6 Dosage Formulations and Routes of Administration Sources

6 Dosage Formulations and Routes of Administration

Sources of Drugs • Natural drug sources § Occur in nature and are naturally occuring § Derived or extracted from plants, animals, and minerals

Sources of Drugs • 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

Sources of Drugs • 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

Sources of Drugs • 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)

Sources of Drugs • 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

Sources of Drugs • 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

Sources of Drugs • 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

Sources of Drugs • Synthetic drug sources § Examples of synthetic drugs • Barbiturates • Synthetic CNS depressants • Oxy. Contin • Synthetic opiate for pain management

Sources of Drugs • Genetically engineered drug sources § Recombinant DNA • Combining two different DNA strands to produce a new strand of DNA or r. DNA • Human insulin created to treat diabetes • Recombinant hepatitis B vaccine

Sources of Drugs • 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 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

Drug Nomenclature • 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

Drug Nomenclature • 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 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 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.

Dosage Formulations • Solid dosage forms § Most widely available form § Can be administered orally, rectally, vaginally, or topically § Advantages and disadvantages

Dosage Formulations • 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.

Dosage Formulations • Solid dosage forms § Tablets • Molded tablets made with mold and wet materials • Compressed tablets formed by diepunching compressed, powdered, crystalline, or granular substances into a uniform shape, usually has a film, sugar coating, or enteric coating

Dosage Formulations • 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.

Dosage Formulations • 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.

Dosage Formulations • 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.

Dosage Formulations • 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

Dosage Formulations • 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

Dosage Formulations • 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

Dosage Formulations • Solid dosage forms § Medicated sticks • For topical application of local anesthetics, sunscreens, antivirals, antibiotics, and cosmetics

Dosage Formulations • 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.

Dosage Formulations • 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.

Dosage Formulations • Semisolid dosage forms § Ointments are applied externally to the 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

Dosage Formulations • Semisolid dosage forms § Ointments are applied externally to the 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

Dosage Formulations • 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.

Dosage Formulations • Liquid dosage forms § Solutions • Viscous aqueous solutions use purified/sterile water; thick, sticky— either liquid or semisolid; syrups, jellies, and mucilages.

Dosage Formulations • Liquid dosage forms § Solutions • Nonaqueous solutions don't use water, usually alcohol, glycerin, or propylene glycol.

Dosage Formulations • 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%.

Dosage Formulations • 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.

Dosage Formulations • 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.

Dosage Formulations • 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.

Dosage Formulations • 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

Dosage Formulations • Suspensions § Usually intended for oral ingestion where large amount of medication is needed. § Other routes • Ophthalmic, parenteral, otic, and rectal

Dosage Formulations • Suspensions § Magmas and milks • Suspensions of undissolved medications in water § Lotions • For external use only

Dosage Formulations • 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

Dosage Formulations • Suspensions § Tinctures • Extractive alcoholic and hydro-alcoholic solutions; each m. L of tincture = 100 mg of crude ingredient § Fluidextracts • More potent than tinctures; each m. L = 1, 000 mg of crude drug

Dosage Formulations • Suspensions § Extracts • Similar to tinctures and fluidextracts but potency of crude drug is 2– 6 times stronger

Dosage Formulations • 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

Dosage Formulations • 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

Dosage Formulations • 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

Dosage Formulations • Inhalants § Fine powder or solution delivered as mist into nose or mouth, immediately entering respiratory tract § Asthma inhalers and allergy nasal sprays

Dosage Formulations • Aerosols § Very fine liquid or solid particles mixed in vehicle, packed with gas and pressure, administered via respiratory tract or topically

Delayed 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 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.

Routes of Administration • 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 selfadminister

Routes of Administration • Oral § Disadvantages • Hard to swallow for those who are children, elderly, unconscious, ventilated, or having digestion problems • Take longer to absorb and distribute

Routes of Administration • 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

Routes of Administration • 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

Routes of Administration • 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

Routes of Administration • 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.

Routes of Administration • Parenteral § Intradermal (ID) • Injection into top layers of skin § Subcutaneous (SC) • Injection into tissue under the skin

Routes of Administration • Parenteral § Intramuscular (IM) • Injection into large muscle masses, such as upper arm, thigh, buttock § Intravenous (IV) • Medication administered directly into vein

Routes of Administration • 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

Routes of Administration • Parenteral § Other parenteral routes include: • Intracardiac • Injection into heart • Intraperitoneal • Injection into abdominal or peritoneal cavity • Intrapleural • Injection into sac (pleura) surrounding lungs

Routes of Administration • Parenteral § Other parenteral routes include: • Intrathecal • Injection into cerebrospinal fluid around spinal cord • Intraventricular • Injecting antibiotics or chemotherapy agents into brain cavities (ventricles)

Routes of Administration • Parenteral § Other parenteral routes include: • Intravesicular • Injection into urinary bladder • Intravitreal • Injection into vitreous body of the eye

Routes of Administration • 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

Routes of Administration • 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

Routes of Administration • 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

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

Summary • 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.