**Core Concept**
The distribution of drugs in tissues is influenced by various factors, including lipid solubility, protein binding, and the presence of specific transport mechanisms. Drugs that are highly lipid-soluble tend to distribute extensively into fatty tissues, while those that are highly protein-bound tend to be confined to the vascular compartment.

**Why the Correct Answer is Right**
Ephedrine is a sympathomimetic drug that is primarily metabolized by monoamine oxidase (MAO) in the liver. Its distribution into bone tissue is limited due to its low lipid solubility and high protein binding. In contrast, the other options are known to accumulate in specific tissues: chloroquine in the eyes, digoxin in skeletal muscle, and minocycline in adipose tissue.

**Why Each Wrong Option is Incorrect**
**Option A:** Chloroquine is known to accumulate in the eyes due to its lipophilicity and the presence of lysosomes, which can trap the drug. This leads to the characteristic retinal toxicity associated with chloroquine therapy.
**Option C:** Digoxin is a cardiac glycoside that is primarily distributed into skeletal muscle, where it exerts its inotropic effects. Its high affinity for cardiac muscle cells allows it to accumulate in this tissue.
**Option D:** Minocycline is a lipophilic tetracycline antibiotic that can distribute extensively into adipose tissue. Its ability to penetrate into fatty tissues is an advantage in treating certain types of infections.

**Clinical Pearl / High-Yield Fact**
When considering the distribution of drugs in tissues, it's essential to remember that lipid solubility and protein binding are key determinants of tissue accumulation. Drugs with high lipid solubility tend to distribute into fatty tissues, while those with high protein binding tend to be confined to the vascular compartment.

**✓ Correct Answer: B. Ephedrine - bone**