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Chapter 3. Drugs, Dose Forms, and Delivery Systems. Chapter 3 Topics. Pharmaceuticals Sources of Drugs Uses of Drugs Comparison of Dose Forms and Delivery Systems Solid Dose Forms Liquid Dose Forms Inhalation Dose Forms Delivery Systems Drug References. Learning Objectives.
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Chapter 3 Drugs, Dose Forms, and Delivery Systems
Chapter 3 Topics • Pharmaceuticals • Sources of Drugs • Uses of Drugs • Comparison of Dose Forms and Delivery Systems • Solid Dose Forms • Liquid Dose Forms • Inhalation Dose Forms • Delivery Systems • Drug References
Learning Objectives • Define the term drugand distinguish between over-the-counter and legend drugs • Explain the parts of a National Drug Code number • Categorize drugs by source as natural, synthetic, synthesized, or semisynthetic • Explain the uses of drugs as therapeutic, pharmacodynamic, diagnostic, prophylactic, and destructive agents
Learning Objectives • Define and differentiate between the terms dose form and delivery system • Enumerate and explain the properties and identify advantages and disadvantages of the major dose forms and delivery systems for drugs • Identify the function of various reference texts commonly used in pharmacy
Pharmaceuticals • Adrug is any substance taken into or applied to the body for the purpose of altering the body’s biochemical functions and thus its physiological processes • a medical substance or remedy used to change the way a living organism functions • also called a medication
Pharmaceuticals Drugs products contain many components: • anactive ingredient is the biochemically reactive component of the drug • inert ingredients or inactive ingredients have little or no physiological effect • stabilize the tablet or liquid formulation • provide the raw material for many topical creams and ointments • ensure sterility of injectable products • assist in the masking of unpleasant tasting medications for pediatric patients
National Drug Code (NDC) • A National Drug Code (NDC) number is a unique number assigned to a product • identifies the manufacturer, drug, packaging size, and type • appears on all drug labels • Contains ten characters • four or five digit labeler code, identifying the manufacturer or distributor of the drug • a three- or four- digit product code, identifying the drug (active ingredient and its dose form) • a two-digit package code
National Drug Code (NDC) • NDC bar code numbers are used • for drug recalls • to compare medications dispensed in the filling process to minimize medication errors
Parts of a National Drug Code (NDC) Number Visit the NDC Directory
Classes of Drugs Drugs are classified as over-the-counter (OTC) or legend • legend drugs can be dispensed only with a prescription from a healthcare professional licensed in that state • labeled with the legend, “Caution: Federal Law Prohibits Dispensing Without Prescription” or an equivalent symbol ( ) • the new legend in the updated labeling law is “ only” drug caution legend
Classes of Drugs • Drugs with potential for abuse are classified according to five drug schedules based on the potential for abuse and physical and psychological dependence • Schedule II drugs such as narcotics and amphetamines have a high potential for abuse and dependence • Schedule V cough syrups have a low potential for abuse and limited potential for creating physical or psychological dependence
Classes of Drugs • Over-the-counter drugs can be dispensed without a prescription • proven relatively safe to be sold without prescription • OTC drug labels • must contain all the information necessary for a consumer to safely take the medication Learn more about the Drug Facts label at the Consumer Healthcare Products Association Web site
Classes of Drugs • Diet supplements, especially herbs, should be considered drugs • can cause side effects, adverse reactions, and drug interactions • Do not have the same stringent controls as legend and OTC medications Learn more about independent testing of diet supplements by visiting ConsumerLab’s Web site
Classes of Drugs Safety Note • Diet supplements are considered “food supplements” to maintain health • a patient should not exceed the recommended daily dose without the knowledge of a physician • the pharmacy technician can assist the pharmacist by gathering information on patient use of diet supplements and adding this data to the computer profile
Classes of Drugs • Homeopathic medications are very small dilutions of natural drugs claimed to stimulate the immune system • Homeopathy is derived from the Greek words homos (i.e., similar) and pathos (i.e., suffering or disease)
Classes of Drugs Safety Note • Most homeopathics are OTC, but some are prescription only.
