Routes of Drug Administration and Dosage Formulations Routes

Routes of Drug Administration and Dosage Formulations

Routes of administration

Chapter Topics • • Routes of administration Oral route of administration Transmucosal route of administration Topical route of administration Inhalation route of administration Parenteral route of administration Drug delivery systems

Learning Objectives • Differentiate between the terms route of administration, dosage form, and drug delivery system. • Explain the qualities of oral, topical, and parenteral dosage forms. • Identify inactive ingredients and various coatings of tablets. • Differentiate between a suspension and an emulsion. • Identify dosage formulations utilizing the transmucosal route of administration. • Define the emulsion characteristics of topical products. • Explain the advantages and disadvantages of oral, topical, and parenteral dosage formulations.

Learning Objectives (continued) • Discuss the importance of syringe selection for a diabetic patient. • Contrast the advantages and disadvantages of insulin in multi-dose vials and prefilled insulin syringes. • Understand the stability and expiration dates of insulin at room temperature and refrigerated temperatures. • Demonstrate correct techniques for administration of eyedrops, eardrops, metered-dose inhalers, and various parenteral injections. • Differentiate among enteric-coated, sustained-release, and extended-release dosage formulations.

Routes of Administration • Route of administration – A way to get a drug into or onto the body – Oral, transmucosal, topical, inhalation, parenteral • Dosage form – The physical manifestation of a drug that is designed to deliver the medication – Tablet, capsule, suspension, ointment, cream

Oral Dosage Forms • Tablets Although tablets and capsules may have distinctive markings and colors, the pharmacy technician should rely on the National Drug Code (NDC) number–not the appearance of the medication–to confirm the medication’s identity. – Solid dosage form produced by compression – Contains one or more active ingredients along with inactive ingredients called excipients – Types of tablets • • • Compression tablet Multiple compression tablet Caplet Chewable tablet Oral disintegrating tablet (ODT)

Oral Dosage Forms (continued) Inert Tablet Ingredients and Their Uses

Oral Dosage Forms (continued) • Tablet coatings – Sugar-coated tablet (SCT) • Layer of sugar protects the medication and improves appearance and flavor • Can be crushed but loses its taste-masking effects – Film-coated tablet (FCT) • Layer of polymer that may be either soluble or insoluble in water • Some prevent serious GI effects • Can be crushed but loses its taste-masking effects The oral route is not appropriate for patients who are experiencing nausea or vomiting.

Oral Dosage Forms (continued) • Capsules – Active ingredient in the form of a granular powder or liquid gel enclosed by gelatin shell • Powders – Active ingredient in the form of fine particles • Effervescent salts – Granules or coarse powders containing active ingredient plus sodium bicarbonate combination – Fizz when dissolved in water

Oral Dosage Forms (continued) • Solutions – Active ingredients are completely dissolved in a liquid – Elixir • Clear, sweetened, flavored solution containing water and ethanol – Syrup • An aqueous solution thickened with a large amount of sugar • Preferred vehicle for pediatric medications Because of their high sugar content, syrups should be used cautiously with diabetic patients.

Oral Dosage Forms (continued) Suspension Emulsion Solid particles of active A mixture of two immiscible ingredients mixed with, but substances not dissolved in, liquid Considered a dispersion Contains an emulsifying agent that stabilizes it An incomplete mixture of solid and liquid An incomplete mixture of two liquids

Oral Dosage Forms (continued) • Colloid – A mixture having physical properties between those of a solution and a fine suspension • Magma–has ultrafine particles • Microemulsion–one liquid dispersed in another, clear because of the fine size of the dispersed droplets

Oral Dosage Forms (continued) Dosage form Advantages Disadvantages Tablets Low cost, precise dosing, increased palatability, dose can be manipulated if scored Delayed onset of action, destruction of drug by GI fluids, local GI side effects, delayed absorption of food in stomach, ineffective for patients unable to swallow Delayed-release (DR) tablets Longer duration of action, fewer side effects, reduced dosing schedule Cannot be split or crushed, slower onset of action, prolonged side effects, more expensive Capsules Easier to swallow, more rapid dissolution, faster onset of action, contents of some can be sprinkled over food or mixed with water Dose cannot be manipulated Liquids Faster onset of action, easy administration, individualized dosing Less stable, sugar content a problem for diabetic patients, unpleasant taste

Oral Dosage Forms (continued) • Dispensing and administration pearls – Delayed-release and enteric-coated tablets should not be crushed. – Some capsules may be opened up and sprinkled on food. – Expiration of most antibiotic suspensions is 7 to 10 days at room temperature, 14 days in the refrigerator. – Suspensions should be shaken well. – Oral syringes, medications cups, or droppers should be used to measure liquid medications.

