pKa = 2.1; pH = 2.0 (stomach); pH = 6 (intestines)
= 99.98741233 % ionized in intestines
= 0.012587669 % non-ionized in
= 55.7311634 % non -ionized in stomach
=44.2688366% ionized in stomach
Predict whether this compound will be absorbed by passive diffusion better in the stomach, or intestines?
Explain the reasoning for your conclusion
To predict whether a compound will be absorbed better in the stomach or intestines through passive diffusion, we need to consider the ionization state of the compound in each environment.
The percentage of ionized and non-ionized forms of the compound can be estimated using the Henderson-Hasselbalch equation:
% ionized = 100 / (1 + 10^(pKa - pH))
For the intestines (pH = 6 and pKa = 2.1):
% ionized = 100 / (1 + 10^(2.1 - 6)) = 99.98741233%
For the stomach (pH = 2 and pKa = 2.1):
% ionized = 100 / (1 + 10^(2.1 - 2)) = 44.2688366%
From the calculations above, we can see that the compound is almost completely ionized in the intestines (99.987% ionized) and less ionized in the stomach (44.269% ionized).
Passive diffusion relies on the compound being in its non-ionized form to cross cell membranes more easily. The non-ionized form of a compound is typically more lipophilic, which allows it to cross biological membranes more readily.
Considering that a higher percentage of the compound is in the non-ionized form in the stomach (55.731% non-ionized) compared to the intestines (0.0126% non-ionized), we can conclude that the compound will be absorbed better in the stomach through passive diffusion.
In summary, the compound will have a higher absorption rate through passive diffusion in the stomach compared to the intestines due to its higher non-ionization percentage in the stomach.