Pharmacology: Routes of Administration, Dosage Forms, and Drug Delivery Systems

Comprehensive practice flashcards covering pharmacology routes of drug administration, oral solid and liquid dosage forms, parenteral injections, topical and transdermal systems, inhalation technologies, and clinical pharmacy considerations.

How is a route of administration (ROA) defined?

The pathway by which a drug enters the body to reach its site of action, indicating the part of the body on which, through which, or into which the medication is introduced.

How is a dosage form defined?

The physical form or structure in which a drug substance and inactive excipients are produced and dispensed to enable safe, effective, and convenient delivery to the body.

What is the key distinction between a dosage form and a route of administration?

The dosage form describes the physical appearance and formulation of the medication, whereas the route of administration describes the anatomical pathway through which the drug enters the body.

Which official Canadian database is utilized by pharmacy personnel to confirm a drug's approved route of administration and dosage form?

Health Canada's Drug Product Database (DPD).

When looking up fluticasone $50\,\mu\text{g}$ nasal spray in the Drug Product Database (DPD), what are the listed drug, strength, dosage form, and route?

The drug is fluticasone, the strength is $50\,\mu\text{g}/\text{actuation}$, the dosage form is spray (metered dose), and the route of administration is nasal.

What is meant by the pharmaceutical term "metered dose"?

A drug delivery device that discharges a pre-measured, specific amount of medication with each individual actuation.

What is the definition of "off-label use" in pharmacy practice?

The use of a pharmaceutical drug for an unapproved indication, an unapproved age group, an unapproved dosage, or an unapproved route of administration.

What is an off-label administration route for oral progesterone capsules?

Vaginal administration (inserted into the vagina).

What is an off-label use for fluticasone metered dose aerosol typically intended for oral inhalation?

Topical cutaneous application for dermatitis.

Why is verifying both the dosage form and the route of administration essential for patient safety?

Administering a drug via the incorrect route can lead to reduced therapeutic efficacy or cause severe patient harm.

What is an Active Pharmaceutical Ingredient (API)?

The active chemical substance within a pharmaceutical formulation that produces the desired therapeutic effect.

What is an excipient and what roles does it play in a drug product?

A pharmacologically inert inactive ingredient critical for pharmaceutical performance, such as enhancing stability, controlling drug delivery, improving solubility, or masking unpleasant tastes.

What pharmaceutical formula represents the composition of a finished drug product?

$$\text{Active Pharmaceutical Ingredient (API)} + \text{Excipients} = \text{Drug Product}$$

What are the two primary classification systems used to categorize pharmaceutical dosage forms?

Classification by overall physical characteristics/properties (solid, liquid, semi-solid, gaseous) and classification by route of administration (oral, topical, parenteral, inhalation, etc.).

Why is familiarity with diverse routes of administration and dosage forms essential for pharmacy technicians?

It directly impacts drug efficacy, safety, and handling, and enables technicians to provide accurate patient instructions to optimize therapy.

Why are solid oral dosage forms like tablets and capsules produced in multiple milligram ($\text{mg}$) or microgram ($\mu\text{g}$) strengths?

To ensure accurate and flexible dosing tailored to the specific therapeutic needs and tolerances of diverse patient populations.

How do pharmaceutical dosage forms protect active drug substances from environmental degradation?

Formulations such as coated tablets or amber, sealed ampoules protect light-, moisture-, and oxygen-sensitive drugs from chemical breakdown.

How do enteric-coated dosage forms protect acid-labile drugs?

They provide an acid-resistant polymer barrier that prevents dissolution in stomach acid, preserving the drug until it reaches the alkaline intestine.

How do specific liquid formulations overcome the poor solubility of raw active pharmaceutical ingredients?

They incorporate suitable solvents, suspending agents, or emulsifiers into suspensions, emulsions, or solutions to facilitate uniform administration.

Which dosage form modifications improve patient adherence when drugs have an unpalatable taste or odor?

Sugar coatings, film coatings, flavored syrups, and oral lozenges.

How do sustained-release (SR) and controlled-release (CR) dosage forms optimize patient dosing schedules?

