Binder is one of an important excipient to be added in tablet formulation. In simpler words, binders or adhesives are the substances that promotes cohesiveness. It is utilized for converting powder into granules through a process known as Granulation. Granulation is the unit operation by which small powdery particles are agglomerated into larger entities called granules.

Types of Binders 

Classification of Binders

SugarasNatural BindersSynthetic/Semisybthetic Polymer
Sucrose Acacia Methyl Cellulose
Liquid glucose Tragacanth Ethyl Cellulose

Gelatin Hydroxy Propyl Methyl Cellulose ( HPMC)

Starch Paste Hydroxy Propyl Cellulose

Pregelatinized Starch Sodium Carboxy Methyl Cellulose

Alginic Acid Polyvinyl Pyrrolidone (PVP)

Cellulose Polyethylene Glycol (PEG)


Polyvinyl Alcohols


Polymethacrylates



Characteristics of Commonly Used Binder

BINDER SPECIFIED
CONCENTRATION
COMMENTS
Starch Paste 5-25%w/w - Freshly prepared starch paste is used as a binder.

Pregelatinized Starch 

(PGS)
[Partially and Fully PGS

5-10%w/w
(Direct Compression)

5-75%w/w
(Wet Granulation )

- It is starch that have been processed chemically and/or mechanically to ruptureall or part of the granules in the presence of water and subsequently dried.
- It contains 5% free amylose, 15% free amylopectin and 80% unmodified starch.
- used as tablet binder, diluent, disintegrant and flow aid.
- They enhance both flow and compressibility and
can be used as binders in Direct Compression as
well as Wet Granulation.
- High purity PGS allow simplified processing as they swell in cold water and therefore reduce time/costs compared with traditional starch paste
preparation.
Hydroxypropyl Methyl Cellulose (HPMC) 2-5%w/w
- Comparable to Methyl Cellulose.
- Used as a binder in either wet or dry granulation processes.
Polyvinyl Pyrrolidone (PVP) 0.5-5%w/w
- Soluble in both water and alcohol.
- Used in wet granulation process.
- added to powder blends in the dry form and granulated in situ by the addition of water, alcohol or hydroalcoholic solution.
- Binder for chewable tablets.
- The drug release is not altered on storage.
Polyethylene Glycol (PEG) 6000 10-15%w/w
-          Used as a meltable binder.
-          Anhydrous granulating agent where water or alcohol cannot be used .
-          It may prolong disintegration time when concentration is 5% or higher
  - It improves the plasticity of other binders.

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