Excipients - Definitions

Acidifying agent

To make solutions acidic or adjusts pH. Produces sour taste

Alkalinizing agent

To make solutions alkaline or adjusts pH. Produces bitter taste

Adsorbent

Holds other molecules onto its surface by physical or chemical interactions

Air displacement

Displaces air in a hermetically sealed container to enhance product stability

Antifoaming agent

Breaks up the froth/foam and inhibits froth formation

Antifungal preservatives

Prevents the growth of fungi in liquid and semisolid preparations

Antimicrobial preservative

Prevents growth of microorganisms in liquid and semisolid preparations. May be bacteriostatic - do not kill, but prevent further bacterial growth

Antioxidant - water soluble

• Prevents degradation of water-soluble product by oxidation

• for aqueous preparations

antioxidant - oil-soluble 

• prevents degradation of oil-soluble products by oxidation and rancidification of oils or fats

• for oils and emulsions

Chelating agent

A substance that forms stable water-soluble complexes (chelates) w/ metals and makes metals unavailable to cat. degradation reactions (eg. oxidation or hydrolysis)

Clarifying agent

Filtering aid to remove oil droplets (flavor oils) present on the top of liquid orals through adsorption

Colorant

Imparts color

Emollient

Softens skin or soothes irritate skin or mucous membranes

Typically, fatty acids (oils and waxes)

Emulsifying agent (EA)

Promotes stabilization of small liquid droplets in non-compatible liquids. (o/w or w/o)

eg. milk proteins (EA) in milk - prevent fat droplets to join (coalescence) and keep them dispersed by forming a coat around the fat dropelts\

• gums

• colloids (extremely fine particles)

• surfactants

Enteric coating

Polymer coating on tablets/capsules that prevent meds from breaking down in stomach

Allows drug to release in intestine

Film coating

Polymer coating applied to tablets- protect dosage form from environment or prevent bad taste of drug or impart modified release patterns to formulation

Usually celluloses are good examples

Flavors

Gives pleasant odor to formulation

Volatile oils dissolved in oil, alcohol, or water

Flavoring or sweetening agent

Imparts pleasant flavor and sweetness to preparation

Foaming agent

Amphiphilic substances like surfactant (eg. soaps) that forms foam/froth upon shaking

Tweens/SLS

Foam adjuvant/ foam stabilizer

Surfactants that stabilize froth or foam

• used in foam-forming gels/lotions

Humectant

Prevents drying of preparations (ointments, creams, gummy bears) and adds moisture enhancer in topicals

Hydrophilic solvents - Co-solvents

Liquid w/ high miscibility w/ water used to dissolve poorly soluble drugs

Hydrophobic solvents

Liquid w/ low or no miscibility w/ water used to dissolve solutes 

Levigating agents

Liquid used as an intervening agent- reduce particle size of powder by grinding (mortar)

• opposite to its solubility

Ointment base

Semisolid vehicle for medicated ointments

Plasticizer

Component of film-coating solutions- makes films pliable, enhances the spread of coat over tablets, beads, and granules

Stiffening agent

Increases viscosity or hardness of preparation, usually an ointment or lip balm

High melting point fatty acids (waxes)

• for fatty acid-based ointments, suppositories, and lip-balms

Suppository base

Vehicle for suppositories

Surfactant - (surface-active agent)

Substances that translocate to surface or interfaces to reduce surface or interfacial tension

Commonly:

• wetting agents

• detergents

• emulsifying agents

• enhance spread of eye/ear drops

Sweetening agent

Gives sweetness to preparation

Tablet anti-adherent

Prevents tablet ingredients from sticking to punches and dies during production

Tablet binder

Substances that cause adhesion of powder particles to hold them together in tablet granulations

Diluent or Filler (tablets/capsules)

Inert filler that creates desired bulk, flow properties, and compression characteristics of tablets and capsules

Disintegrant (tablets/capsules)

Promotes disruption of tablets or large solid mass of other formulations into smaller particles that are more easily dispersed or dissolved

Glidant

Improves flow properties of powder mixture in tablet and capsule formulations

Tablet lubricant

Reduces friction of tablet formulations during tablet compression

Tablet/capsule opaquant

• makes colors opaque

Renders coating opaque when used alone or w/ a colorant

Tablet polishing agent

Gives attractive sheen to coated tablets

Tonicity agent

Adjusts isotonicity of parenteral similar to physiological tonicity 

Vehicle

Base used in variety of liquids (oral/parenteral) to make up final vol. Oral liquids are aq or hydroalcoholic

similar to diluent in solid dosage forms or base in ointments

Viscosity enhancers

Increases viscosity of a liquid or semisolid. Gums or Cellulose-based polymers

Used as:

• suspending agent in suspensions

• increase contact time in ophthalmic solutions

• increase thickness of gel or ointment

Wetting/solubilizing agent

Reduces surface tension, helps spreading water or wetting w/ water. Helps in fat dissolution