Hydrogel nanoparticles in drug delivery

Hydrogel nanoparticles in drug delivery
Mohammad Reza Salehi Kia,^1,*
Introduction: Hydrogels are hydrophilic three-dimensional networks. They have cross links which swell in contact with water without being solved. These compounds can have different forms such as slab, microparticle, nanoparticle, coating structure, and film. Due to different forms, hydrogels can be used in different fields of research including biosensors, tissue engineering, separation of biomolecules or cells, and regulation of bioadhesion of materials. Materials which have hydrogel nanoparticle structure, represent the characteristics of both hydrogels and nanoparticle simultaneously. Hydrogel nanoparticles have many applications. The most important application them is cellular-target therapy. In addition, they can be used in controlled releae of proteins such as Lysozyme, Albumin, and Immunoglobulin.
Methods: This study is a library research. It seeks to collect general information and scientific researches on hydrogels.
Results: Hydrogels are polymeric networks with three-dimensional structures which can absorb a lot of water or bioliquides because of existence of hydrophilic groups like hydroxid in polymers which form the structurr of hydrogel. The gel will be hydrate in terms of the nature of water environment and the structure of polymer and it can be reach more than ninety percent by weight of the polymer. Water content of hydrogels plays a pivotal role in determination of the whole characteristics of polymeric network. Therefore, they have distinctive features which differentiate them from hydrophobe polymeric networks. It is worth mentioning that the preparation of hydrogels is significantly milder and in addition to gel formation at ambient temperature, organic solvents are rarely used in their production process. Hydrogels, especially those used in biomedicine and drug delivery, must have acceptable biocompatibility and biodegradability. The structure of the hydrogel network can be macroporous, microporous, or nonporous. Macroporous hydrogels have large pores in the dimensions of 1, 0, up to 1 micrometer. These hydrogels release the drug trapped inside their pores through a mechanism which depends on the drug diffusion coefficent. Microporous hydrogels have small pores in the demension of 10 up to 100 nanometer. They release the drug trapped inside their pores through diffusion processes and molecular convection flow. Nonporous hydrogels are consisted of seive-like structures in the demensions of macromolecules with pores of 1 up to 10 nanometer which are formed by making cross links in monomeric chains. In these structures, drug release occurs only through the diffusion mechanism.
Conclusion: Hydrogel-based drug delivery, among different applications of hydrogels, has gained significant attention. It is a field in progress. Obvoiusly hydrogels can protect drug from internal destructive factors such as enzymes and PH changes. Their porosity causes drug loading in gel matrix and their release with predetermined speed. Encouraging applications of hydrogels in the fields of medicine and pharmacy include materials controlling enzyme activity, destabilizing factors of double layer phospholipids, materials controlling reversible cell-binding, nanoreactors with the possibility of accurate inclusion of active groups in three-dimensional space, intelligent microfluids with responsive hydrogels, and energy conversion systems.
Keywords: nanoparticles, hydrogel nanoparticles, drug delivery, medicine, polymer