L hydrochloric acid (HCl)
3 beakers
2 digital timers
2 magnetic stirrers
1 Celsius thermometer
1 microwave
1 pair of latex gloves
1 roll of paper towels
1 pair of goggles
1 apron
-- tap water

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  1. Obtain 5L of HCl solution with a pH of 3
  2. Get one big beaker and pour 400mL in it.  Every time you run out, fill it with more, as you need it
  3. The temperature of the HCl should be 36-37 degrees C
  4. Get two small beakers and pour 100mL of acid in each
  5. Put the beakers on the stirrer
  6. Drop one magnet in each beaker
  7. Set the magnetic stirrer speed to about the middle
  8. Drop one tablet in one beaker
  9. Once you drop one tablet, start the first timer.
  10. When you drop the second tablet, start the other timer.
  11. When the tablet is completely dissolved, turn of the timer and the stirrer off, then record the time
  12. Empty out the HCl, and wash all of the supplies in water.
  13. Now dry the materials used by wiping them with a paper towel.
  14. Repeat steps 2-13 five times for each type of pain reliever.
  15. Using the next type of pain reliever, repeat steps 2-14.
  16. Now repeat steps 1-15, except using tap water instead of HCl.  Also use 125mL of water instead of 100.
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The original purpose of this experiment was to determine the dissolution times of three types of pain relievers and compare the dissolution times of their trade and generic form.

The results of the experiment showed the trade form of the pain relievers dissolved faster than the generic form except for aspirin.  Generic aspirin dissolved faster then the trade name, Bayer.

See the Table and Graphs

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My first hypothesis was that in the same type of pain relievers, there would be no difference in the dissolution times between the generic and brand name.

The results indicate that this hypothesis should be rejected because the dissolution times were somewhat different.

My second hypothesis was that there would be a difference in the dissolution times among the different types of pain relievers.

The results indicate that this hypothesis should be accepted because the dissolution times were different among the different types of pain relievers.

If I were to conduct this experiment again, I would include water, hydrochloric acid and temperature in my manipulated variables. For water and hydrochloric acid, I would use different amounts and different temperatures.  Also, with hydrochloric acid, I would experiment with different pH levels. These factors will probably result in significant differences in dissolution times among the different types of pain relievers. 

To make my experiment more accurate, I would make sure that the speed of the magnetic stirrer would be the same and in the same spot for both beakers. The size of the magnet should be the same.  In the case of my experiment, the magnets differed in size. I suspect the bigger magnet could probably make the dissolution times faster. Temperature of both water and hydrochloric acid needs to be controlled as this may also affect the dissolution times. 

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Human health is very important to our happiness and survival.  Medicine can be used for humans when they are sick or have a disease. Pain relievers often come in tablets and they help deal with pain and help us feel better.  Medicine that dissolves faster takes effect faster.


Pain Relievers

A pain reliever is a drug that relieves pain.  Some classes of pain relievers are acetaminophen, ibuprofen, and aspirin.  They all relieve minor pain and reduce fevers.  They also are non-prescription and safe to take for almost all people.  However, they can affect people in different ways. 


Acetaminophen is the safest pain reliever for kids.  It does not cause stomachaches and it is a good medicine to relieve pains and aches and reduce fevers.  Acetaminophen is safe to take but if taken in large doses, it can cause liver damage. One trade name of acetaminophen is Tylenol.


Aside from being a pain reliever, ibuprofen also reduces inflammation and thins blood.  It does not have many side affects, however, it has not been shown that it is the best for children. Common side effects are stomach bleeding, nausea and can make existing kidney problems.  One trade name of ibuprofen is Advil.


Aspirin is the most commonly used drug in America because it is cheap and it can be used to treat many illnesses.  It thins the blood and reduces inflammation so it is good for arthritis.  Aspirin is known to reduce the risk of a heart attack or stroke.  Some people take aspirin daily to prevent blood clots.  Even though aspirin has many positive effects, it also has some negative side effects.  For example, it causes stomach bleeding like ibuprofen and it makes ulcers and gout worse.  Children SHOULD NOT take this pain reliever to relieve viral diseases like chicken pox or the flu.  If children do take it with these diseases, it may cause a brain disease called Reye’s Syndrome.  Reye’s Syndrome could be fatal.  Overall, taking aspirin has more advantages than disadvantages.  One trade name of aspirin is Bayer.