They extend drug release over prolonged periods, maintaining steady blood levels and reducing daily dosing frequency to once or twice daily.

How does targeted site-specific drug delivery maximize therapeutic efficacy while limiting toxicity?

It deposits high drug concentrations directly at the target site (such as inhalers into the bronchi or eye drops onto the ocular surface) while minimizing systemic circulation exposure.

What defines a local route of drug administration?

Direct application of a drug to or near the desired site of action to produce a targeted local effect with minimal systemic absorption.

What defines a systemic route of drug administration?

Administration where the drug enters the bloodstream and circulates throughout the entire body to produce widespread effects.

Which administration routes are primarily utilized for local therapy?

Topical (dermal), ophthalmic, otic, oral inhalation for airways, local vaginal, local rectal, oral cavity (buccal/sublingual for mouth/throat), and intra-articular injections.

Which broad categories of routes achieve systemic drug action?

Enteral routes, parenteral injection routes, transdermal delivery systems, and systemic transmucosal routes (transnasal, pulmonary, buccal, sublingual, rectal, and vaginal).

What is the primary therapeutic rationale for applying topical hydrocortisone, clotrimazole, or mupirocin to the skin?

To treat localized inflammation, superficial fungal infections, or bacterial lesions directly with negligible systemic absorption.

Why is intra-articular injection classified as a local parenteral route?

Because the drug (e.g., triamcinolone suspension) is injected directly into a synovial joint space to alleviate local inflammation, maximizing local bioavailability while avoiding systemic adverse effects.

What mandatory label instruction must be provided to the patient on a prescription for an intra-articular steroid injection?

"For injection by health care professional".

What does the enteral route of drug administration encompass?

Drug delivery through any part of the gastrointestinal tract (GIT), including oral (PO), sublingual (SL), buccal, orally disintegrating tablets (ODTs), nasogastric (NG) tube, and rectal (PR) administration.

What does the Latin abbreviation "PO" (per os) indicate on a medication prescription?

The oral route of administration (by mouth).

What are the primary clinical advantages of administering drugs by the oral route?

It is convenient, non-invasive, cost-effective, easily self-administered by patients, and accommodates a wide variety of solid and liquid formulations.

What gastrointestinal factors contribute to variable oral drug bioavailability?

Gastric pH, food intake, digestive enzymes, gastric emptying time, and first-pass hepatic metabolism.

What is the first-pass effect (hepatic first-pass metabolism)?

The extensive metabolism of an orally swallowed drug by enzymes in the liver and gastrointestinal wall before reaching the systemic circulation, which substantially reduces the drug's bioavailability.

For which patient populations are traditional solid oral dosage forms often contraindicated or impractical?

Unconscious patients, patients experiencing persistent nausea and vomiting, and individuals with dysphagia (difficulty swallowing), such as young children and elderly patients.

What are the advantages of oral liquid dosage forms over solid tablets and capsules?

Faster absorption because they bypass tablet disintegration, ease of swallowing for pediatric and dysphagic patients, and flexible, precise individual dose titration.

What are the major disadvantages associated with oral liquid dosage forms?

They are bulkier to transport, less chemically and microbially stable, prone to measuring errors if calibrated devices are omitted, and often unpalatable.

What calibrated tools should be provided to ensure accurate dosing of oral liquids?

An oral syringe or a calibrated oral dropper.

How does the sublingual (SL) route deliver medication into systemic circulation?

The tablet is placed under the tongue, dissolving in saliva so the active drug absorbs directly across the sublingual mucosa into the bloodstream, bypassing the gastrointestinal tract and liver.

What are the key clinical advantages of sublingual nitroglycerin tablets for acute angina?

Rapid onset of action ($2\text{ to }5\,\text{minutes}$), avoidance of first-pass hepatic metabolism, and convenience without requiring water.

What are the primary disadvantages and physical constraints of the sublingual route?

It is limited to small doses of highly potent drugs that dissolve rapidly in saliva, can cause oral mucosal irritation, cannot provide sustained release, and may taste unpleasant.

How is the buccal route of administration executed?

The dosage form (tablet or film) is placed between the gum and the inner cheek lining (buccal pouch) to absorb through the vascular buccal mucosa directly into the systemic circulation.

