Table 3.

Comparison of the properties of CD-containing hydrogels loaded with drugs [74,75,76,77,78,79].

Property	Physical Cross-Linked Hydrogel	Chemical Cross-Linked Hydrogel
Size of guest molecules	Small molecules (lipophilic)	Small molecules (lipophilic)
Drug loading strategies	Encapsulation	Encapsulation
Drug release speed	Can be controlled	Can be controlled
Drug release possible mechanisms	External stimulus; competition of external molecules	External stimulus; competition of external molecule
Duration times	Hours to days	Days to months
Drug delivery characteristic	High drug loading effectivity; low chance of drug deactivation	High drug loading effectivity; low chance of drug deactivation
Potential application	Drug delivery systems, injectable, wound dressings	Transdermal drug delivery, injectable, implantable, oral/ophthalmic drug carrier
Advantages	Non-toxic; cross-linking is reversible	Strong mechanical strength; the pore size can be adjusted; the variety of synthesis methods; difficult to degrade
Disadvantages	Low mechanical strength; difficult to adjust the pore size	Potentially toxic; no cross-linking is reversible