6 Dosage Formulations and Routes of Administration.

Dosage Formulations and Routes of Administration

6

Sources of DrugsSources of Drugs

• Natural drug sources Occur in nature and are naturally

occuring Derived or extracted from plants,

animals, and minerals


• Natural drug sources Plant sources include:• Acetylsalicyclic acid (aspirin) derived

from white willow bark• Cocaine derived from the coca plant• Codeine and morphine derived from the

opium poppy plant


• Natural drug sources Animal sources include:• Bovine insulin derived from cow pancreas• Porcine insulin derived from pig pancreas• Pepsin derived from cow stomach• Thyroid hormones derived from pig

thyroid gland


• Natural drug sources Mineral sources include:• Ferrous sulfate (iron) to treat iron

deficiencies• Gold used to treat arthritis• Magnesium for milk of magnesia (laxative

and antacid)


• Natural drug sources Mineral sources include:• Potassium to supplement low potassium

levels• Sodium chloride is common base solution

for IV therapies• Zinc for skin protectants and sunscreen


• Synthetic drug sources Produced in a laboratory, not naturally

occuring Semisynthetic: naturally occuring

substance that has been chemically altered

Synthesized: made in laboratory to imitate a naturally occurring drug


• Synthetic drug sources Examples of synthetic drugs• Adrenalin• Synthesized epinephrine for treating

hypersensitivity and asthma attacks• Amoxicillin, ampicillin, and piperacillin• Semi-synthetic pencillins to treat various

infections


• Synthetic drug sources Examples of synthetic drugs• Barbiturates• Synthetic CNS depressants

• OxyContin• Synthetic opiate for pain management


• Genetically engineered drug sources Recombinant DNA• Combining two different DNA strands to

produce a new strand of DNA or rDNA • Human insulin created to treat diabetes• Recombinant hepatitis B vaccine


• Genetically engineered drug sources Monoclonal antibodies (MAbs)• Hybrid cells created in laboratory from

animals; used to treat tumors and diagnose various conditions• Rituxan, Zevalin, Erbitux, Avastin: used in

the treatment of various cancers

Drug NomenclatureDrug Nomenclature

• Chemical name Reflects the chemical structure of the

compound Often long and hard to remember and

pronounce Named according to guidelines from the

International Union of Pure and Applied Chemistry (IUPAC)

Used primarily in research settings


• Generic name Convenient and concise Assigned by manufacturer in

collaboration with the FDA Not capitalized May be used by anyone—not restricted

by copyright or tradmark Used in the USP and the USP-NF


• Trade or brand name Registered or trademarked by a specific

producer or manufacturer to identify its particular drug

This name cannot be used by other manufacturers but a generic may be sold under more than one trade name.

Usually capitalized Also called the "proprietary name"

Classification of DrugsClassification of Drugs

• Classifications based on: Chemical ingredients Method by which the drug is used Area of the body that is treated

• Two usual classification methods Therapeutic use Mechanism of action

Dosage FormulationsDosage Formulations

• Dosage forms How medication is prepared for

administration to the patient Solid or liquid Single medication may be available in

multiple dosage forms for use at various disease states, patient ages, and desired results.


• Solid dosage forms Most widely available form Can be administered orally, rectally,

vaginally, or topically Advantages and disadvantages


• Solid dosage forms Tablets• Small formed shapes usually taken by

mouth• Active and inert ingredients work

together to ensure tablet is easy to swallow, taste, digestible, and releases drug at proper time.


• Solid dosage forms Tablets• Molded tablets made with mold and wet

materials• Compressed tablets formed by die-

punching compressed, powdered, crystalline, or granular substances into a uniform shape, usually has a film, sugar coating, or enteric coating


• Solid dosage forms Tablets• Caplets are film-coated tablets in the

shape of a capsule.• Chewable tablets should be chewed for

desired results.• Effervescent tablets dissolve in liquid

before administration.• Fast dissolving tablets can be taken orally

without water.


• Solid dosage forms Tablets• Sublingual tablets disintegrate and are

absorbed under the tongue.• Buccal tablets disintegrate in the buccal

pouch, between the gums and the cheek.• Vaginal tablets are dissolved and

absorbed through the mucous lining of vagina.


• Solid dosage forms Capsules have drug contained in a shell• Soft gelatin shells are soft and elastic,

flexible during administration, and can't be broken apart.• Hard gelatin shells have two oblong

halves joined together, which can be separated if necessary.


