A Brief Review on Hydrogel

 

Vinod Matole¹, Pradip Digge²*

¹DSTS Mandal’s College of Pharmacy, Solapur.

²Tatyaraoji More College of Pharmacy, Omerga.

 

ABSTRACT:

Hydrogels are water-swollen polymeric materials that maintain a distinct three-dimensional structure. The term “hydrogel” implies a material already swollen in water, while in a true sense hydrogel is a cross-linked network of hydrophilic polymers. They possess the ability to absorb large amounts of water and swell, while maintaining their three-dimensional (3D) structure. Depending on the size and density of the mesh, it can carry protein molecules between 14,000 and 1,50,000 Daltons. The traditional methods of hydrogel synthesis were limited in the control of their detailed structure, but novel approaches based on genetic engineering and hybrid hydrogels, have considerably enhanced this research. As a result, the application potential of hydrogels, in addition to traditional areas such as biomaterials and drug delivery systems, has expanded to other fields, such as microfluidics a nanotechnology.

 

 

 

INTRODUCTION:

Hydrogels are water-swollen polymeric materials that maintain a distinct three-dimensional structure. There is a wide variety of the design options for the preparation of hydrogels of different structures and properties. The traditional methods of hydrogel synthesis were limited in the control of their detailed structure, but novel approaches based on genetic engineering and hybrid hydrogels, have considerably enhanced this research. As a result, the application potential of hydrogels, in addition to traditional areas such as biomaterials and drug delivery systems, has expanded to other fields, such as microfluidics a nanotechnology.

 

In comparison to other synthetic biomaterials, hydrogels resemble living tissues closely in their physical properties because of their relatively high-water content, soft and rubbery consistency. Hydrogels show minimal tendency to adsorb proteins from body fluids because of their low interfacial tension. The term “hydrogel” implies a material already swollen in water, while in a true sense hydrogel is a cross-linked network of hydrophilic polymers. They possess the ability to absorb large amounts of water and swell, while maintaining their three-dimensional (3D) structure.

 

Types of Hydrogels:

1) In-situ gel

2) pH sensitive gel

3) Temperature sensitive gel

4) Ionic sensitive gel

5) Osmotic sensitive gel

6) Homo-polymer gel

7) Co-polymer gel

 

There are various types of gel available and formulated according to need.

 

In-situ Gel:

In-situ is Latin phrase which is translated literally as in position (at site). In-situ gel is drug delivery systems that are in solution form before administration in the body, but once administered, undergo gelation in situ, to form a gel. The formation of gels depends on factors like temperature modulation, pH change, presence of ions and ultra violet irradiation, from which the drug gets released in a sustained and controlled manner.

 

Approaches of in-situ gelling system: -

i)   Stimuli-responsive in situ gel system

      (Temperature, pH)

ii) Osmotically induced in situ gel systems

      (Ion‐activated systems)

iii)           Chemically induced in situ gel systems

      (Ionic, Enzymatic cross linking, Photo-polymerization.)

 

Evaluation of In-situ Gel:

1) In-vitro floating studies:

(for gastro-retentive in-situ gel):

It is the measurement of time required for the gel to float after adding in the solution, known as floating lag time. And also, the duration of floating, known as total floating time.

2) Viscosity measurement of the in-situ gel:

Viscosity is measured by Brookfield viscometer.

3) Determination of drug content:

Drug content is measured by UV-vis spectroscopy.

4) Swelling Index:

 

Swelling index =   W2-W1   *100    

                                   W1      

Where,

W1= Initial wt. of gel

W2= wt. of swollen matrix gel 20

 

5) In-vitro drug release:

Invitro drug release is calculated by IP apparatus-II covered with muslin cloth.

 

6) Stability study:

Stability study is done by accelerated stability study.

 

Advantages of in-situ gel:

·       Ease of administration.

·       Improved local bioavailability.

·       Reduced dose concentration.

·       Reduced dosing frequency.

·       Improved patient compliance and comfort.

·       Simple formulation and manufacturing so less investment and cost.

 

Disadvantages of in-situ gel:

·       Low mechanical strength.

·       Hard to handle.

·       Difficult to sterilize.

·       Non-adherent.

 

Application of in-situ gel:

·       New researchers have demonstrated that a gel composed of small, woven protein fragments can successfully carry and release proteins of different sizes to different targets in the body.

·       It is enabling the delivery of drugs such as insulin and trastuzumab (A monoclonal antibody) (protein) often used to treat breast and ovarian cancer, hormones, growth factors as well as eye medications.

·       Furthermore, one can control the rate of release of active ingredients from hydrogel by changing the density of the gel, allowing for continuous drug delivery over a specific period of time.

·       A newly introduced gel, known as a "nanofiber hydrogel scaffold," enables, over hours, days or even months, a gradual release of the proteins from the gel, and the gel itself is eventually broken down into harmless amino acids (the building blocks of proteins).

·       Peptide hydrogels are ideally suited for drug delivery as they are pure, easy to design and use, non-toxic, bio-absorbable, and can be locally applied to a particular tissue.

·       Depending on the size and density of the mesh, it can carry protein molecules between 14,000 and 1,50,000 Daltons.

 

REFERENCES:

1.      Bharskar GR, A review on hydrogel. World journal of Pharmacy and Pharmaceutical science. 2020; 9 (7):1288-1298.

2.      Nasitha A., Krishnakumar K., Hyrogel in Pharmaceuticals: a review, 2016; 3(3): 265-270.

3.      Das N., Preparation methods and properties of hydrogel: A review, International Journal of Pharmacy and Pharmaceutical Sciences, 2013; 5(3): 112–117.

4.      Hoare TR Kohane DS, Hydrogels in drug delivery: Progress and challenges, Polymer, 2008; 49(8): 1993–2007.

5.       Pal K, Banthia AK, and Majumdar DK, Preparation and characterization of polyvinyl alcohol-gelatin hydrogel membranes for biomedical applications, AAPS PharmSciTech, 2007; 8: 1.

6.      Hennink WE and Nostrum CF, Novel crosslinking methods to design hydrogels,‖ Advanced drug delivery reviews, 2002; 54(1): 13-36.

 

Received on 13.08.2022         Accepted on 21.10.2022        

Accepted on 14.11.2022         ©A&V Publications all right reserved