Table 1.

List of representative articles employing pH responsive materials.

Stimulus	Material	Drug	Reference
pH	Chitosan hydrogels	Anti-inflammatory factors and antibiotics	[58]
	HEMA (2-hydroxyethyl methacrylate)/DMAEMA (dimethylaminoethyl methacrylate		[59]
	Mesoporous bioglass (MBG) with hydroxyapatite (HAp)	Metformin hydrochloride (MH)	[60]
	Mesoporous ceramics with hydroxypatite (HAp)	Levofloxacin (Levo)	[61]
	Liposomes	Antagomir-10b y Paclitaxel (PTX)	[63,64,65]
	Hydrogels based on cytosine (C) and guanosine (G) modified hyaluronic acid (HA) via hydrogen bonding, with 1,6-hexamethylenediamine (HMDA)		[66]