Hydrogels for delivery of bioactive agents: A historical perspective☆
Graphical abstract
Section snippets
Research on hydrogels
The number of references published under the research topic of “hydrogel” has increased exponentially during the last decade. According to SciFinder®, the first reference on hydrogel appeared in 1894. Although the hydrogels described during that time period was a colloidal gel of inorganic salts, which are not exactly the same type of hydrogels we are dealing with nowadays, the use of the word “hydrogel” in as early as 1894 is very interesting. Since then, the term “hydrogel” was used to
Hydrogels for drug delivery
Analysis of the references on drug delivery by the index terms resulted in more than 1000 different terms. The most widely used index terms include pharmaceutical hydrogels, dissolution, physical swelling, and controlled release. Despite a large number of references related to hydrogel-based drug delivery systems, however, the actual number of hydrogel-based drug delivery systems or devices approved by the Food and Drug Administration (FDA) is extremely small. The clinically used hydrogel-based
Self-regulated drug delivery systems
One of the holy grails of controlled drug delivery is self-regulated insulin delivery systems. Insulin delivery is not like any other drug delivery where a sustained, long-term release can achieve an intended goal. Insulin release has to occur at the right time in the right amount. Insulin delivery starts with measuring the glucose concentration in the blood or in an environment in equilibrium with that of the blood. Once the glucose level increases, the right amount of insulin has to be
Current and future research on hydrogels
As mentioned above, the number of FDA-approved clinical products based on hydrogels is rather small. There may be many reasons for this, but one of them is that the current approach of hydrogel research for drug delivery is not quite in sync with formulation development. The current approach is to synthesize new smart hydrogels having new properties. Once a new hydrogel is synthesized, then suitable applications are sought out for the hydrogel. Since the new hydrogel was not prepared for any
Mimicking natural systems
One approach of designing a successful clinical formulation is to mimic natural systems. After all, a holy grail of making a self-regulated insulin delivery system is just to mimic the pancreas, a natural system. Mimicking natural systems, however, is not as easy as it sounds, because there are fundamental differences in the way that natural systems are formed and the way that synthetic systems are created, as shown in Fig. 4 [14]. In natural systems, evolution occurs to increase the efficacy,
Acknowledgments
This study was supported in part by NIH through grants CA129287 and GM095879, and Showalter Research Trust Fund.
References (15)
- et al.
Environmentally-sensitive polymer hydrogels
Adv. Drug Deliv. Rev.
(2001) - et al.
Advances in recognitive, conductive and responsive delivery systems
J. Control. Release
(2008) - et al.
In situ gelling stimuli-sensitive block copolymer hydrogels for drug delivery
J. Control. Release
(2008) - et al.
Glutathione-responsive nano-vehicles as a promising platform for targeted intracellular drug and gene delivery
J. Control. Release
(2011) - et al.
Stimuli-responsive LbL capsules and nanoshells for drug delivery
Adv. Drug Deliv. Rev.
(2011) - et al.
A sulfonamide based glucose-responsive hydrogel with covalently immobilized glucose oxidase and catalase
J. Control. Release
(2003) - et al.
Degradation of phospholipid polymer hydrogel by hydrogen peroxide aiming at insulin release device
Biomaterials
(2003)
Cited by (198)
A sustainable and green approach towards the utilization of biopolymers for effective wound dressing applications: A detailed review
2024, Nano-Structures and Nano-ObjectsMarine polysaccharide-based hydrogels for critical materials selective removal and recovery: A review
2023, Coordination Chemistry ReviewsFundamental advances in hydrogels for the development of the next generation of smart delivery systems as biopharmaceuticals
2023, International Journal of PharmaceuticsCurrent state of knowledge on intelligent-response biological and other macromolecular hydrogels in biomedical engineering: A review
2023, International Journal of Biological MacromoleculesPreclinical and clinical study of polysaccharide-based hydrogels
2023, Polysaccharide Hydrogels for Drug Delivery and Regenerative MedicineCurrent design and advances of hydrogel for retinal tissue engineering and regenerative medicine
2023, Hydrogels for Tissue Engineering and Regenerative Medicine: From Fundamentals to Applications
- ☆
This review is part of the Advanced Drug Delivery Reviews theme issue on "25th Anniversary issue—Advanced Drug Delivery: Perspectives and Prospects".