Aspirin

From Chempedia

Habon Mohamed
Abdikafi Ahmed
Fatima Osman
Anab Duale

ASPIRIN: A DERIVATIVE OF SALICYLIC ACID

Aspirin is one of the drugs to come into common usage and is still the most widely used drugs in the world. Each year, more than 40 million pounds of aspirin is produced in the US alone, a rate that translate to about 300 tablets per year for every man, woman and child.¹ According to the Aspirin-Foundation, Aspirin originated as herbal folk medicine and continued to exist as well known painkiller and life saver until today. Aspirin’s role is constantly changing and all the developments of this drug have come from the efforts of many physicians and other researches undertaken by different scientific communities across the world.³ There are vast amount of information accessible on aspirin, but the main focus of this paper will be on the chemical reaction, and properties, formula and structure, usage and side effects of aspirin.

CHEMICAL AND PHYSICAL PROPERTIES

The most important and active ingredient in aspirin is acetylsalicylic acid. ⁸ Acetylsalicylic is a synthetic derivative of compound called salicin. Acetyl salicylic acid occurs as a white crystal, commonly tabular and is odorless or has a faint odor.² Acetyl salicylic acid is fairly stable in dry air conditions; but it is known to gradually hydrolyze to salicylic and acetic acids in moist humid air. This drug is somewhat soluble in water but its solubility is significantly higher in solvents such as alcohol, chloroform and in ether, but only sparingly soluble in absolute ether.⁹ Acetylsalicylic acid has a chemical formula of C₉H₈O₄ with molecular weight of 180.16g, represented by the following structural formula below:

Figure 1. The shape of aspirin and its molecular weight (Reference 3)

SYNTHESIS OF ASPIRIN AND THE MECHANISM BEHIND IT

In order to make aspirin, the following raw materials are needed: phenol C₅H₅-OH, sodium hydroxide (NaOH), carbon dioxide (CO₂), acetic anhydride (CH₃COOCH₃), and hydrogen (H₂).³ In the synthesis aspirin, When the temperature of sodium phenoxide is increased with carbon-dioxide under enough pressure, then the mixture turns to acidic and produces salicylic acid as shown below.¹

Figure 2. (Referenced 1) Then acetylsalicylic acid is synthesized by a chemical reaction called esterification from salicylic acid. Esterification is simply the reaction between a carboxylic acid (-COOH) and an alcohol (-OH) or phenol which is catalyzed, "to form carboxylate ester. In the synthesis of aspirin the -OH group is the phenolic -OH group, attached to ring of the salicylic acid. The acetyl group, -COCH₃ comes from acetic anhydride. The reaction is catalyzed by phosphoric acid." ⁶ as seen below:

MW = 138.12 MW = 102.09 MW = l80.16 MW = 60.05

To understand the mechanism behind the Aspirin as headache medicine and how it wonderfully takes the pain away from our body, it becomes necessary that we understand the enzyme COX-2, a protein normally present in our body cells and whose main assignment is to collect any floating chemicals from the body tissues and send them to the prostaglandins.⁷Aspirin stops COX-2 from performing and doing what it was supposed to be doing in the body tissues and by that mechanism the degree of the pain that is transmitted through the brain is reduced.⁷ Therefore, our pain is reduced that way and we feel better

BENEFITS OF ASPIRIN

Aspirin inhibits enzymes which drive the synthesis of a group of hormone-like substances called Prostaglandins. Prostaglandins are involved in pain transmission to the brain, temperature regulation, and acts as messenger molecules for inflammation.⁷ Therefore, "Aspirin’s suppression of prostaglandins makes it effective for use as pain reliever, fever reducer, and anti-inflammatory agents."⁵ It is also known to prevent heart attack because it functions as blood thinner by inhibiting platelet aggregation (blood clotting cells).⁶ This drug can be administered in form of cream, rectal, and can be taken orally. When taken orally, Aspirin takes 20 to 60minutes to be absorbed by the body depending on dosage, gastric pH, emptying time, dissolution rate and whether it is taken with meals, antacids, or during fasting.⁵

ASPIRIN’S SIDE EFFECTS

"Aspirin has a multitude of side effects including acid-base abnormalities, ringing in the ears (tinnitus), vertigo, hearing loss, kidney failure, gastrointestinal bleeding, and gastritis." ¹⁰Although, aspirin is widely used, there is major risks associated with aspirin, such as Reye’s Syndrome in children and young adults. Reye’s syndrome is a deadly disorder that strikes suddenly without warning.It affects all body organs and can result sudden death.⁴ Whenever Aspirin is taken in excess, it results major consequences that include respiratory sensitivity and alkalosis.¹⁰

Researchers are still studying aspirin to discover if it has other disease prevention benefits. Other studies are being conducted on its interaction with other NSAIDs and other medications, as well as how any interactions may interfere with its benefits. Aspirin has versatile uses and benefits and therefore continues to interest scientist and researchers.

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