• Solid dosage forms Lozenges (also called pastilles or

troches)• Hard, disk-shaped solid form in a sugar

base• Remains in the patient's mouth until has

been completely dissolved and all medication releases


• Solid dosage forms Powders• Usually produced in large supplies for

bulk compounding• Can be used internally or externally• Individual doses packaged in a powder

paper


• Solid dosage forms Granules• Made from wetted then dried powders

ground into course, nonuniform particles• Commonly used in pediatric antibiotic

suspensions• Dissolved in distilled water


• Solid dosage forms Medicated sticks• For topical application of local

anesthetics, sunscreens, antivirals, antibiotics, and cosmetics


• Semisolid dosage forms Suppositories • Administer medication via rectum, vagina,

or urethral tract• Melt or dissolve at body temperature• Used for babies and other instances where

oral dosing may not be practical Creams may or may not contain

medication; oil-in-water or water-in-oil bases.


• Semisolid dosage forms Ointments are applied externally to the

skin or mucous membranes.• Oleaginous ointments: emollients to

soothe and cool. Hydrophobic, meaning not easy to wash off.



skin or mucous membranes.• Water-soluble ointments: contain no fat

or water, easily wash off. Can be mixed with nonaqueous or solid medication• Anydrous ointments: absorb water,

turning into a water-in-oil emulsion



skin or mucous membranes.• Emulsions• Emollient bases made of water-in-oil

(occlusive) or oil-in-water (nonocclusive)• Pastes• Stiff or very viscous ointments that do not

melt or soften at body temperature; usually contain at least 20% solids


• Liquid dosage forms Solutions• Medication is completely dissolved and

evenly distributed (homogeneous) and quickly absorbed• Aqueous solutions use purified/sterile

water as vehicle for douches, irrigating solutions, enemas, washes, and sprays.


• Liquid dosage forms Solutions• Viscous aqueous solutions use

purified/sterile water; thick, sticky—either liquid or semisolid; syrups, jellies, and mucilages.


• Liquid dosage forms Solutions• Nonaqueous solutions don't use water,

usually alcohol, glycerin, or propylene glycol.


• Liquid dosage forms Solutions• Hydro-alcoholic solutions use alcohol and

water as vehicle or dissolving agent. Example:• Elixirs: liquid preparations with flavored

water and alcohol mixtures for oral administration. Many drugs dissolve more easily this way. Range of alcohol contents varies from 2–30%.


• Liquid dosage forms Solutions• Hydro-alcoholic solutions use alcohol and

water as vehicle or dissolving agent. Example:• Aromatic elixirs are nonmedical, used to

mask unpleasant medicine taste.


• Liquid dosage forms Solutions• Alcoholic solutions use no water, usually

ethyl or ethanol alcohols.• Collodions contain pyroxylin, applied to

skin, can carry an added medication• Spirits contain volatile and aromatic

substances, administered internally or inhaled.


• Liquid dosage forms Solutions• Alcoholic solutions use no water, usually

ethyl or ethanol alcohols.• Glycerite contains medication dissolved in

glycerin, then is mixed into a water or alcohol vehicle, often has viscous, jelly-like consistency, rarely used today.


• Suspensions Contain very fine solid particles mixed

with gas, liquid, or solid Break down faster than tablets or

capsules Must be shaken well before use


• Suspensions Usually intended for oral ingestion

where large amount of medication is needed.

Other routes• Ophthalmic, parenteral, otic, and rectal


• Suspensions Magmas and milks• Suspensions of undissolved medications

in water Lotions• For external use only


• Suspensions Gels• Similar to magmas and milks but

particles are smaller, used for oral or topical administration

Extractives• Drug extracted by soaking dried plant or

animal tissue in solvent


• Suspensions Tinctures• Extractive alcoholic and hydro-alcoholic

solutions; each mL of tincture = 100 mg of crude ingredient

Fluidextracts• More potent than tinctures; each mL =

1,000 mg of crude drug


• Suspensions Extracts• Similar to tinctures and fluidextracts but

potency of crude drug is 2–6 times stronger


• Emulsions Mixtures of water and oil (which

normally do not mix) Internal phase: one liquid broken into

small elements External (or continuous) phase: the

other liquid remains liquid Emulsifying agent added to keep two

liquids from seperating


• Liniments Applied to skin with friction and rubbing Can be solutions, suspensions, or

emulsions Contain medication that mildly irritates

skin, producing counterirritation or inflammation to relieve inflammation of deeper tissues or muscles

