Why does the structure of gramicidin, shown below, only allow topical use as an antibiotic?

Question

Quizplus · Accepted Answer

Gramicidin creates channels in cell membranes, which allows it to disrupt the normal function of bacterial cells. However, this also makes it toxic to human cells if taken orally or systemically. Therefore, it can only be used topically, where its effects are localized and not absorbed into the bloodstream. Gramicidin does not affect nucleic acid synthesis, cell wall synthesis, or contain beta lactam rings, so choices A, B, and C are incorrect. Similarly, Gramicidin does not directly interfere with DNA synthesis, so choice D is also incorrect.

Why Does the Structure of Gramicidin, Shown Below, Only Allow