In the Know: True or False • A solubilizer promotes adhesion of the materials in a tablet. false • The pharmacy technician should rely on the appearance of a tablet to confirm its identity. false • In a suspension, solid particles of active ingredients are mixed with but not dissolved in liquid. true

Transmucosal Dosage Forms • Allows drug to be absorbed through the permeable mucous membranes of the mouth, eyes, ears, nose, rectum, vagina, or urethra • Sublingual medications – Tablet placed under the tongue where it is rapidly absorbed by blood vessels – Example: nitroglycerin tablets Sublingual nitroglycerin tablets are sensitive to air and light and, consequently, will lose potency over a certain period. These tablets should be kept in their original container and replaced every 6 months.

Transmucosal Dosage Forms (continued) • Buccal medications Absorbed by blood vessels in the lining of the mouth Examples: sore throat lozenges, nicotine gum If nicotine gum is chewed vigorously, too much nicotine can be released, causing unpleasant side effects. Therefore, pharmacy personnel should instruct patients on the proper chewing technique for nicotine gum.

Transmucosal Dosage Forms (continued) • Ophthalmics – Sterile solutions, suspensions, or ointments administered to one or both eyes

Transmucosal Dosage Forms (continued) • Ophthalmics – Multiple-dose products must contain a preservative. – Unit-of-use packages do not require a preservative. Unused ophthalmic medication should be discarded 30 days after the container is opened. Manufacturer expirations do not apply once a patient has opened the medication.

Transmucosal Dosage Forms (continued) • Otics – Nonsterile solutions or suspensions administered into one or both ears

Transmucosal Dosage Forms (continued) • Nasal sprays/solutions – Administered to the passages of the nasal cavity – Spray emits a fine dispersion of liquid

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Transmucosal Dosage Forms (continued) • Suppositories and solutions – A semisolid dosage form that melts at body temperature and releases an active drug Pharmacy personnel should remind patients who are using suppositories to remove the foil packaging prior to insertion. Some suppository ingredients, such as phenylephrine (used to shrink hemorrhoids) must be used with caution in patients with hypertension and other diseases. Refer patients to pharmacist to assist in product selection.

Transmucosal Dosage Forms (continued) • Suppositories and solutions (continued) Rectal suppositories, solution, enemas • May be used locally for cleansing the bowel, for laxative action, for hemorrhoids, or for colon disease • May be used systemically • Used sometimes if patients cannot take medications by mouth Refrigeration is necessary to store most rectal suppository medications.

Transmucosal Dosage Forms (continued) • Suppositories and solutions – Vaginal suppositories and solutions • Used for local effect such as cleansing, contraception, hormone replacement therapy, or treatment of infections – Urethral suppositories and solutions • Used for cancer treatment, incontinence, or impotence in men

Transmucosal Dosage Forms (continued) Dosage form Advantages Disadvantages Sublingual Rapid onset of action Short duration of action Buccal Rapid onset of action, fewer side effects Unpleasant taste, local mouth irritation, “dose dumping” if directions not followed Ophthalmics, otics, Fast onset of action, localized and nasal therapeutic effect sprays/solutions Nasal solutions/sprays Some have less systemic side effects than oral form Some have systemic side effects Suppositories and solutions Depending on the medication, can be used for either local or systemic action Patient inconvenience and discomfort, premature expulsion of the suppository, irregular drug absorption

Transmucosal Dosage Forms (continued) • Dispensing and administration pearls – A transmucosal fentayl citrate (OTFC) lollipop should be sucked for about 15 minutes. – Some ophthalmics require refrigeration but should be warmed to room temperature when given. – When giving antibiotic opththalmics, the tube or dropper should not touch the infected area. – Patients should be warned not to used OTC nasal decongestants for more than three days. – Lubrication of a rectal suppository with petroleum jelly should ease its administration.

