Table 1.

Examples of thermosensitive, pH-sensitive and ion-sensitive polymers used for ophthalmic hydrogel formulations.

Type	Polymers	References
Thermosensitive gels	Negative: Pluronics, poly(N-isopropyl acrylamide) Positive: poly(acrylic acid), polyacrylamide, Reversible: poloxamer, chitosan, hydroxyl propyl méthyl cellulose	[30,31,32,33]
pH-sensitive gels	Cellulose acetate and derivatives Carbomer Magrogol Pseudolatex Polymethacrylic acid	[29] [34] [35]
Ion-sensitive gels	Alginate sodium gellan gum (Gelrite®)	[3] [29]