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Chemistry Behind Advil
Episode 2217th June 2021 • Chemistry Connections • Hopewell Valley Student Publication Network
00:00:00 00:09:19

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Chemistry Connections

Episode #22  

Welcome to Chemistry Connections, my name is Sofie Ragins and I’m here with Xavier Jimenez and we are your host for episode #22 called The Chemistry behind Advil Today we will be discussing the chemical process that occurs when consuming advil to relieve pain  

Segment 1: Introduction to Advil

Advil temporarily relieves headaches, backaches, common colds, muscle aches, and other pain. Basically, Advil is a safe non-prescription pain reliever. This means that you or I can walk into a drug store and purchase Advil without a doctor's prescription

In 2018 nearly 24 million people purchased advil. 

The one and only active ingredient that is what actually causes the pain relief, Ibuprofen.

Ibuprofen is part of a drug class called non-steroidal anti-inflammatory drug (NSAID) and the name Ibuprofen is derived from isobutyl (ibu) propionic acid (pro) phenyl (fen)

Advil is dissolved in the stomach and then is absorbed by the intestinal wall in order to reach the bloodstream Eventually it reaches the areas where the synthesis of the prostaglandin is found. Prostaglandin are the fatty acids which cause the pain found near the damaged tissue. 

Okay so we have covered the background but there are a lot of things that the biology does not cover so do you want to get into the Chemistry portion of this podcast

Segment 2: The Chemistry Behind Advil

Of course, while I had just said ibuprofen is ‘dissolved’ in stomach acid, Ibuprofen is actually not soluble in stomach acid which we are gonna discuss as gastric acid. 

I’ll start with a little background on Ibuprofen: it is a non-polar weak acid with a pH around 4.4. Ibuprofen is most soluble with organic solvents like ethanol, methanol, aceton, and dichloromethane

Well, the non polar ibuprofen is what actually causes it to not dissolve with gastric acid. This is because Polar solutes dissolve in polar solvents and visa versus with nonpolar solutes and solvents. Knowing this principle, and that Gastric Acid is very polar it clearly indicates the nonpolar Ibuprofen will not form a solution with the polar gastric acid, this means no ibuprofen will technically be ‘dissolved’ 

Not only is ibuprofen insoluble but its molecule also has a large carbon chain. This carbon chain will create a great bond strength which is fairly difficult to break. 

The significantly high bond strength is difficult to overcome and in order for the molecule to dissolve, the solvent-solvent bonds must be broken, and solvent-solute bonds need to form. Gastric acid is extremely acidic with a pH of 1-2 and any strong acid will pull apart the intramolecular forces bonding the molecule, which is why acid is so destructive. When the acid interacts with the ibuprofen it will break the bonds just like the acid would to regular food when digested. Because the reaction relies purely on the strength of gastric acid and the ibuprofen is insoluble, 

This process will have a relatively long residence time, which means the reaction occurs at a slower rate. Now why don’t you explain the reaction rate.

This slower rate is actually caused by the high activation energy of ibuprofen. Activation energy is pretty self explanatory, it's the energy it takes to activate or start a reaction. Since we are talking about the reaction rate of Ibuprofen we should talk about the activation energy of it. When it comes to thermodynamically favorable reactions with a high activation energy they theoretically should occur because when the reaction is thermodynamically favorable, it's favored to react.. Going back to ibuprofen, The required temperature for it to begin reacting is around 800 degrees fahrenheit. 

Ibuprofen is a nonselective inhibitor of an enzyme called cyclooxygenase (syclo-oxygen-naise)

This enzyme is required for the synthesis of ibuprofen in the acid pathway

The enzyme plays a major role in getting this reaction to occur.

Because the activation energy of ibuprofen is fairly large the reaction is unlikely to happen at the temperature of our stomach which is around 100 degrees fahrenheit.

The enzyme's job is to create another way for the chemical reaction to occur more rapidly, this alternate path length allows for the reaction to occur at with a lower activation energy as well. 

Without the enzyme it would be likely the ibuprofen wouldn’t react rendering it useless.

Segment 3: Personal Connections

Being an athlete I tend to always be injured and throughout the season to keep me on the court I’m always taking Advil. I have a travel size bottle in all my bags and I would have to sit if it weren’t for having advil. I have taken Advil plenty of times myself but never really understood how it works. Something so commonly used by many people holds a lot of importance. You swallow it with some water and your pain can be relieved for hours. Something so basic actually requires a quite complex process and we both were curious to understand how chemistry played a role in Advil from start to finish.

When I think of Advil, I usually remember all the times I used to take it for headaches. I Have struggled with sleep my whole life, and therefore would always have headaches because headaches can be caused by dehydration, blood flow, and lack of sleep. When we have issues in these certain areas, they become inflamed. Advil has always been there for me with my struggles when I would have migraines every since 2nd grade, and always helped me. Advil’s anti-inflammatory properties help relieve the pain, however there is just so much chemistry involved with it, which makes Advil seem magical. 

Thank you for listening to this episode of Chemistry Connections. For more student-ran podcasts and digital content, make sure that you visit


Music Credits

Warm Nights by @LakeyInspired 




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