Discussion What are the differences between the various classes of pharmaceuticals?
Discussion What are the differences between the various classes of pharmaceuticals? Answer: OTCs may be purchased without prescriptions while legend drugs require a prescription from an authorized practitioner; controlled substances have abuse potential, and homeopathic medications are natural extracts, usually OTC.
Terms to Remember • drug • active ingredient • inert ingredient • National Drug Code (NDC) • over-the-counter (OTC) • homeopathic medications
Sources of Drugs • Drugs come from various sources • Can be classified as: • natural • synthetic (created artificially) • synthesized (created artificially but in imitation of naturally occurring substances) • semisynthetic (containing both natural and synthetic components)
Drugs from Natural Sources • Some drugs are naturally occurring biological products • made or taken from single-celled organisms, plants, animals, and humans • Many herbal products come from natural sources • Modern-day drugs from natural sources include: • penicillin (extracted from certain molds) • acetylsalicylic acid, commonly known as aspirin, is derived from the bark of the white willow tree
Synthetic, Synthesized, and Semisynthetic Drugs • A synthesized drug is a drug that is created artificially • A synthetic drug is a drug that is created artificially in imitation of naturally occurring substances • to exert a specific pharmacologic effect • A semisynthetic drug is a drug that is created artificially and contains both natural and synthetic components
Synthetic, Synthesized, and Semisynthetic Drugs • Biotechnology combines the science of biology, chemistry, and immunology to produce synthetic, unique drugs with specific therapeutic effects • These drugs can be created by means of the recombinant deoxyribonucleic acid(recombinant DNA) techniques of genetic engineering • using living organisms or parts of organisms for specific purposes such as creating a synthetic drug
Synthetic, Synthesized, and Semisynthetic Drugs • Deoxyribonucleic acid (DNA) is the complex, helically shaped molecule that carries the genetic code • Contains the instructions, or recipe, for creating messenger ribonucleic acid (mRNA) • mRNA contains the recipe for arranging amino acids into proteins for living organisms • By transferring a segment of recombined DNA into a host cell, scientists can change what proteins the cell produces
Modeling DNA (a) A single nucleotide. (b) A short section of a DNA molecule consisting of two rows of nucleotides connected by weak bonds between the bases adenine (A) and thymine (T), guanine (G), and cytosine (C). (c) Long strands of DNA twisted to form a double helix.
Synthetic, Synthesized, and Semisynthetic Drugs • Antibodies are a part of the immune system to neutralize antigens or foreign substances in the body • Monoclonal antibodies are pure antibodies produced in a laboratory against a known specific antigen • can be used to attack tumors and to diagnose a great variety of conditions • Genetic engineering is the hybridization techniques for creating MAbs
Synthetic, Synthesized, and Semisynthetic Drugs • The Human Genome Project is the mapping of the biochemical instructions that make up the human body in health and disease • potential disease can be identified at an earlier date, and new treatments can be specifically designed to treat them Learn more about the Human Genome Project
Discussion Give examples of drugs from various sources.
Discussion Give examples of drugs from various sources. Answer: Drugs may come from natural sources (quinine from cinchona bark), may be synthetic (barbiturates), or may be semisynthetic (semisynthetic penicillins), or may result from biotechnology (human insulin).
