Pharmaceutics Distribution of Drugs Practice Exam

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• How do disease states affecting tissue perfusion alter distribution?
• What features make the small intestine an efficient absorption site?
• To enhance CNS delivery, which modification is commonly pursued?
• Which of the following factors can make a substrate more susceptible to P-gp efflux?
• How would you expect Vd to change for a drug in a patient with ascites?
• Which features characterize CNS capillaries that reduce drug passage?
• Which factor is most likely to increase the apparent volume of distribution for a drug?
• Given constant arterial concentration, what happens to tissue concentration and rate of uptake over time?
• A drug with very high tissue affinity will typically exhibit which combination of plasma concentration and volume of distribution?
• In basic tissue distribution models, which assumption is commonly made about the rate of blood flow through arteries and veins?
• What is the consequence of a displacement interaction at plasma proteins?
• Perfusion-limited distribution is primarily determined by which factor?
• In a two-compartment model, what sequence of phases is observed after intravenous administration?
• How would loading dose be calculated given a target Cp and Vd?
• Thiopental reaches 50% equilibrium in CSF faster than salicylic acid. Thiopental properties:
• If a drug has a Kp value greater than 1 for a given tissue, what does this imply about tissue distribution?
• In a two-compartment pharmacokinetic model, if k12 is much larger than k21, what is the expected distribution pattern?
• During pregnancy, which combination of changes can alter Vd and fu?
• What characteristics determine distribution into bone tissue?
• Which statement best describes how transporter saturation and transporter competition affect distribution rate?
• In a permeability-limited process at the cell membrane, what is the impact on time to reach tissue equilibrium?
• Which statement best explains why thiopental reaches CSF equilibrium faster than salicylic acid?
• Which combination most strongly limits a drug's ability to cross the blood-brain barrier?
• Well perfused tissues take up more drug than poorly perfused tissues. Which option reflects this statement?',
• Edema or fluid overload affects distribution of hydrophilic drugs by:
• In a perfusion-limited, one-compartment model, tissue drug levels are determined mainly by which factor?
• Which statement about oral bioavailability is correct?
• What energy source does P-glycoprotein (P-gp) use to pump substrates?
• Which statement best describes distribution differences between neonates and adults?
• Tissue partitioning can alter concentrations in which compartments, affecting efficacy or toxicity risk?
• If a drug has a volume of distribution of about 5 L, where is it mainly distributed?
• First-pass extraction can occur in which locations?
• A highly lipophilic drug would have which combination of volume of distribution and elimination rate?
• Which factor would increase placental transfer of a drug?
• Caco-2 cells are derived from which tissue?
• If tissue affinity Kp increases while Q and Vt constant, tissue distribution half-life will:
• Describe strategies to enhance CNS distribution for an existing drug.
• P-glycoprotein at the blood-brain barrier primarily causes what effect on CNS exposure?
• How can you distinguish between a perfusion-limited and a permeability-limited distribution in a patient?
• Which relationship best describes the effect of extensive tissue distribution on elimination rate?
• Why does loading dose depend on Vd and target Cp?
• Which statement best explains why higher lipophilicity can influence P-gp interactions?
• Which drugs are more likely limited by permeability rather than perfusion?
• Which of the following would have the shortest time to equilibrium for a lipophilic drug?
• Ion trapping of a basic drug moving from blood to the stomach occurs because the stomach has a lower pH than blood, causing the drug to become ionized and trapped in the stomach. What is the consequence for distribution?
• What does the tissue-to-plasma partition coefficient (Kp) represent?
• The apparent volume of distribution is best described as which of the following?
• Do polar molecules reach equilibrium faster in brain or muscles? why?
• Tissue distribution half-life is expressed as:
• How does plasma protein binding influence the apparent volume of distribution and drug clearance?
• The fractional rate of exit from tissue, denoted kT, is defined as:
• How does a more rapid perfusion rate affect the rate at which drug distribution approaches equilibrium?
• An orally administered drug that is not absorbed from the GI tract will have distribution to which tissue compartments?
• Which is a potential reason for permeability limitation at the cell membrane?
• How does molecular size influence distribution across biological barriers?
• Which factor reduces central nervous system access of a drug besides the properties of the blood-brain barrier itself?
• Which statement best describes displacement interactions on albumin during polypharmacy?
• True or False: Increasing drug concentration will enhance therapeutic effect for a perfusion-limited drug but not for a permeability-limited drug.
• Which pharmacokinetic parameter primarily informs the calculation of a loading dose?
• A high volume of distribution indicates what about drug distribution?
