Glossary of Pharmaceutical Dosage Forms and Drug Delivery Systems

Pastes

Pastes are semisolid preparations that contain one or more drug substances intended for topical application to the skin. Generally, pastes contain a higher proportion of solid components than do ointments and thus are stiffer, less greasy, and more absorptive of serous secretions.

Pastille

Pastilles are tasty solid oral preparation consisting of one or more medicaments in an inert base and intended to dissolve slowly in the mouth.

Pessary

Pessaries are solid, single-dose preparations intended for insertion into the vagina for local treatment. Pessaries can be prepared in various shapes, usually ovoid, with a volume and consistency suitable for insertion into the vagina. They contain one or more active substances dissolved or dispersed in a suitable base that may be soluble or dispersible in water, or may melt at body temperature. Additionally, they may contain diluents, adsorbents, surfactants, lubricants, antimicrobial preservatives, coloring matter, and other stabilizers if necessary.

Pill

Pills are solid dosage form consisting of one or more medicaments incorporated in a spherical or ovoid mass.

Plasters

Plasters are solid or semisolid masses spread across a suitable backing material and intended to provide protection and prolonged contact with the skin. They may provide an occlusive and macerating action and bring medication into close contact with the surface of the skin.

Poultice

Poultices are soft, viscous, paste-like preparation intended for application to the skin while hot. The poultice must retain heat for a considerable time because it is intended to supply warmth to inflamed parts of body, e.g., Kaolin poultice (BPC).

Powders

Powders are dry mixtures of finely divided medicinal and inactive ingredients that are intended for internal or external use. Powders may be dispensed in bulk form, or they may be divided into single-dosage units and packaged in folded papers or unit-of-use envelopes. They are dissolved in water prior to ingestion when used internally.

Premixes

Premixes are mixtures of one or more drug substances with suitable vehicles intended for admixture to animal feedstuffs before administration. They are generally in powdered, pelletized, or granulated form.

Solutions

Solutions are liquid preparations that contain one or more chemical substances (solutes) dissolved in a solvent or mixture of mutually miscible solvents. Depending on their intended use, solutions may be classified as oral, topical, ophthalmic, otic, nasal, rectal, urethral, or parenteral. Other solutions, because of their composition or use, may be classified as other dosage forms. For example, syrups (aqueous solutions containing sugar; even though some syrups may contain some alcohol), elixirs (sweetened hydroalcoholic solutions), tinctures, or fluidextracts (solutions prepared by extracting active constituents from crude drugs), etc.

Spirits

Spirits are alcoholic or hydroalcoholic solutions of volatile substances prepared usually by simple solution or by admixture of the ingredients. Depending on their contents, some spirits are used orally for medicinal purposes and others as flavoring agents.

Suppositories

Suppositories are solid dosage forms in which one or more drug substances are dispersed in a suitable base and molded or otherwise formed into a suitable shape for insertion into body cavities (usually rectal but also vaginal and urethral) where they either soften, melt, or dissolve, releasing the drug. While suppositories are frequently used for local action, they can also be used to achieve adequate systemic concentration of a drug. Suppositories are of various weights, sizes, and shapes, depending on their intended use.

Suspensions

Pharmaceutical suspensions are liquid preparations containing finely divided drug particles dispersed throughout a liquid phase in which the drug particles are not readily soluble. In an ideal suspension, particles are uniformly dispersed, free from aggregation. Even if sedimentation occurs, particles should be resuspended upon mild agitation.

Suspension dosage form is used for providing a liquid dosage form for insoluble drugs. Also, it is an ideal dosage form for drugs that are unstable in an aqueous medium for extended periods of time. Such drugs are most frequently supplied as dry powder for reconstitution at the time of dispensing.

Read More on Pharmaceutical Suspensions, Types, Manufacturing Processes, and Quality Control

Syrups

Syrups are solutions containing a high concentration of sucrose or other sugars with or without flavoring agents and medicinal substances. Syrups may be medicated or nonmedicated. The nonmedicated often referred to as simple syrups are used as vehicles for medicinal substances to be added later, either in the extemporaneous compounding of prescriptions or in the preparation of a standard formula for a medicated syrup (a syrup containing a therapeutic agent).

Syrups provide a pleasant means of administering a liquid form of a disagreeable-tasting drug. In addition to the sugar or sweetener, syrups also contain cosolvents, flavorants, colorants, and antimicrobial preservatives. Syrups may also contain solubilizing agents, thickeners, or stabilizers.

Tablets

Tablets are solid dosage forms containing drug substances usually prepared with the aid of suitable pharmaceutical excipients. The excipients include diluents, disintegrants, colorants, binders, solubilizers, glidants, flavorant etc.

Tablets may vary in shape, size, weight, hardness, thickness, disintegration, and dissolution characteristics and in other aspects, depending on their intended use and method of manufacture. Most tablets are intended to be swallowed whole. However, some are prepared to be chewed (chewable tablets), others to be dissolved in the mouth (buccal tablets) or under the tongue (sublingual tablets), and still others to be dissolved in water before taking (effervescent tablets).

A tablet that is shaped like a capsule but smooth-sided like a tablet is called a caplet.

Read More on Tablet Dosage Forms, General Properties, Types, Manufacturing Processes, and Quality Control

Tinctures

Tinctures are alcoholic or hydroalcoholic solutions that contain either pure chemical substances or plant extracts. Most chemical tinctures are applied topically (e.g., iodine tincture). Plant extractives are used for their content of active pharmacologic agents. Because of the alcoholic content, tinctures must be tightly stoppered and not exposed to excessive temperatures to avoid or minimize the evaporation of alcohol.

References

• Allen, L. and Ansel, H. (2014). Ansel’s Pharmaceutical Dosage Forms and Drug Delivery Systems (10^th ed.). Philadelphia, Lippincott Williams & Wilkins.
• H. (2010). Pharmaceutical Calculations. Philadelphia: Wolters Kluwer Health Lippincott Williams & Wilkins.
• Aulton, M. and Taylor, K. (2013). Aulton’s Pharmaceutics: The Design and Manufacture of Medicines, (4^th ed.). Edinburgh: Churchill Livingstone.

• Dash, A., Singh, S. and Tolman, J. (2014). Pharmaceutics: Basic Principles and Application to Pharmacy Practice. USA: Elsevier Inc.

• Gad, S. (2008). Pharmaceutical Manufacturing Handbook: Production and Processes. New Jersey: John Wiley & Sons, Inc.
• Mahato, R. and Narang, A. (2018). Pharmaceutical Dosage Forms and Drug Delivery (3^rd ed.). New York: Taylor & Francis Group, LLC.
• Marriott, J., Wilson, K., Langley, C., and Belcher, D. (2010). Pharmaceutical Compounding and Dispensing (2^nd ed.). UK: Pharmaceutical Press.