What is the pH range of gastric fluids which primarily aids in weak acid absorption?

The pH range of gastric fluids that primarily aids in weak acid absorption is indeed between 1.5 and 2.5. This highly acidic environment is crucial for the effective solubilization and absorption of weak acids. When the pH is within this range, weak acids can exist mostly in their non-ionized form, which is more readily absorbed through the gastric mucosa.

Weak acids, such as aspirin or other non-steroidal anti-inflammatory drugs, have better absorption in acidic environments because their protonated forms are neutral, allowing them to pass through lipid membranes more easily compared to their ionized counterparts. As the pH becomes higher, such as in the ranges of the other choices, the ability of weak acids to stay non-ionized decreases significantly, resulting in lower absorption.

Thus, the pH range of 1.5 - 2.5 is optimal for the absorption of weak acids, providing the necessary conditions for these drugs to be adequately absorbed into the systemic circulation from the stomach.