Excipients by function

In addition to the different origins and roles for the formulation of a drug product excipients can differentiated by their function. The major groups of excipients by function are:

Anti-Foaming Agents / Defoamer
Antioxidants
Binders
Coatings
Colorants / Colors
Disintegrants
Emulsifiers / Surfactants
Excipients for Ointments
Excipients for Suppositories
Fillers & Diluents
Flavoring Agents / Flavors
Gelling Agents
Lubricants & Glidants
Plasticizers
Preservatives
Solvents
Suspension & Viscosity Agents
Sweetener
Etc.

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Anti-foaming Agents / Defoamer

A defoamer or an anti-foaming agent is a chemical additive that reduces and hinders the formation of foam in pharmaceutical process or bioprocesses. The terms anti-foam agent and defoamer are often used interchangeably.

Commonly used agents are insoluble oils, polydimethylsiloxanes and other silicones, certain alcohols, stearates and glycols. The additive is used to prevent formation of foam or is added to break a foam already formed.

Antioxidant Excipients

Antioxidant excipients prevent, delay or minimize the oxidation of foods, pharmaceuticals or nutraceuticals to which they are added with the aim of achieve a better and longer stability of the product.

Binder Excipients

Binders hold the ingredients in a tablet / granule together. Binders ensure that tablets and granules can be formed with required mechanical strength, and give volume to low active dose tablets.

A binder is a substance capable of sticking (interacting) with two substances, forming a bridge between both (+ form a network of molecules stabilizing the glued system)

Coating Excipients

A wide variety of pharmaceutical products, including pellets, granules, capsules, powders, and crystals are often film coated. In this present article, we will concentrate on the film-coating of tablets.

The procedure of coating tablets is a complex process that results in the forming of a thin layer around the tablet. This layer is in the range of 20 to 200 μm in thickness, or around 1 to 9% of the initial weight of the tablet. As a reference, a human hair is usually around 100 μm thick, much like the typical thickness of an immediate release coating.

Disintegrant Excipients

Disintegrants and superdisintegrant excipients are essential components used in the pharmaceutical industry to enhance the dissolution and bioavailability of active pharmaceutical ingredients (APIs). These excipients facilitate the disintegration and rapid breakup of tablets or capsules, which ultimately increases their rate of absorption in the body.

Flavor Excipients

According to David Tisi to a sensory scientist, the term “flavor” refers to the combination of taste, aroma, mouthfeel and texture. To a formulator, a flavor is a commercial ingredient that is a blend of volatile chemicals responsible for imparting the aroma of a product – orange, chocolate, mint. In addition to aroma chemicals flavors contain bulking agents (carriers) and other functional ingredients such as preservatives, suspending agents and emulsifiers.

Glidant & Lubricant Excipients

Glidants are added to improve the flowability of the powder mixture during tablet manufacturing. Powders can be sticky, cohesive, and prone to forming clumps, which makes them difficult to handle in large-scale production. Glidants reduce the inter-particle friction, allowing the powder to flow more easily and uniformly into tablet presses or capsule filling machines.

Lubricants are used to reduce friction between the tablet or capsule and the equipment (e.g., tablet punches and dies, capsule filling machines) during the compression and ejection processes. This is essential to prevent the tablet or capsule from sticking to the equipment, which can lead to defects such as capping, breaking, or chipping of tablets.