• What is the impact of hematocrit on tissue distribution of plasma-protein bound drugs?
• What would be the distribution of a non-absorbed drug?
• Which parameters predominantly govern the early decline in plasma concentration during the distribution phase in a two-compartment model?
• How does the blood-brain barrier affect distribution into the CNS, and what properties favor CNS penetration?
• Permeability-limited movement at both the capillary and cell membrane would occur in which tissues?
• Which expression correctly represents tissue concentration at equilibrium given arterial input Ca, venous concentration Cv, tissue volume Vt, and partition coefficient Kp?
• Dissolution is defined as which process?
• A drug would leave slowly from tissues with a ____ Kp and a ____Q.
• In a typical 70 kg adult, how many liters of plasma are present (intravascular space)?
• If a drug is very hydrophilic, it will not get past the BBB and will instead show the following relative to lipophilic drugs:
• Which factors can affect transporters at the blood–tissue junction and thereby influence distribution?
• Which characteristic most strongly limits distribution of a drug into bone tissue?
• How does lipophilicity (logP) influence tissue distribution and the volume of distribution?
• At equilibrium, tissue concentration Ct is related to venous concentration Cv by Ct = Kp * Cv. Which of the following expresses Ct in terms Cv?
• What is the unbound (free) fraction fu, and why is it pharmacokinetically important?
• What is the primary purpose of Phase 1 metabolism?
• How do changes in plasma lipid content affect distribution of highly lipophilic drugs?
• Do lipophilic drugs reach equilibrium faster in brain or muscle? why?
• In the simple model, which symbol represents the arterial drug concentration delivering to tissue?
• Placental transfer is influenced by which statement?
• Which statement about Vd is true for drug distribution across species and tissues?
• Which statement best describes placental transfer of drugs?
• True or False: Only ionized drugs typically cross cell membranes.
• What is the effect on apparent Vd when red blood cells act as a reservoir for a drug due to binding?
• Which statement best describes the relationship between absorption and distribution?
• In a two-compartment pharmacokinetic model, what does the alpha (distribution) phase describe?
• In PBPK modeling, what is the role of tissue-specific partition coefficients?
• Which statement about tissue compartments and equilibration with blood is true?
• What property leads to a high tissue partition coefficient (Kp)?
• In perfusion-limited uptake, what's the main controlling factor?
• What do k12, k21, and k10 represent in the two-compartment model?
• For a 70 kg adult, approximately how many liters of total body water are present?
• Which organ is primarily responsible for water reabsorption in the GI tract?
• What is the effect of edema on distribution into the brain?
• What is the primary determinant of the rate at which a drug distributes from the central compartment to the peripheral compartment in a two-compartment model?
• The total volume of fluid compartments accessible to drugs is about how many liters in an adult?
• What is Vdss and how is it used in dosing?
• Which statement best describes the in vitro model used to study intestinal permeability and absorption for orally administered drugs?
• What explains the difference in tissue distribution between thiopental and salicylic acid?
• Which region is the major site for oral absorption?
• What explains non-linear distribution when tissue binding saturates at high drug concentrations?
• Which property most reduces brain exposure for many drugs?
• How can high plasma protein binding influence drug clearance?
• If tissue binding saturates at high concentrations, which outcome is most consistent with the change in unbound fraction (fu) and apparent volume of distribution (Vd)?
• A high tissue-to-plasma partition coefficient (Kp) indicates tissue concentration is:
• What is the clinical significance of a drug having a very large Vd?
• Why might a drug have a higher apparent Vd in obese patients?
• In the two-compartment model, the beta (distribution/elimination) phase is best described as:
• During pregnancy, how is the apparent volume of distribution affected for hydrophilic vs lipophilic drugs?
• Which CNS distribution strategy best aligns with safe enhancement practices for an existing drug?
• In pharmacokinetics, which scenario would most likely increase the rate of distribution to tissues?
• Which of the following is NOT a factor that lowers blood-brain barrier permeability?
• How would a higher affinity drug affect half-life?
• Which organs are most perfused and thus have faster distribution?
• Water-soluble or highly ionized drugs typically show what level of BBB penetration?
• What effect does increased blood flow have on the rate of distribution?
• What is a key limitation of using a one-compartment model to describe drug distribution?
• Which property most readily increases a drug's ability to penetrate the brain?
• In a typical adult, intracellular fluid accounts for approximately what fraction of total body water?
• What is the difference between distribution-limited clearance and perfusion-limited clearance?
• Eyes, fat, and bone have a longer time to reach equilibrium due to which combination of factors?
