True or False: Neostigmine is capable of crossing the blood-brain barrier.

Neostigmine is classified as a reversible acetylcholinesterase inhibitor, primarily used in the treatment of myasthenia gravis and to reverse the effects of neuromuscular blocking agents in anesthesia. Its chemical structure does not allow it to cross the blood-brain barrier effectively, which is mainly due to its quaternary ammonium structure. This structure makes it highly polar, preventing it from permeating lipid membranes, including those that form the blood-brain barrier.

Because it does not enter the central nervous system, neostigmine primarily exerts its effects peripherally. This characteristic limits its use for conditions requiring central nervous system penetration, such as cognitive disorders. Therefore, stating that neostigmine is capable of crossing the blood-brain barrier is incorrect, which aligns with the provided answer of "False."