The American Heritage Student Dictionary refers to acid as "Any of a class of substances that when dissolved in water are capable of reacting with a base to form salts and release hydrogen ions."  The acid used in this experiment was hydrochloric acid.  Hydrochloric acid is a clear liquid that is very corrosive.  It has a very strong odor and it can cause severe burns.  The pH of a liquid is the acidity level of that liquid.  For example, the pH of pure hydrochloric acid is 0.  The lower the pH the more dangerous.  Below is a table of pH levels:

Pure Hydrochloric Acid
Stomach acid
Lemon Juice
Rainwater (unpolluted)
Pure Water
Egg Whites
Baking Soda



Water is a clear, colorless liquid that has no taste or smell.  When you mix something with water, it could have a chemical reaction.  A solution is a mix of 2 or more substances that cannot be separated by filters.  A liquid that can dissolve another liquid is a solute, and a liquid that only mixes is a solvent.  If you have two solutions that can mix, they are miscible. A solid that can dissolve in a liquid is soluble.  The chemical abbreviation for water is H20.


Disease- an illness mentally or physically 
Dissolution- the process of breaking into parts
Gout- disease which hard residue of salt and urine form in joints
Hydrochloric acid- made of hydrogen and chlorine. Chemical abbreviation is HCl
Inflamed- swollen
Miscible- able to mix
Reye’s syndrome- an uncommon brain disease that can be lethal
Soluble- able to dissolve
Solute- Capable of dissolving another substance 
Solvent- Capable of mixing another substance 
Ulcer- Inflamed, pus filled or mucous membrane on body


When people get sick it is usually treated with some type of medicine. More common types of illnesses include flu, colds, headache, inflammation of some parts of the body, etc.  Pain relievers are common drugs used to treat these types of illness. 

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  • "Acetaminophen." [Online] Available http://www.rxlist.com/cgi/generic/apap.htm
  • "Acids, Bases and pH." [Online] Available http://web.jjay.cuny.edu/~acarpi/NSC/7-ph.htm
  • "Are Aspirin, Acetaminophen, and Ibuprofen different?" [Online]  Available http://www.chime.ucl.ac.uk/student
  • "Aspirin vs. Acetaminophen vs. Ibuprofen." [Online] Available http://www.yourhealth.com/ahl/2001.html
  • Clayman, Charles. The Human Body, London: Dorling Kindersley, 1995. Pp. 154
  • "Dissolve; Dissolution; Aspirin; Hydrochloric Acid; Miscible; Soluble," The American Heritage Student Dictionary, 1994. Pp. 59, 298, 489, 627, 900
  • Fox, Mary Ann.  "Solution," World Book Encyclopedia, 1998. Vol. 18
  • Johnson, Eugene.  "Acetaminophen," World Book Encyclopedia, 1999. Vol. 1
  • Johnson, Eugene.  "Ibuprofen," World Book Encyclopedia, 1999. Vol. 10
  • Liebeskind, Herbert.  "Hydrochloric acid," Encyclopedia Americana, 1999. Vol. 14
  • "Material Safety Data Sheet." [Online] Available http://intranet.michener.on.ca/msds/hchem/hclt.htm
  • "Simple Chemistry." [Online] Available http://www.tsba.org/~judith/simplechem.html 
  • Sladek, N. E.  "Aspirin," World Book Encyclopedia, 1999. Vol. 1
  • Smith, Carolyn.  "Hydrochloric acid," World Book Encyclopedia, 1995. Vol. 9
  • "The "one-cent" Wonder Drug." [Online] Available http://www.yourhealth.com/bin/build_result_doc.pl?searchterm=asprin/980945.htm
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I would like to thank the following people for their help with my science project:

  • First I would like to thank my Dad and my Mom who took me to general stores and buying the materials.  If they didn’t do that for me, I wouldn’t have been able to do my experiment.
  • Next, I would like to thank Mr. Gunner for staying after school to let his kids finish their project journal.  He also let me use paper and other materials.
  • I would like to thank all my friends that helped or supported me during this project.
  • Also, I would like to thank Ms. Gustin for lending me some hydrochloric acid.  If I didn’t have the hydrochloric acid, my project would be impossible.
  • Finally I would like to thank Mr. Newkirk and Mrs. Pasckvale for staying after school and giving me good advice for my project.  Mr. Newkirk helped me set up my experiment and Mrs. Pasckvale gave me tips on cutting the items out for the display.


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