In the Know: Fill in the Blank • Sublingual medications are placed under the patient’s _____. tongue • Eyedrops and ointment should be applied to the ______. conjunctival sac • Dose dumping if directions not followed may occur with _____ medications. buccal

Topical Dosage Forms • Used to apply a drug directly to the surface of the skin • Ointments, pastes, and plasters – Ointments • Water-in-oil (W/O) emulsion: contains a small amount of water dispersed in oil • Usually have an oily feel

Topical Dosage Forms (continued) • Ointments, pastes, and plasters – Pastes • Contains more solid materials than an ointment, has a dense consistency – Plasters • A solid or semisolid that adheres to the body and contains a backing material

Topical Dosage Forms (continued) • Creams, lotions, and gels – Creams • Oil-in-water (O/W) emulsion - contains a small amount of oil dispersed in water • Become invisible once applied to the skin – Lotions • Easily absorbed and can cover large areas of the body – Gels • Contain fine or ultrafine particles in a liquid • Apply evenly and leave a dry coat of the medication in contact with the area

Topical Dosage Forms (continued) Dosage form Advantages Topical Fast onset of action, few formulations , in systemic side effects general Disadvantages Some absorbed systemically, risk of local hypersensitivity Ointments Maintain moisture (good for Appearance, greasy residue dry areas of skin), longer contact time with skin Creams, lotions, gels Apply smoothly to the skin, more readily absorbed, more cosmetically acceptable, less systemic side effects from vaginal creams Lotions Easily absorbed, can cover large areas of the body, effective for hairy areas Vaginal creams can be messy

Topical Dosage Forms (continued) • Dispensing and administration pearls – Gloves should be worn when applying nitroglycerin, capsaicin, and potent topical steroids. – Topical steroids should be applied sparingly and not covered with bandages. – Some topical steroids available in different salts which are not interchangeable.

In the Know: True or False • An ointment is a W/O emulsion. true • A cream is an O/W emulsion. true • Ointments are often more cosmetically acceptable than creams. false

Inhalation Dosage Forms • Inhaled via the oral respiratory route • Metered-dose inhalers (MDI) – Handheld, propellantdriven device which provides a specific measured amount of medication – Examples: Ventolin, Proventil, Advair HFA

Inhalation Dosage Forms (continued) Proper Technique for Administration of an MDI

Inhalation Dosage Forms (continued) • Sterile solutions and nebulizers – Delivered as a mist through an atomizing machine called a nebulizer – Sterile water for injection (SWI) and normal saline (NS) used as vehicles to deliver medication into the lung – Device will aerosolize both the medication and the vehicle

Inhalation Dosage Forms (continued) • Micronized powders and nonaerosolized inhalers – Breath-activated powder used to avoid propellants – Uses a discus to administer a higher concentration of drug as a micronized powder into the lungs – Provides a controlled release of active ingredient

Inhalation Dosage Forms (continued) Dosage form Advantages Disadvantages MDI Rapid onset of action May be difficult to administer for patients with poor hand-eye coordination Nebulized medication Higher dose of medication delivered, faster onset of action Larger amount of medication may lead to higher risk of side effects

Inhalation Dosage Forms (continued) • Dispensing and administration pearls – If taking more than one MDI, the immediate-acting drug should be given first followed by the second one 5 to 10 minutes later. – Spacer devices recommended for pediatric and elderly patients – After administration of an inhaled steroid, the mouth should be rinsed. – Mouthpiece of inhaled steroid MDI should be washed with soap and water at least twice weekly.

Parenteral Dosage Forms • A sterile or microbial-free solution that is administered with a needle inserted through one or more layers of the skin • Greek roots: Para means beside, enteron means intestine. This route of administration goes “beside” rather than through the GI tract, thereby bypassing it.

Parenteral Dosage Forms (continued) • Intravenous (IV) – Administered through a vein directly into the bloodstream – Examples: antibiotics, chemotherapy, nutrition, critical care medications • Intramuscular (IM) – Administered into muscle – Examples: Epi. Pen, flu vaccine, antipsychotic medications

Parenteral Dosage Forms (continued) • Subcutaneous – Administered under the skin – Examples: insulin, pneumonia and shingles vaccines, Epi. Pen (either IM or subcutaneous) • Intradermal (ID) – Administered into the dermal layer of the skin – Examples: allergy testing, diagnostic testing (tuberculosis), local anesthesia Although the abbreviations SQ and SC are still used, this practice should be discouraged due to the risk of medication error.