What are the primary advantages and disadvantages of the buccal administration route?

Advantages: rapid absorption and avoidance of first-pass hepatic metabolism. Disadvantages: inconvenient to hold in place, restricted to small doses, and requires salivary stability.

Why did Health Canada issue a safety warning regarding Suboxone sublingual tablets and soluble film?

Suboxone sublingual tablets and soluble films are not bioequivalent at all doses and routes; substituting between them can alter buprenorphine and naloxone blood concentrations, risking inadvertent overdose, underdosing, or opioid withdrawal.

What is an orally disintegrating tablet (ODT) or rapidly disintegrating tablet (RDT)?

A solid dosage form designed to dissolve rapidly on or under the tongue within $< 30\,\text{seconds}$ without requiring water.

What are prominent examples of medications formulated as ODTs?

Risperidone ODT (Risperdal M-Tab), ondansetron ODT (Zofran ODT), and rizatriptan RDT.

What are the specific clinical advantages and packaging disadvantages of ODTs and RDTs?

Advantages: rapid dissolution, rapid absorption onset, and convenience for patients unable to swallow pills. Disadvantages: higher financial cost, structural fragility, and moisture sensitivity requiring blister protection.

Are conventional oral swallowing tablets and orally disintegrating tablets (e.g., ondansetron tablet vs. ondansetron ODT) interchangeable without authorization?

No, they have distinct formulations, kinetics, and administration techniques, making them non-interchangeable.

What is a nasogastric (NG) tube and what is its role in drug administration?

A thin, soft rubber or plastic tube inserted through the nose, past the throat, and into the stomach to deliver fluids and medications to patients unable to take oral formulations.

What does the Latin abbreviation "PR" (per rectum) signify on a prescription?

Administration via the rectum.

What clinical benefits make the rectal route useful for systemic drug delivery?

It can be used in vomiting, unconscious, or convulsing patients, accommodates dysphagic pediatric patients, and partially bypasses first-pass hepatic metabolism.

What are the main drawbacks and patient concerns associated with rectal drug administration?

Poor patient acceptance, inconvenient administration, slow or erratic mucosal absorption, risk of local mucosal inflammation, and temperature sensitivity requiring cool storage.

What are two clinical examples of rectal administration—one for systemic action and one for local action?

Systemic action: dimenhydrinate (Gravol) suppository for nausea and vomiting. Local action: Anusol or hydrocortisone suppository for hemorrhoids.

What is the transmucosal route of administration for systemic effect?

Delivery of active drug directly through mucous membranes (oral, nasal, rectal, or vaginal) into the bloodstream, bypassing the gastrointestinal tract and hepatic first-pass metabolism.

How does systemic transnasal (intranasal) drug delivery work?

Medication is sprayed or insufflated into the nasal cavity, absorbing rapidly through the highly vascular nasal mucosa directly into the bloodstream.

What is a distinctive packaging characteristic of intranasal sprays formulated for systemic effect?

They are typically packaged as single-dose delivery devices containing only one spray per unit.

What are three common examples of systemic transnasal medications and their therapeutic uses?

Narcan (naloxone nasal spray) for opioid overdose reversal, Zomig (zolmitriptan nasal spray) for acute migraines, and Baqsimi (glucagon nasal powder) for severe hypoglycemia.

What are the primary clinical advantages and disadvantages of transnasal systemic drug delivery?

Advantages: rapid onset comparable to IV, painless non-invasive administration, and complete avoidance of first-pass metabolism. Disadvantages: high formulation cost, restricted fluid volume limiting use to potent drugs, and variable absorption caused by nasal congestion.

What does the Latin abbreviation "PV" (per vagina) signify on a prescription?

Administration into the vagina.

What dosage forms are utilized for vaginal drug administration?

Vaginal tablets, inserts, suppositories (ovules), creams, ointments, gels, douches, and flexible vaginal rings.

Identify an example of a vaginal product used for local effect and one used for systemic effect.

Local effect: Canesten (clotrimazole) vaginal cream/tablet for fungal infections or Premarin cream for vaginal atrophy. Systemic effect: Estring or NuvaRing contraceptive ring for systemic hormone release.

