12936_CH08.qxd 8/31/08 7:42 AM Page 123 Chapter 8 The Right Dosage Form and the Right Route of Administration: Working With Accuracy KEY TERMS • alcoholic solution OBJECTIVES • angina • anhydrous After completing this chapter, the student will be able to: absorption bases • Describe the various dosage forms available for • aseptic technique medications. • binders • bioavailability • Define the routes of administration for medications. • bolus dose • Correlate the dosage forms with the appropriate route of • buccal tablets administration. • compressed tablets • Apply the dosage form and administration route to • continuous prescription evaluation. infusion • controlled-release • Utilize appropriate reference books to verify prescription tablets information. • diluents • disintegrates • Adapt the dosage form and administration route for • effervescent special-needs patients. tablets • elixirs • enteric-coated tablets 123 12936_CH08.qxd 8/31/08 7:42 AM Page 124 124 Standards of Practice for the Pharmacy Technician • excipients • intracardiac • orally disintegrating • fast-dissolving tablets administration tablets • film-coated tablets • intradermal injection • parenteral • glycerite • intramuscular (IM) • percutaneous administration absorption • granules • intraperitoneal • stability • hydroalcoholic solution administration • subcutaneous (SQ) • hydrocarbon bases • intrapleural administration • hydrophobic administration • sublingual tablets • implant • intravenous (IV) • tincture • inhalation administration • transdermal route of • intra-arterial • lubricants administration administration • occlusive • vehicle • intra-articular • oleaginous • viscous aqueous administration solutions Medication can be administered in a variety of forms to accommodate the special diluents Usually inert needs of the patient, to facilitate delivery to the indicated site, or to control the rate powders added to a drug to of absorption. The available dosage form will determine the route of administra- increase the volume. tion, although some dosage forms can be administered by more than one route. An binders Materials added to important aspect of the prescription evaluation process performed by the technician a tablet formulation to hold involves matching the dosage form ordered with the route of administration pre- the powders together. scribed in the directions to the patient. Any discrepancy should be verified before lubricants Topical the prescription is entered into the patient profile. compounds that are intended to sooth and moisturize dry irritated skin. Solid Oral Dosage Forms disintegrates Compounds added to a tablet formulation Tablets to ensure that the tablet will One of the oldest and most common dosage forms is the oral tablet. The tablet is a break apart and be available solid dosage form that contains an active ingredient (the drug) and may or may not for absorption into the system. have additional diluents, binders, lubricants, colorings, flavorings, and/or disinte- compressed tablets grates. Most commercial tablets on the market today are compressed tablets formed Tablets that are produced by a by using pressure and some type of punch machine to create the desired size and tablet press exerting great shape. Compressed tablets may be sugar-coated and the coatings may be flavored pressure on powders, and and colored (see Fig. 8.1). This coating process has little therapeutic effect but shaped by punches and dies of increases patient acceptance and creates a pharmaceutically elegant tablet. Film- various sizes. coated tablets are similar in appearance to sugar-coated tablets but the film is a thin film-coated tablets layer of water-soluble material. See Figure 8.2 for an example of a film-coated Tablets covered with a thin tablet. Enteric-coated tablets are useful for drugs that may be irritating to the layer of polymer designed to mucosa of the stomach or will be inactivated by the gastric fluid in the stomach. dissolve at the desired place The coating is formulated to resist dissolving in the stomach but will disintegrate in in the gastrointestinal tract. enteric-coated tablets Tablets formulated to pass Figure 8.2 Compressed tablets through the stomach un- may be coated with a thin layer changed and dissolve in the Figure 8.1 The most common of water-soluble material to form intestine. tablet form is the compressed tablet. a film-coated tablet. 