**Core Concept**
Pyridostigmine is a cholinesterase inhibitor used in the management of myasthenia gravis, a chronic autoimmune disorder characterized by muscle weakness and fatigue. The preferred pharmacokinetic properties of pyridostigmine over neostigmine are crucial in its clinical application.

**Why the Correct Answer is Right**
Pyridostigmine is longer-acting than neostigmine due to its slower onset of action and longer duration of effect. This allows for more sustained improvement in muscle strength and reduced dosing frequency, making it more convenient for patients. The pharmacokinetic differences between these two drugs are primarily attributed to their distinct chemical structures and rates of hydrolysis by cholinesterase enzymes.

**Why Each Wrong Option is Incorrect**
**Option A:** Pyridostigmine does cross the blood-brain barrier (BBB), although its effects on the central nervous system are minimal. This option is incorrect because the BBB penetration is not a critical factor in its preference over neostigmine in myasthenia gravis.
**Option C:** This option is incorrect as it contradicts the correct answer. While pyridostigmine does have some ability to cross the BBB, its primary advantage over neostigmine lies in its longer duration of action, not its ability to cross the BBB.
**Option D:** Pyridostigmine is actually longer-acting than neostigmine, making this option incorrect.

**Clinical Pearl / High-Yield Fact**
When selecting a cholinesterase inhibitor for myasthenia gravis, remember that pyridostigmine's longer duration of action allows for reduced dosing frequency, improving patient compliance and quality of life.

**✓ Correct Answer: B. Longer acting than neostigmine**