What are the advantages and disadvantages of the vaginal administration route?

Advantages: bypasses hepatic first-pass metabolism and permits sustained local or hormonal therapy. Disadvantages: patient inconvenience, potential tissue irritation, and product leakage or messiness.

What is the etymological origin and medical definition of the "parenteral" route?

Derived from Greek "par" (beyond or outside) and "enteral" (intestine); refers to the administration of medications via injection or infusion, bypassing the alimentary tract.

Name seven distinct parenteral administration routes.

Intravenous (IV), intramuscular (IM), subcutaneous (SC), intra-articular, intra-arterial, intrathecal, and intradermal.

Why must all parenteral formulations be prepared under strictly sterile conditions using aseptic technique?

Because parenteral administration bypasses the body's natural defensive barriers (skin, mucous membranes, and gastrointestinal acid), creating a direct portal for systemic microbial contamination and infection.

What are the primary therapeutic advantages of intravenous (IV) administration?

$100\%$ systemic bioavailability, immediate onset of action, rapid achievement of target plasma concentrations, capacity to infuse large volumes, and bypass of gastrointestinal limitations.

What are the major clinical risks and disadvantages associated with intravenous (IV) drug delivery?

Invasiveness, need for skilled healthcare personnel, patient discomfort, risk of thrombophlebitis and systemic infection, and the inability to recall the dose once injected if an adverse event occurs.

What defines an intramuscular (IM) injection, and what are its common anatomical sites?

Injection of medication deep into muscle tissue, typically into the deltoid, gluteus, or thigh (vastus lateralis) muscles.

What is a "depot" formulation in intramuscular therapy?

A specialized injectable formulation designed to release active drug slowly from the muscle mass into circulation over weeks to months, decreasing administration frequency (e.g., Depo-Provera, aripiprazole).

What is the standard maximum volume that can be safely administered in a single intramuscular (IM) injection site?

Up to $10\,\text{mL}$.

What is a subcutaneous (SC, Subcut, Sub-Q) injection?

Injection of medication under the skin into the fatty subcutaneous tissue layer (e.g., insulin, heparin).

Why is rotating injection sites critical for patients receiving daily subcutaneous injections such as insulin?

To prevent local tissue damage, lipodystrophy, and scar tissue buildup, which cause erratic and compromised drug absorption.

What is an intradermal implant, and what active medication is delivered by the Nexplanon subdermal system?

A sterile polymer rod inserted beneath the skin to provide prolonged continuous drug release; Nexplanon delivers $68\,\text{mg}$ of etonogestrel for hormonal contraception.

What volume threshold distinguishes Small Volume Parenterals (SVPs) from Large Volume Parenterals (LVPs)?

Small Volume Parenterals have a volume of $100\,\text{mL}$ or less ($\le 100\,\text{mL}$), whereas Large Volume Parenterals exceed $100\,\text{mL}$.

What is an ampoule in parenteral packaging?

A sealed, single-use glass or plastic container that must be snapped open, containing sterile liquid medication formulated without antimicrobial preservatives.

How do single-use vials and multi-dose vials differ regarding preservatives?

Multi-dose vials contain antimicrobial preservatives to prevent bacterial proliferation during repeated rubber stopper punctures, whereas single-use vials contain no preservatives and must be discarded after one entry.

What is a lyophilized powder for injection, and how must it be handled before administration?

A freeze-dried sterile drug powder sealed in a vial that must be reconstituted with sterile water for injection or a specific manufacturer-supplied diluent before use.

What three dosage strengths of Penicillin G Sodium for Injection USP are shown on the manufacturer vials?

$1\,\text{million units}$, $5\,\text{million units}$, and $10\,\text{million units}$ per vial.

What are the pre-set dosages delivered by EpiPen Jr and EpiPen auto-injectors?

EpiPen Jr delivers $0.15\,\text{mg}/\text{injection}$ and adult EpiPen delivers $0.3\,\text{mg}/\text{injection}$.

Why can an injectable suspension never be administered via the intravenous (IV) or intrathecal routes?

