ADVANCED
PHARMACOLOGY
FUNDAMENTALS
ANSWERED
2023/2024
, 1. What are the four main pharmacokinetic processes that determine the fate of a drug in the body? Explain how each
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process affects the drug concentration and action.
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- The four main pharmacokinetic processes are absorption, distribution, metabolism, and excretion. Absorption is the process
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of transferring the drug from the site of administration to the systemic circulation. Distribution is the process of delivering the
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drug to the tissues and organs. Metabolism is the process of transforming the drug into more polar and less active
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metabolites. Excretion is the process of eliminating the drug and its metabolites from the body. Each process affects the
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drug concentration and action by influencing the onset, duration, intensity, and variability of the pharmacological effects.
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2. What are the factors that affect drug absorption? Give an example of each factor and explain how it influences the rate and
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extent of absorption.
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- The factors that affect drug absorption are physicochemical properties of the drug, formulation and route of
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administration, physiological factors, and pathological factors. For example, a drug with high lipid solubility, low molecular
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weight, and non-ionized form can cross biological membranes more easily and have faster and higher absorption. A drug
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given orally may have lower and slower absorption than a drug given intravenously due to the first-pass effect in the
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liver. A drug may have altered absorption in patients with gastrointestinal disorders, such as diarrhea, vomiting, or
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malabsorption syndrome.
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3. What are the advantages and disadvantages of oral route of administration? Name two types of oral formulations and
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explain how they differ in terms of absorption and bioavailability.
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- The advantages of oral route of administration are convenience, safety, low cost, and suitability for sustained-release
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formulations. The disadvantages are variability, slow onset, first-pass effect, gastric irritation, food-drug interactions, and
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patient compliance. Two types of oral formulations are tablets and capsules. Tablets are solid dosage forms that contain
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one or more active ingredients compressed or molded into a shape. Capsules are gelatin shells that enclose a powder,
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liquid, or granule. Tablets may have different coatings or disintegrants that affect their dissolution and absorption. Capsules
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may have different sizes or materials that affect their dissolution and absorption. Generally, capsules have faster and
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higher absorption and bioavailability than tablets.
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4. What is the difference between plasma protein binding and tissue binding of drugs? How do they affect drug
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distribution and elimination?
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- Plasma protein binding is the reversible attachment of drugs to plasma proteins, such as albumin or globulins. Tissue
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bqbinding is the reversible or irreversible attachment of drugs to tissues or organs, such as fat, bone, or brain. Plasma
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bqprotein binding affects drug distribution by limiting the free fraction of drug that can diffuse across capillary walls and reach
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the target site. Plasma protein binding also affects drug elimination by prolonging the half-life and reducing the clearance of
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bqdrugs. Tissue binding affects drug distribution by creating a reservoir or depot for drugs that can maintain a prolonged
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bqeffect or cause toxicity. Tissue binding also affects drug elimination by delaying the elimination of drugs from the body.
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5. What is biotransformation? What are the two main phases of biotransformation? Give an example of each phase and
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explain ho w it changes the chemical structure and activity of drugs.
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- Biotransformation is the process of converting drugs into more polar and less active metabolites that can be excreted by the
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kidneys. The two main phases of biotransformation are phase I and phase II reactions. Phase I reactions are oxidation,
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reduction, or hydrolysis reactions that introduce or expose a functional group on the drug molecule. Phase II reactions are
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conjugation reactions that attach a polar molecule to the functional group on the drug molecule. For example, acetaminophen
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undergoes phase I oxidation by cytochrome P450 enzymes to form N-acetyl-p-benzoquinone imine (NAPQI), which is a toxic
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metabolite that can cause liver damage. NAPQI then undergoes phase II conjugation with glutathione to form a nontoxic
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metabolite that can be excreted in urine.
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6. What are the factors that affect drug metabolism? Give an example of each factor and explain how it influences the rate
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and extent of metabolism.
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