Isolation of acetylsalicylic acid from aspirin tablets lab report

January 23, 2020

Abstract

Aspirin is an over the counter, nonsteroidal anti- inflammatory drug that can temporarily relieve symptoms such as migraines, aches, and pain. It can also prevent blood clots or reduce the risks of having a heart attack. In this experiment we used willow bark, ethanol, iron chloride, acetylsalicylic acid, salicylic acid, acetic acid, and an aspirin tablet in order to synthesize aspirin. Salicylic acid had the pH of 5 with lower acidity. Salicylic acid, is less acidic which means its less harmful to the stomach when compared to aspirin tablets because the tablet have higher acidity (pH 3) which can cause damage to the stomach lining if too acidic.

Introduction

With an estimated world-wide consumption of 40[thin space (1/6-em)]000 metric tons per year, aspirin (acetylsalicylic acid) which was discovered in 1853, is still one of the most prominent and widely used medicines with an incredible spectrum of properties. 1 Apart from its exceptional analgesic, anti-pyretic, and anti-inflammatory properties, it is commonly used in the primary and secondary prevention of cardiovascular diseases. 2

Aspirin is typically administered via the oral route, but unfortunately possesses a number of undesired side effects in long-term use that are mainly related to its acidity and low bioavailability. Aspirin is only sparingly soluble in water (0.33 g in 100 mL) or in the acidic environment of the stomach, resulting in undissolved particles adhering to the gastrointestinal mucosea and causing topical irritation and gastric distress. 3 Once absorbed in the small intestine, acetylsalicylic acid is rapidly metabolized to its main metabolite salicylic acid , thereby irreversibly acetylating and inhibiting COX-1 oxygenase. 4 Like aspirin , salicylic acid itself is also part of the non-steroidal anti-inflammatory drug (NSAID) family and is frequently found in a wide range of medical and cosmetic formulations such as skin-care products or sunscreens. 5 Apart from problems related to the poor solubility of aspirin , the bitter taste of acetylsalicylic acid is another major drawback, with the required dosage of aspirin leading to tablets that are notoriously hard to swallow.

Procedure

The experiment was completed in triplicate meaning steps done in well A1, were also done in B1 and C1. The materials used were a 24- well plate, pipettes, willow bark, litmus paper, ethanol, iron chloride, acetylsalicylic acid, salicylic acid, acetic acid and an aspirin tablet. In part 1 the procedure, consisted of the extraction of salicylic acid. In the first step of Part 1, A1 on the 24-well plate was half-filled with willow bark then the pipette was used to cover the bark with ethanol. A timer was set to 15 minutes to allow the bark to soak. In Part 2 of the experiment 0.5g of acetylsalicylic acid was added to well A2 on the 24-well plate. 50 drops of the ethanol was added with a pipette using the end of the pipette to stir after the ethanol was placed in all three wells. Thereafter each solution was then tested with litmus paper. In part 3 of the experiment, using a pipette one drop of iron chloride solution was added to the acetylsalicylic acid along with the salicylic acid mixtures in wells A2 and A3. In part 4 of the experiment a pipette was used to extract the ethanol from the willow bark in A1 once the 15 minutes were up. 5 drops of ethanol was added to well A4, then the ph was tested with the result of 5. Lastly 1 drop of iron chloride was added to well A1. In part 5 of the experiment using a pipette 5 drops of the willow bark ethanol was added to well A4 following 1drop of iron chloride and 15 drops of acetic acid then stirred with the end of the pipette. The observation was a strong vinegar like smell and brown color to the solution. In part 6 of the experiment an aspirin was crushed and weighed (2.24g). 0.25g of crushed aspirin was poured into well A6, and 50 drops of ethanol was added and stirred into well A6. The pH of the mixture was tested and resulted in pH4. Lastly one drop of iron chloride was added to the well changing the mixtures color from white to light yellow.