Antacids Acetylsalicylic acid

Each Alka-Seltzer tablet contains 1916 mg of sodium bicarbonate, 1000 mg of citric acid (Fig. 9.1.2), and 325 mg of aspirin or acetylsalicylic acid (Fig. 9.1.3). Bromo Seltzer also contains sodium bicarbonate and citric acid as well as acetaminophen (Fig. 9.1.4). Several equilibria describe the action of bicarbonate-based antacid tablets. First of all, sodium bicarbonate dissolves completely in aqueous solution to generate sodium ions and bicarbonate ions ... 

The reactions in Table 13.8 show that carbon dioxide is a common product in many neutralization reactions. This is clearly displayed when a drop of vinegar (acetic acid) is added to baking soda (sodium bicarbonate). Some aspirin includes an antacid in their formulation to neutralize some of the acidity imparted by the aspirin (acetylsalicylic acid). These are commonly referred to as buffered aspirins. 

Many aspirins are advertised as buffered aspirin, and this has led to the misunderstanding that these aspirin are buffers. In reality, as mentioned previously, buffered aspirins actually contain an antacid to reduce the problems brought on by the effects of aspirin, which is the acid called acetylsalicylic acid. Because of its widespread use and importance to humans, let s take an extended look at the history and chemistry of aspirin. 

Aspirin (acetylsalicylic acid) is absorbed from the stomach in the free (non-ionized) acid form. If a patient takes an antacid that adjusts the pH of the stomach contents to 2.95 and then takes two 5-grain aspirin tablets (total 0.65 g), how many grams of aspirin are available for immediate absorption from the stomach, assuming immediate dissolution Also assume that aspirin does not change the pH of the stomach contents. The pZ of aspirin is 3.50, and its formula weight is 180.2. 

Medicine pain killer and fever reducer (magnesium acetylsalicylate) antacid to neutralize stomach acid (magnesium hydroxide magnesium phosphate magnesium silicate) laxative to loosen the bowels... 

---