Aspirin is a weak acid with a pka of 3.5 that is absorbed more effectively in the stomach than the small intestine. The ph of your stomach is around 1.5 and the ph of your small intestine is approximately 6.0. Is aspirin absorbed more readily when it is protonated or deprotonated? What is the approximate ratio of conjugate base to acid when it is absorbed more readily?
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5. At a pH higher than the pKa, aspirin will be deprotonated and in its neutral form, which is more easily absorbed. ** Show more…
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Aspirin, shown below, is a weak acid, with a pKa = 3.5. When ingested, part of it is absorbed into the blood in the stomach, where pH = 1.5. In order to be absorbed, aspirin needs to cross the plasma membrane of the cells lining the stomach. Recall that the membrane is based on a lipid bilayer, whose interior is very nonpolar. What is the fraction of the aspirin molecules that are in a state of ionization (or protonation) that can cross the bilayer in the stomach?
Brooke S.
Aspirin is an acid with a $\mathrm{p} K_{\mathrm{a}}$ of $3.5 ;$ its structure includes a carboxyl group. To be absorbed into the bloodstream, it must pass through the membrane lining the stomach and the small intestine. Electrically neutral molecules can pass through a membrane more easily than can charged molecules. Would you expect more aspirin to be absorbed in the stomach, where the pH of gastric juice is about $1,$ or in the small intestine, where the pH is about $6 ?$ Explain your answer.
The pKa of Acetylsalicylic acid is 3.5. A) What is the ratio of ionized/unionized of the drug in the stomach where pH is 1? B) What is the ratio of ionized/unionized in the intestine where pH is 6? C) Based on the above calculations, where is aspirin absorbed within the body?
Ronald P.
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