Synthesis of Aspirin Post Lab Discussion

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Questions and Answers

What is the main mechanism of action of acetylsalicylic acid?

Decreases central synthesis of PGE2

Irreversible acetylation of COX-1 isoenzyme (correct)

Increases peripheral synthesis of PG

Enhances the conversion of arachidonic acid to PG

What happens to acetylsalicylic acid in aqueous media?

Becomes stable

Transforms into a different NSAID

Becomes more potent

Decomposes rapidly (correct)

Which condition is NOT an indication for the use of acetylsalicylic acid?

Allergic rhinitis (correct)

Pain and fever

Acute polyarthritis rheumatica

Rheumatoid arthritis

What is the effect of ASA converting to salicylic acid inside the body?

Anti-inflammatory effect Signup and view all the answers

How does acetylsalicylic acid affect the body's response to interleukin 1?

Alters the response Signup and view all the answers

Which of the following is NOT a therapeutic benefit of acetylsalicylic acid?

Antihistamine Signup and view all the answers

What is the reason behind the decreased gastrointestinal (GI) distress associated with Salsalate compared to Aspirin?

Salsalate is relatively insoluble in the stomach, so it is not absorbed until it reaches the intestine. Signup and view all the answers

Which of the following is a contraindication when using Warfarin along with Aspirin?

High protein binding of Aspirin leading to displacement of Warfarin Signup and view all the answers

What therapeutic benefit does Diflunisal offer that makes it a preferred choice in certain conditions despite causing gastrointestinal distress?

Diflunisal provides a longer duration of action than Aspirin. Signup and view all the answers

Why is Choline Salicylate considered extremely soluble?

Its high solubility allows for easier absorption in the body. Signup and view all the answers

Which of the following best describes the chemical property of Sodium Salicylate that makes it advantageous for patients with Aspirin allergy?

Sodium Salicylate has a lower tendency to cause gastrointestinal (GI) irritation. Signup and view all the answers

What distinguishes Salicylamide from Aspirin, making it a suitable alternative for patients sensitive to Aspirin?

Salicylamide gets converted into a different compound that is less irritating to the stomach. Signup and view all the answers

Which statement about NSAIDs is correct?

NSAIDs possess a free carboxyl group that binds to the active site of cyclooxygenases. Signup and view all the answers

Which of the following is a ketone prodrug that is metabolized to an active NSAID?

Ketorolac Signup and view all the answers

Which of the following is the primary undesirable side effect of NSAIDs associated with the inhibition of thromboxane and prostacyclin?

Gastrointestinal bleeding Signup and view all the answers

Who first introduced the therapeutic benefits of salicylates (aspirin) in 1763?

Reverend Edward Stone Signup and view all the answers

What is the IUPAC name for aspirin?

2-acetoxybenzoic acid Signup and view all the answers

Which of the following statements about the chemical properties of aspirin is correct?

It has a melting point of around $134-140^\circ\mathrm{C}$ and a boiling point of $140-284^\circ\mathrm{C}$. Signup and view all the answers

Study Notes

Acetylsalicylic Acid (Aspirin)

Unstable in aqueous media and decomposes rapidly in solutions of ammonium acetate or of the acetates, carbonates, citrates or hydroxides of the alkali metals
Mechanism of action: decreases peripheral synthesis of PG by blocking the conversion of arachidonic acid to PG via the inhibition of the COX isoenzymes
Inside the body, ASA is converted to salicylic acid which is responsible for its anti-inflammatory effect

Anti-inflammatory and Antipyretic Effects

Inhibition of COX reducing the central synthesis of PGE2 in the hypothalamic area of the brain that regulates body temperature
Increase heat elimination of the body in febrile patients via the mobilization of water and consequent dilution of the blood
Perspiration causing cutaneous dilation alter response of the body to interleukin 1 (endogenous pyrogen)

Antiplatelet Action

Irreversible acetylation of Ser-530 of the COX-1 isoenzyme

Dosage

Adults:
- Oral: 300-1000 mg every 4 h; max 4 g a day for pain and fever
- Oral: 1 g 6 times a day; max 8 g a day for acute polyarthritis rheumatica
- Oral: 0.5-1 g 6 times a day; max 8 g a day for rheumatoid arthritis
- Compounds with controlled release: 1 g 2-3 times a day, if necessary 6 times a day
Intramuscular or intravenous (lysine acetylsalicylate): 500 mg, 1-4 times a day

Contraindications

Antacids: decreases ASA absorption
Warfarin: due to high CHON binding of ASA; displacement of warfarin bleeding

Salsalate (Salicyl Salicylic Acid)

Ester produced by the combination of 2 salicylic acid molecules
Less GI distress due to being relatively insoluble in the stomach
Converted to 2 molecules of salicylic acid

Diflunisal (DOLOBID)

Not metabolized to salicylic acid due to high CHON binding
Causes GI distress
Mainly used in the treatment of OA, RA and postoperative pain due to longer duration of action
CI in patient with kidney failure leads to nephrotoxicity

Sodium Salicylate

ASA + NAHCO3 (EQUAL MOLE RATIO WITH SALT)
DISADVANTAGE: DECREASE GI ABSORPTION, INCREASED EXCRETION
ADVANTAGE: LESS GI DISTRESS
MAINLY GIVEN TO PATIENT WITH ASA ALLERGY

Other Salts of Salicylic Acid

Mg Salicylate (MOBIDIN, MAGAN)
Na thiosalicylate (REXOLATE)
Choline salicylate (ARTHROPAN)

Salicylamide

Benzamide derivative of ASA
For patients with ASA sensitivity
Excreted exclusively as either gluconamide or sulphate

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Description

Explore a post lab discussion on the synthesis of aspirin, focusing on NSAIDs (Nonsteroidal Anti-Inflammatory Drugs) and their properties. Learn about the chemical structure and interactions of NSAIDs with active sites, including the role of ketone prodrugs and carboxylic acids.