Ben-Gay most common OTC liniment today


• Transdermal patches Medicated adhesives that deliver

medication directly into bloodstream through the skin

Prescription and OTC applications• Sprays

Pump-type dispenser delivers medication nasally or translingually for quick absorption and onset


• Inhalants Fine powder or solution delivered as

mist into nose or mouth, immediately entering respiratory tract

Asthma inhalers and allergy nasal sprays


• Aerosols Very fine liquid or solid particles mixed

in vehicle, packed with gas and pressure, administered via respiratory tract or topically

Delayed and Extended ReleasesDelayed and Extended Releases

• Medications released over a period of time Extended release (ER) Long acting (LA) Sustained release (SR) Time release (TR) Controlled release (CR)

Routes of AdministrationRoutes of Administration

• Method by which medication is introduced into the body for absorption and distribution

• Varies from patient to patient Factors include patient's age,

consciousness, medical condition, time to achieve results, and side effects.


• Oral Abbreviation: PO (per os, Latin for "by

mouth") Advantages• Safe, convenient, easy to store; readily

available; lower cost, immediate release or extended release; easy to self-administer


• Oral Disadvantages• Hard to swallow for those who are

children, elderly, unconscious, ventilated, or having digestion problems• Take longer to absorb and distribute


• Oral Sublingual• Tablets administered under the tongue,

bypassing the digestive system and diffusing directly into the blood supply

Buccal• Tablets and lozenges/troches

administered between the gum and cheek, absorbed into bloodstream through mucous membranes


• Transdermal (percutaneous) Generally uses patch applied to skin Delivers medication to bloodstream Two kinds of patches• One controls rate of delivery to skin and

bloodstream• One lets skin control rate of delivery


• Inhalation Medication inhaled through mouth

directly into lungs Effective for lung conditions when

immediate relief is needed• Nasal

Inhaled through nose and absorbed into the bloodstream

Sprayed into nose for local effects


• Parenteral Medication does not pass through the

gastrointestinal system. Quicker absorption and distribution Convenient for those who cannot take

medicine orally Varied rate of delivery Dosage must be correct because action

is immediate and unreversable.


• Parenteral Intradermal (ID)• Injection into top layers of skin

Subcutaneous (SC)• Injection into tissue under the skin


• Parenteral Intramuscular (IM)• Injection into large muscle masses, such

as upper arm, thigh, buttock Intravenous (IV)• Medication administered directly into

vein


• Parenteral Other parenteral routes include:• Implant• Device inserted into the body to slowly

release medication• Intra-arterial• Injection into artery

• Intra-articular• Injection within joint


• Parenteral Other parenteral routes include:• Intracardiac• Injection into heart

• Intraperitoneal• Injection into abdominal or peritoneal

cavity• Intrapleural• Injection into sac (pleura) surrounding

lungs


• Parenteral Other parenteral routes include:• Intrathecal• Injection into cerebrospinal fluid around

spinal cord• Intraventricular• Injecting antibiotics or chemotherapy

agents into brain cavities (ventricles)


• Parenteral Other parenteral routes include:• Intravesicular• Injection into urinary bladder

• Intravitreal• Injection into vitreous body of the eye


• Topical Administered externally to the skin Absorbed into the mucous membrane,

preventing particles from being absorbed into the bloodstream

• Rectal Administered through the rectum for

local or systemic effects


• Vaginal Medications inserted into vagina for

absorption and distribution for local or systemic conditions

• Ophthalmic Solutions, ointments, suspensions, or

gels administered through the eye Treats conditions of the eye directly


• Otic Medications administered in the ear to

treat infections, inflammation, and severe wax buildup

Solutions and suspensions absorbed in the ear canal for immediate relief

SummarySummary

• Drug sources, nomenclature, common dosage forms, routes of administration

SummarySummary

• Important to: Dispense proper dosage form of

medication Dispense proper dosage amount,

especially for parenteral ROAs• Pharmacy technician must understand

drug names, the meaning and use of each dosage form and ROA.

6 Dosage Formulations and Routes of Administration.

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