Because insoluble suspended drug particles can cause vascular occlusion (pulmonary or cerebral emboli) or fatal neurotoxicity in the spinal fluid.

Identify the four key components labeled on this standard insulin cartridge.

1. Rubber septum (for pen needle penetration); 2. Aluminum crimp cap (seals cartridge); 3. Glass body (contains insulin solution); 4. Rubber plunger (moves forward to dispense insulin).

Identify the six main operating components of this reusable insulin pen.

1. Protective cap; 2. Single-use pen needle; 3. Cartridge holder; 4. Insulin cartridge; 5. Dose window (displays dialled units); 6. Dose dial / injection button.

What distinguishes cutaneous topical dosage forms from transdermal drug delivery systems?

Topical dosage forms are formulated for superficial local activity within the skin layers with minimal systemic absorption, whereas transdermal systems are engineered specifically to transport drugs across the stratum corneum into the bloodstream for systemic action.

What is the structural difference between an ointment and a cream?

Ointments are greasy, occlusive water-in-oil (w/o) semi-solids that hydrate dry skin; creams are non-greasy semi-solid emulsions (usually oil-in-water o/w) that rub in easily.

What is a paste in dermatology?

A very thick, stiff semi-solid formulation containing a high percentage of dispersed solid powder particles that forms an adherent protective layer over skin.

What is a liniment?

A fluid or semi-fluid liquid preparation, typically in an alcoholic or hydroalcoholic vehicle, intended to be rubbed frictionally onto the skin.

What are the clinical advantages and disadvantages of topical cutaneous medications?

Advantages: direct local effect, minimal systemic adverse effects, and non-invasiveness. Disadvantages: messiness, application variability (difficulty applying an exact dose), and reliance on skin barrier integrity.

What are the major advantages of transdermal patch delivery systems?

Controlled, zero-order-like drug delivery over extended intervals ($24\,\text{hours}$ to several days), complete avoidance of hepatic first-pass metabolism, and consistent dosing.

What are the physical constraints of transdermal patch systems?

The active drug must be highly potent with low daily dose requirements; otherwise, the required patch surface area becomes impractically large.

What is the proper procedure for safely disposing of a used transdermal patch?

Fold the patch in half with the sticky adhesive sides adhering firmly to each other, and dispose of it safely out of reach of children and domestic pets.

Identify the primary layers comprising a transdermal drug reservoir patch.

1. Protective peel strip/release liner; 2. Adhesive layer; 3. Rate-controlling release membrane; 4. Drug reservoir; 5. Impermeable backing layer.

What role does the release liner serve in a transdermal patch system?

It covers and protects the adhesive and drug surface during storage and must be peeled off and discarded immediately before application.

What role does the rate-controlling membrane perform in a reservoir transdermal patch?

It meters and restricts the rate of drug diffusion from the reservoir into the skin, ensuring sustained release over the labeled wear period.

What active drug, concentration, and dispensing container are shown for Estrogel?

$17\beta\text{-estradiol}$ ($0.06\%\,\text{w/w}$ as estradiol hemihydrate) packaged in an $80\,\text{g}$ metered-dose pump bottle for transdermal application.

If a prescription for Androgel $1\%$ pump specifies "apply $1.25\,\text{g}$ to abdomen daily", and $1\text{ pump actuation} = 1.25\,\text{g}$, how should the patient directions be written?

"Apply 1 pump to abdomen once daily".

What standard verb should pharmacy technicians use when creating prescription directions for topical dermatologic formulations?

"Apply".

What are pharmaceutical oral powders?

Dry, finely divided mixtures of active drugs and excipients supplied in bulk containers or pre-measured individual packets for oral use.

What is an example of an oral bulk laxative powder, and how is it supplied?

Lax-A-Day (polyethylene glycol 3350) supplied in large multi-dose bulk plastic containers.

What is an example of a single-dose oral packet (sachet) antibiotic powder?

Jamp-Fosfomycin powder (as fosfomycin tromethamine), containing $3\,\text{g}$ per single-dose sachet.

If a prescription for Cambia states "1 sachet daily", how should the patient label signatura be formulated?

"Dissolve the contents of 1 packet into 30 to 60 mL of water and drink once daily".