The Role of Chemistry in the Development of Aspirin and Paracetamol, Essay Example

Introduction

Aspirin is a pain medication that is commonly used for headaches and other minor aches in the modern era. However, the molecule responsible for this curative reaction has been utilized for centuries, although in a less pure form. The first use of acetylsalicylic acid, the active ingredient in aspirin, can be traced back to ancient Egypt (Mann & Pulmmer 1991). This primitive medication was derived from willow and similar plants as early as 400 B.C.E. The Egyptian people had become aware of the medical applications of these plans as consequence of a series of observations that linked the use of the plan with pain reduction. Therefore, when modern pharmacologists wished to develop a more effective rain reliever, they were aware that certain molecules could be extracted from these plants in order to develop a purer curative compound. Over time, scientists worked to understand how to create more effective pain relievers and utilized this knowledge to create new compounds. Furthermore, scientists have put forth much effort to determine how aspirin and related compounds interact with the human body in order to elucidate a greater amount of information regarding the usefulness of this medical intervention.

Chemical Structures and Reactions

As the need for pain relievers became more common, chemists worked to determine how to synthesize acetylsalicylic acid to allow this compound to become more widely available and to be sold for a cheaper price (MTU n.d.). In 1853, a man by the name of Charles Frédéric Gerhardt synthesized this compound for the first time by creating a chemical derivative of acetyl chloride and sodium salicylate. The synthesis of this compound is demonstrated below:

The derivation of acetyl salicylic acid occurs as a result of a chemical reaction between acetic anhydride and salicylic acid. Acetic acid forms as a byproduct, indicating that the resulting mixture of acetyl salicylic acid and acetic acid must be separated so that acetyl salicylic acid could be utilized in medical applications. The hallmark of this chemical reaction is that the hydroxyl group on the salicylic acid is replaced by a carboxyl. It is this property that makes aspirin an effective pain killer. Heat is necessary to help the reaction proceed. The goal is to ensure that the resulting acetyl salicylic acid product is pure as possible, as this will reflect the efficacy of the medicine. Purity can be examined by completing the ferric chloride test as a color indicator.

Once the chemical structure of acetyl salicylic acid was known, it became easier for other scientists to determine additional methods to isolate it more efficiently. A pharmaceutical company by the name of Bayer began to market this more highly purified medication in place of other less effective painkillers in 1899. At this point, acetyl salicylic acid became known as aspirin. Early use of the drug was not well understood and it is likely that it was utilized to treat many illnesses for which it had not been tested. As a consequence, there were many deaths related to the use of the drug that led to the need for further drug development in addition to an understanding of how the drug interacts with the human body.

In response to these problems, Paracetamol, also known as acetaminophen, was produced (Shanbhag n.d.). Paracetamol is synthesized from p-Aminophenol and acetic anhydride. These two chemicals combine to form acetaminophen and acetic acid as a side product. The functional groups are important to the functionality of acetaminophen, a hydroxyl and amino group, are derived from the p-Aminophenol molecule. A carboxyl group is then added to this base from the acetic anhydride. This chemical reaction is as follows:

The Evolution of Chemistry Related to Drug Development

Pharmaceutical companies are now the main driving force behind drug development. While the development of drugs such as aspirin have been evidence-based, many pharmaceuticals were created to purposely treat disorders for which they are not currently used. Furthermore, to increase the yield of drugs created and therefore profit, pharmaceutical companies have been known to create various drugs with similar chemical properties in bulk for the specific purpose of determining which drug will be the most effective for a particular application. Paracetamol was created in this manner.

The possibility for the synthesis of paracetamol first arose when scientists synthesized acetanilide, the first aniline derivative that would found to have pain killing properties. Despite this medication’s efficacy as a pain killing medication, it had many toxic side effects that resulted in its eventual disuse. The chemical structure for acetanilide is shown below:

Even though this chemical was not usable, it provided chemists with the evidence necessary to gain an understanding of the compounds that could practically allow for pain relieving capabilities (Vane 1994). As a consequence, scientists came to understand that the amino group, carboxyl group, and benzene ring was somehow related to the ability for the chemical to treat pain. Therefore, several variations of this chemical were synthesized and tested to determine which would have the greatest pain reducing potential accommodated by the smallest potential for side effects. Following the synthesis and understanding of Paracetamol, scientists concluded that an additional hydroxyl group would be necessary to reduce the toxic impacts of its predecessor, aniline.

Conclusion

The development of aspirin and Paracetamol started with a basic observation made by the ancient Egyptians, who found that certain plants could be consumed for their painkilling properties. Scientists later recalled the use of these plants and aimed to determine whether the compound that held these medicinal properties could be isolated. After conducting a series of synthesis experiments, it was found that not only could acetylsalicylic acid be extracted from these plants, it could be created from acetic anhydride and salicylic acid as well. Following the development of acetanilide, chemists recognized that more potent pain killers could be created. Since this compound had toxic effects, scientists performed experiments that would modify this compound until a reasonable non-toxic replacement was found. This ultimately led to the development of Paracetamol with the mere addition of a hydroxyl group.

While both aspirin and Paracetamol are not without their toxic effects, both molecules offer a significant enhancements compared to their predecessors. Our modern understanding of chemistry has significantly increased our ability to access better medications and it is likely that scientists will continue to build upon our current knowledge of pharmacology to create even more effective medications in the future.

Bibliography

Mann CC, Pulmmer ML 1991, The Aspirin Wars, Knopf, New York.

MTU n.d. Preparation of Acetylsalicylic Acid. Available from: <http://www.chemistry.mtu.edu/~kmsmith/SYP/Student/Tuesday/Aspirin.pdf>. 19 February 2015.

Shanbhag n.d. Synthesis of Acetaminophen. Available from: <http://rene.souty.free.fr/IMG/pdf/ParacetamolProtocolFLORIDacetaminophen.pdf>. 19 February 2015.

Vane JR 1994, ‘Towards a better aspirin’, Nature vol. 367, pp. 215-216.