TABLE 1.

Advantages and limitations of strategies for small hydrophilic molecules.

	Advantages	Limitations
Micro/nanocapsules	✓ High drug encapsulation efficiency ✓ Good biocompatibility ✓ High modifiability	✓ Instability in plasma ✓ Leakage during storage ✓ High cost ✓ Toxicity related to solvents
Physical adsorption	✓ Easy operation ✓ High biocompatibility ✓ Less toxicity related to solvents and chemical crosslinking agents	✓ Initial rapid drug release ✓ Less controllability
Covalent conjugation	✓ Controllable drug loading ✓ Enhanced stability ✓ Stimuli-responsive release	✓ Toxicity related to solvents and coupling agents