Tablet Excipients and their functionalities

Sponsored Links

Tablet Excipients

1.5.1 Excipient and their functionalities (13-15)

Excipient means any component other than the active pharmaceutical ingredient(s) intentionally added to the formulation of a dosage form. Many guidelines exist to aid in selection of non toxic excipients such as IIG (Inactive Ingredient Guide), GRAS (Generally Regarded As Safe), Handbook of Pharmaceutical Excipients and others.

While selecting excipients for any formulation following things should be considered wherever possible: keep the excipients to a minimum in number minimize the quantity of each excipients and multifunctional excipients may be given preference over unifunctional excipients.

Excipients play a crucial role in design of the delivery system, determining its quality and performance. Excipients though usually regarded as nontoxic there are examples of known excipient induced toxicities which include renal failure and death from diethylene glycol, osmotic diarrhoea caused by ingested mannitol, hypersensitivity reactions from lanolin and cardiotoxicity induced by propylene glycol.

Excipients are chosen in tablet formulation to perform a variety of functions like

i) For providing essential manufacturing technology functions (binders, glidants, lubricants may be added),

ii) For enhancing patient acceptance (flavors, colourants may be added),

iii) For providing aid in product identification (colourants may be added),

iv) For Optimizing or modifying drug release (disintegrants, hydrophilic polymers, wetting agents, biodegradable polymers may be added),

v) For enhancing stability (antioxidant, UV absorbers may be added)

Various excipients used in tablet formulation and their functionalities. (1, 4, 16)

Table.2. Excipient With Their Functions In Tablet Formulation

EXCIPIENT

FUNCTION

Diluents or Fillers

Diluents make the required bulk of the tablet when the drug dosage itself is inadequate to produce tablets of adequate weight and size.

Binders or Granulating agents or Adhesives

Binders are added to tablet formulations to add cohesiveness to powders, thus providing the necessary bonding to form granules, which under compaction form a cohesive mass or a compact which is referred to as a tablet.

Disintegrants

A disintegrant is added to most tablet formulations to facilitate a breakup or disintegration of the tablet when placed in an aqueous environment.

Antifrictional Agents

Lubricants

Lubricants are intended to reduce the friction during tablet formation in a die and also during ejection from die cavity.

Antiadherents

Antiadherents are added to reduce sticking or adhesion of any of the tablet granulation or powder to the faces of the punches or to the die wall.

Glidants

Glidants are intended to promote the flow of tablet granulation or powder mixture from hopper to the die cavity by reducing friction between the particles.

MISCELLANEOUS

Wetting agents

Wetting agents are added to tablet formulation to aid water uptake during disintegration and assist drug dissolution.

Dissolution retardants

Dissolution retardants as the name suggest, retards the dissolution of active pharmaceutical ingredient(s).

Dissolution enhancers

Dissolution enhancers as the name suggest, enhance the dissolution rate of active pharmaceutical ingredient(s).

Adsorbents

Adsorbents are capable of retaining large quantities of liquids without becoming wet; this property of absorbent allows many oils, fluid extracts and eutectic melts to be incorporated into tablets.

Buffers

Buffers are added to provide suitable micro environmental pH to get improved stability and / or bioavailability.

Antioxidants

Antioxidants are added to maintain product stability, they act by being preferentially oxidized and gradually consumed over shelf life of the product.

Chelating agents

Chelating agents are added to protect against autoxidation; they act by forming complexes with the heavy metal ions which are often required to initiate oxidative reactions.

Preservatives

Preservatives are added to tablet formulation in order to prevent the growth of micro-organisms.

Colours

Colours are added to tablet formulation for following purposes: to disguise off colour drugs, product identification and for production of more elegant product.

Flavours

Flavours are added to tablet formulation in order to make them palatable enough in case of chewable tablet by improving the taste.

Sweeteners

Sweeteners are added to tablet formulation to improve the taste of chewable tablets.

O Key Phrases

O Tablet formulations are usually designed to satisfy following criteria- Patient acceptability; accuracy and uniformity of drug content; manufacturability; optimal drug dissolution and stability.

O Excipients are any component other than active pharmaceutical ingredient(s) intentionally added to the formulation of a dosage form.

O Excipients play a crucial role in design of the delivery system, determining its quality and performance.

O Various excipients used in tablet formulation are diluents, binders, disintegrants, lubricants, antiadherents, glidants, wetting agents, dissolution retardants, dissolution enhancers, absorbents, buffers, antioxidants, chelating agents, preservatives, colours, flavours, sweeteners, etc.

About the Author

Dr.Mukesh Gohel's picture
Author: Dr.Mukesh Gohel

Dr. Mukesh Gohel is principal, professor at the LMCP, Ahmedabad served in academics for more than 40 years. He provides training in leading pharmaceutical industries in the areas of Design of Experiments and Quality by Design. His current areas of interest are direct compression and improvement of drug dissolution.

You May Also Like..