12936_CH08.qxd 8/31/08 7:42 AM Page 125 CHAPTER 8 The Right Dosage Form and the Right Route of Administration: Working With Accuracy 125 Figure 8.3 Enteric-coated tablets are coated with a substance that will resist dissolving in the stomach but Figure 8.4 Controlled-release will readily dissolve in the tablets release the drug over a intestine. period of time. the intestine. Figure 8.3 shows an example of an enteric-coated tablet. Controlled- controlled-release tablets release tablets are formulated to release the drug over a predetermined period of Tablets that have been formu- time to provide more constant levels of the drug in the bloodstream (see Fig. 8.4 for lated to release a drug slowly a controlled-release tablet). This may be accomplished in several ways. The drug over a predetermined period may be encapsulated into beads or granules of various sizes and thicknesses to of time. dissolve at different times. The tablet may have two or more layers formulated to granules Powders that have release the drug at different times. The drug may be embedded in an inert wax been wetted and broken into matrix that allows the drug to leach out through a small hole. With this type of tablet coarse particles to increase the wax coating may be eliminated in the feces of the patient, causing him or her to stability. think the drug did not have any effect. The patient may need reassurance that the effervescent tablets drug was released and exerted the proper therapeutic effect. Effervescent tablets Tablets that are compounded combine the drug with sodium bicarbonate and an acid so that when water is added with an effervescent salt that the tablet will disintegrate, releasing bubbles of carbon dioxide and forming an ef- releases a gas when placed in fervescent solution. An effervescent tablet is pictured in Figure 8.5. Buccal tablets water, causing the medication are small, flat tablets that are placed between the lip or cheek and gum, and dissolve to dissolve rapidly. slowly into the oral mucosa. Sublingual tablets are similarly formulated to dissolve buccal tablets Tablets and be rapidly absorbed through the oral mucosa, but are placed under the tongue. designed to be placed in the Orally disintegrating tablets are manufactured by means of numerous technologies cheek so that the drug can be to formulate a powder into a tablet that will quickly dissolve when placed in the absorbed through the oral mouth. This dosage form originated to prevent psychiatric patients from storing mucosa. tablets in a pouch in the cheek (a process known as “cheeking”) and removing them sublingual tablets Small, after the nurse leaves the room. This would interfere with their medication therapy. fast-dissolving tablets that are A number of products have emerged from the use of this technology to create a con- administered under the tongue venient tablet that does not require water to facilitate swallowing. Figure 8.6 shows and absorbed through the oral an orally disintegrating tablet. mucosa. excipients Ingredients Tablet Ingredients added to a drug in a solid Because most tablets on the market today are compressed tablets produced by com- dosage form to create an pression with a punch and die machine, the ingredients added to the drug are impor- acceptable tablet or capsule. tant for producing a uniform tablet that has the correct amount of hardness, will not stability The amount of stick to the machine, and will disintegrate and dissolve in the correct amount of time time a drug or compound to release the drug for absorption into the system. These added ingredients are called retains its stated potency. excipients; they are considered to be inert, but research has shown that they do affect bioavailability The ability the stability and bioavailability of the dosage form. It is important for the technician of a drug to exert its therapeu- to be aware of the excipients used because they may vary when a brand-name drug tic effect on the body. Figure 8.5 Effervescent tablets have sodium bicarbon- ate and an acid added to the drug so that when they are Figure 8.6 Orally disintegrating placed in water they form a tablets will dissolve quickly when bubbling solution. placed in the mouth. 12936_CH08.qxd 8/31/08 7:42 AM Page 126 126 Standards of Practice for the Pharmacy Technician is reformulated as a generic. The generic version of the drug is required to have the same amount of active ingredient as the brand-name product and demonstrate equal bioavailability, but a change in one or more excipients could cause an allergic reac- tion in a patient or cause the drug to act differently in a given individual. When the single dose of an active ingredient is small, such as 1 mg, a diluent must be added to improve accuracy in the dose and to make a tablet of a reason- able size. Sometimes the diluent can impart other properties to the tablet, such as increasing the rate of disintegration to make the tablet acceptable for a chewable dosage form. Binders are used to increase the cohesiveness of the powders so that the tablet will not crumble during or after compression. Care must be taken to use the proper amount of binder so that the finished tablet will not be so hard that dissolution will be affected. lubricants Topical Lubricants are added to prevent the tablet from sticking to the machine and compounds that are intended affecting the appearance and strength of the dosage form. Disintegrants are to sooth and moisturize dry added to the tablet formulation to ensure that the tablet will break up and release irritated skin. the active ingredient in a reasonable amount of time so that it may be absorbed disintegrants Compounds into the system.