Parenteral Dosage Forms (continued)

Parenteral Dosage Forms (continued) • Dispensing and administration pearls – Syringe • A calibrated device used to draw up, measure, and deliver medication through a needle • Insulin syringes available as 30 units (0. 3 ml), 50 units (0. 5 ml), and 100 units (1 ml) • Concentration of insulin vials is 100 units/ml • Proper size of insulin syringe determined by the dose

Parenteral Dosage Forms (continued) Common Types of Syringes (a) Insulin syringes in 30 unit, 50 unit, and 100 unit sizes (b) Tuberculin syringes (c) Hypodermic syringes

Parenteral Dosage Forms (continued) • Dispensing and administration pearls – Needle • Attached to the tip of a syringe • Used to draw fluid into the syringe or push fluid out of the syringe • The gauge of a needle corresponds to the size of the lumen (inner core) • The higher the gauge, the smaller the needle core • Diabetic patients use 28 to 32 gauge needles that are short, fine, or ultrafine. Remember that the higher the gauge number of a needle, the smaller the lumen. Conversely, the lower the gauge number of a needle, the larger the lumen.

Parenteral Dosage Forms (continued) Insulin vials Insulin pens • Multi-dose vial • Insulin is drawn up into a special syringe with an attached needle • Multiple steps to draw up and administer • Portable device • Insulin is “dialed up” • More convenient and easier to transport than vials/syringes • Do not require purchase of syringes and needles • Deliver more accurate dosages • Easier to use • Less injection pain • Retain memory of past injections • Disposable • Disadvantage is cost

Parenteral Dosage Forms (continued) • Dispensing and administration pearls Pharmacy personnel should inform patients taking insulin to roll the medication vials between their hands to agitate and warm the insulin. Insulin vials should never be shaken. – Insulin storage • Must be protected from temperature extremes • Unopened insulin vials or pens should be refrigerated • Opened vials or insulin pens can be stored at room temperature and discarded after one month

Parenteral Dosage Forms (continued) Route of administration Advantages Disadvantages Intravenous (IV) Act rapidly Inability to retrieve the medication if an adverse or allergic reaction occurs, potential for introducing microbes or pyrogens. Intramuscular (IM) Convenient, duration of action longer than with IV route, practice for use outside the hospital setting. Onset of response slower than with IV route, unpredictable absorption rate.

In the Know: Fill in the Blank • When using a _____, it is important to inhale slowly at the same time it is activated. metered-dose inhaler (MDI) • Insulin is administered by the ____ route. subcutaneous • Opened vials of insulin may be stored at room temperature for up to ______. one month

Drug Delivery Systems • A dosage form designed to modify the release of a drug by one or more pharmacokinetic parameters (absorption, distribution, elimination) • Results in products with improved efficacy and safety • Optimizes disease control and patient outcomes

Drug Delivery Systems (continued) • Delayed-Release Formulations (DR) – Have a special coating to delay absorption of the medication and to resist breakdown by gastric acid – Reduces risk of nausea or stomach upset – Enteric coated products • An example of a delayed-release formulation • Coating protects the stomach • Examples: enteric-coated aspirin, potassium chloride Pharmacy technicians should be aware that the protective or timed-release design characteristics of any delayed-release or extended-release oral formulations would be compromised if the medications were split or crushed.

Drug Delivery Systems (continued) • Extended-Release Formulation (XL) Pharmacy technicians should read drug labels carefully. A sustained -release (SR) dosage form is not the same as an extended-release (XL) dosage form of the same drug. – Allow a reduced frequency of dosing as compared with immediate-release medications – Sustained-release (SR) formulations • Less frequent dosage schedule • Example: buproprion SR given 2 to 3 times daily, buproprion immediate release given 3 to 4 times daily – Controlled-release (CR) formulations • At least a twofold reduction in dosing frequency from the immediate release or SR product • Example: Wellbutrin XL given once daily

Drug Delivery Systems (continued) • Transdermal patch – A drug contained within a patch or disk is absorbed through the skin. – A slow-release, steady level of drug enters the system. – Absorption is affected by thickness of the skin and blood flow, which vary with age. – Examples: nicotine, nitroglycerin, scopolamine

Chapter Summary • Drugs are administered in many dosage forms. • The oral route of administration allows medication to be absorbed through the digestive tract. • The transmucosal route of administration allows medication to be absorbed through the mouth, eyes, ears, nose, rectum, vagina, or urethra. • The topical route of administration allows medication to be absorbed through the skin. • The inhalation route of administration allows medication to be absorbed through the oral respiratory route.

Chapter Summary (continued) • The parenteral route of administration includes the injection of any drug or fluid into the bloodstream, muscle, or skin. • Needles come in various lengths and sizes. • Insulin is a common medication administered via the subcutaneous route. • Drug delivery systems are dosage forms whose design affects the delivery of the drug.