synthesized drug synthetic drug semisynthetic drug biotechnology recombinant deoxyribonucleic acid (recombinant DNA) deoxyribonucleic acid (DNA) ribonucleic acid (mRNA) antibodies monoclonal antibodies genetic engineering Terms to Remember
Uses of Drugs • Medications are used to: • treat and cure illness • aid in diagnosis • prevent illnesses • The action of a medication cannot be fully accounted for without considering the dose form selected
Therapeutic Agents • A therapeutic agent is any drug that helps to: • maintain health • relieve symptoms • combat illness • reverse disease processes
Pharmacodynamic Agents • A pharmacodynamic agent is one that alters bodily functioning in a desired way • stimulate or relax muscles • dilate or constrict pupils • increase or decrease blood sugar
Diagnostic Agents • A diagnostic agentfacilitates an examination or conclusion as to the nature or extent of a disease condition • Radiopharmaceuticalsare chemicals containing radioactive isotopes, used diagnostically (and also therapeutically) • nuclear pharmacy is the procuring, storage, compounding, dispensing, and provision of information about radiopharmaceuticals Get more information on nuclear pharmacy technician training programs at the American Pharmacists Association Web page
Prophylactic Agents • A prophylactic agent prevents illness or disease from occurring • antiseptic • germicidal liquid iodine • any vaccine is considered a prophylactic agent
Destructive Agents • A destructive agent has a -cidal action, meaning it kills bacteria, fungi, viruses, or even normal cells or abnormal cancer cells • many antibiotics are bactericidal (they kill bacteria) • radioactive iodine is used to destroy some of the thyroid gland in patients with hyperthyroidism • antineoplastic drugs used in cancer chemotherapy to destroy malignant tumors
Discussion Give examples of the various uses of drugs.
Discussion Give examples of the various uses of drugs. Answer: Drugs may be used to maintain health (aspirin to prevent heart attack), to relieve symptoms (analgesics), combat illness (antibiotics), or reverse disease processes (antihypertensives).
Terms to Remember • therapeutic agent • pharmacodynamic agent • diagnostic agent • radiopharmaceuticals • prophylactic agent • destructive agent • antineoplastic drug
Comparison of Dose Forms and Delivery Systems • Dose form refers to the physical manifestation of a drug as a solid, liquid, or gas that can be used in a particular way • common dose forms include tablets, capsules, creams, ointments, solutions, injections, and aerosols • Delivery system may mean any of the following: • device used to deliver the drug • design feature of the dose form that affects the delivery of the drug • means for transporting a drug to its site(s) of action within the body
Comparison of Dose Forms and Delivery Systems • Delivery systems differ in pharmacological properties • sites of action • rate of delivery • quantities of active ingredient delivered • Choice of delivery system depends on • active ingredient to be delivered • amount of active ingredient to be delivered • means or route by which ingredient is to be delivered • to what sites, at what rate, over what period of time, for what purpose
Terms to Remember • dose form • delivery system
Solid Dose Forms • used more frequently than any other form • are safest for self-administration
Tablets • A tabletis a solid dose form produced by compression containing one or more active ingredients and, commonly, other pharmacological ingredients including: • diluents • binders (promote adhesion of materials in tablet) • lubricating agents (give a sheen and aid in manufacturing process) • disintegrates (help break up ingredients) • solubilizers, colorings, flavorings
Tablets • Some tablets arescoredonce or twice to facilitate breaking into portions for half or even quarter doses • Unscored tablets should not be broken because the dose may not be equal in each piece • a tablet-splitter may be used for some unscored tablets • odd-shaped tablets are often difficult to cut, even with a tablet splitter
Tablets Safety Note • Careful tablet splitting may be a way to reduce medication costs, but it is not recommended for all drugs • Patients must be warned not to take a full tablet if such action would result in an overdose of medication
Tablets • Compression tablets are the most inexpensive and common dose form • Multiple compression tablets (MCTs) are produced by multiple compressions • created for appearance alone, to combine incompatible substances into a single medication, or to provide for controlled release in successive events, or stages (a) Two layers or compressions (b) Three layers or compressions
Tablets • A caplet is an oblong tablet that is a hybrid of the capsule and tablet • offers the advantage of easier swallowing than a large tablet and more stability (and longer shelf life) than a capsule • Most tablets are uncoated • A coating is a special outside layer that dissolves or ruptures at the site of application • Formulated to • mask bitter taste • prevent drug destruction in stomach • delay release of drug into the intestines
Tablets • Sugar-coated tablets (SCTs) contain an outside layer of sugar • protects the medication • improves appearance and flavor • BUT makes tablets much larger and heavier and more difficult to swallow • Film-coated tablets (FCTs) contain a thin outer layer of a polymer • thinner, lighter in weight, and cheaper to manufacture than sugar coatings • colored to provide an attractive appearance