Category: Pharmaceutical Excipient Types

Surfactants (surface active agent) are substances that absorb to surfaces or interfaces to reduce surface or interfacial tension. May be used as wetting agents, detergents, or emulsifying agents. Examples Benzalkonium

Suspending agent are viscosity-increasing agent used to reduce sedimentation rate of particles in a vehicle in which they are not soluble; suspension may be formulated for oral, parenteral, ophthalmic, topical, or other route.

Stiffening agent is used to increase thickness or hardness of a preparation, usually an ointment. Examples Cetyl alcohol Cetyl esters wax

Solvent is used to dissolve another substance in preparation of a solution; may be aqueous or not (e.g., oleaginous). Cosolvents, such as water and alcohol (hydroalcoholic) and water and glycerin, may be used when needed. Sterile solvents are used in certain preparations (e.g., injections). Examples Alcohol

Plasticizer is a component of film-coating solutions to make film more pliable, enhance spread of coat over tablets, beads, and granules. Examples • Diethyl phthalate • Glycerin

Ointment base is semisolid vehicle for medicated ointments. Examples Lanolin Hydrophilic ointment Polyethylene glycol ointment Petrolatum Hydrophilic petrolatum

Levigating agent liquid is used as an intervening agent to reduce the particle size of a powder by grinding, usually in a mortar. Examples • Mineral oil • Glycerin • Propylene glycol

Humectant is used to prevent drying of preparations, particularly ointments and creams. Examples Glycerin Propylene glycol Sorbitol

Flavorant is used to impart a pleasant flavor and often odor to a preparation. In addition to the natural flavorants  listed, many synthetic ones are used. Examples Anise oil Cinnamon oil Cocoa

Encapsulating agent is used to form thin shells to enclose a drug for ease of administration. Examples • Gelatin

Emulsifying agent is used to promote and maintain dispersion of finely  subdivided particles of liquid in a vehicle in which it  is immiscible. End product may be a liquid emulsion  or semisolid emulsion (e.g., a cream). Examples Acacia Cetomacrogol

Clarifying agent is used as a filtering aid for its adsorbent qualities. Examples Bentonite

Colorant is used to impart color to liquid and solid (e.g., tablets and capsules) preparations. Examples FD&C Red No. 3 FD&C Red No. 20 FD&C Yellow No. 6 FD&C Blue No. 2

Buffering agent is used to resist change in pH upon dilution or addition of acid or alkali. Examples Potassium metaphosphate Potassium phosphate,monobasic Sodium acetate

Chelating agent is substance that forms stable water-soluble complexes (chelates) with metals; used in some liquid pharmaceuticals as stabilizers to complex heavy metals that might promote instability. In such use, they are also called sequestering agents Examples Edetic acid