Hydrogels are natural or synthetic polymeric networks, insoluble in water, or sometimes found as
colloidal gel where the dispersion medium is water. Hydrogels can absorb approximately 90% water and are
regarded as superabsorbent materials; hence these resemble the natural living tissues more than any other biological-
based materials. Because of their ability to absorb water, they are used to investigate the properties of
swollen polymer networks and have wide applications in different fields such as contact lenses, drug delivery
systems for proteins, and many others. To make them biodegradable, labile chemical bonds are introduced in
the main backbone through crosslinking. These unstable bonds can then be broken down by various agents
chemically, physically, or enzymatically, generally by hydrolysis or through some controlled parameters. Hydrogels
are frequently used in the medical field. For instance, pH and temperature-sensitive hydrogels may be
used in the targeted drug delivery which have been explained in detail in the current review. The other applications
of hydrogels are also explained with regard to personal health care products, biomedical, bio-separation,
wound healing, tissue engineering, and drug delivery, etc., which make them promising materials in pharmaceutics.
They are also used in agriculture and environmental remediation. The purpose of this review is to expose
their salient features and biomedical applications.