• A higher Kp suggests high tissue affinity, while a lower Kp suggests greater plasma protein affinity. Complete the statement: A higher Kp indicates high tissue affinity, while a lower Kp indicates greater plasma protein affinity.
• Caco-2 cells are commonly used to test which of the following?
• How does the partition coefficient logP relate to distribution into fat and the Vd?
• Capillary permeability affects the rate of distribution such that...
• Which type of drug can pass the blood-brain barrier despite the barriers?
• What is the practical use of calculating Vd and the distribution phase in designing a loading dose regimen?
• Which expression correctly shows the relationship between tissue and venous concentrations at equilibrium?
• Increasing plasma protein binding of a drug will primarily influence its volume of distribution by...
• Ion trapping can occur when drugs ionize in compartments with different pH. Which statement correctly describes this phenomenon?
• What data are used to compute a loading dose to reach a target plasma concentration quickly?
• If a drug X has a Vd of 1 L/kg in a 60 kg adult, what is the expected total Vd and where would it predominantly be?
• Which statement about central nervous system (CNS) drug distribution is true?
• How does ionization at physiological pH affect drug distribution?
• How does protein binding affinity relate to displacement interactions during polypharmacy?
• Which formula correctly describes a loading dose for a non-intravenous administration given target Cp, Vd, and bioavailability F?
• Which factor would most likely slow tissue distribution?
• Which statement about lipophilicity and tissue distribution is correct?
• Which statement correctly lists the three body water compartments and identifies the majority compartment in a typical 70 kg adult?
• For a typical 70 kg adult, distribution of total body water into plasma, extracellular fluid, and intracellular fluid is:
• The placental barrier is not an absolute barrier; drug transfer depends on drug properties.
• Why can some basic drugs be shifted back from the bloodstream to the stomach after absorption?
• Which statement best describes tissue permeability effects on distribution rate?
• A drug with a high volume of distribution is more likely to be which type of molecule?
• Kp is Ct/Cv. If Kp > 1, what does this indicate about drug distribution?
• What is the distribution-phase half-life, and how is it determined?
• Which statement about the volume of distribution (Vd) is true?
• Which data does physiologically based pharmacokinetic (PBPK) modeling use to predict drug distribution across organs?
• Higher tissue affinity for a drug results in what change to the drug's distribution?
• How can measurement errors in Cp affect the calculation of Vd?
• High plasma protein binding affects CNS distribution by which mechanism?
• How does red blood cell binding affect distribution for drugs that bind to hemoglobin?
• Which drugs have no barrier to distribution via tissue membranes and are solely perfusion limited?
• Kp is defined as Ct/Cv. If Kp > 1, what does this indicate about drug distribution?
• Which drug is given as an example of extensive tissue distribution and a long half-life due to high lipophilicity?
• If a basic drug, after absorption, shifts back into the stomach due to pH differences and becomes ion trapped there, how would the plasma concentration-time curve be affected?
• In pharmacokinetic modeling, there are compartments with instant distribution and slower distribution. Which statement is true?
• Which statement best describes perfusion-limited versus permeability-limited distribution and provides an example?
• Phase 2 metabolism involves which process?
• Explain why the same drug can have different Vd in different species?
• What role do active transporters such as P-glycoprotein play in distribution?
• What factors determine placental transfer of drugs, and how can fetal exposure be assessed?
• Why is tissue partitioning important when predicting drug interactions?
• Which tissue distribution is most often limited by capillary permeability, except when the blood–brain barrier is bypassed or compromised?
• What is the impact of changes in albumin levels on the distribution of acidic drugs?
• A very large Vd is most likely to be associated with which pharmacokinetic consequence?
• Which of the following is an expression for the amount of drug in tissue in terms of tissue concentration and tissue volume?
• How does plasma protein binding interplay with tissue distribution in determining clearance?
• Which factor significantly influences distribution of some drugs into pigmented tissues, affecting volume of distribution?
• Describe how distribution to adipose tissue can affect the pharmacokinetics of a lipophilic drug and its half-life?
• What determines the ultimate brain concentration of a drug after crossing the BBB?
• Which conditions increase BBB permeability, allowing highly lipophilic drugs to cross?
• In a two-compartment model, how do the central and peripheral compartments differ?
• Which statement correctly describes the distribution limitations for polar vs lipophilic drugs?
• Which statement best describes placental transfer?
• Which statement best describes the relationship between tissue perfusion and drug distribution?
• Which alteration would most likely increase a drug's brain exposure?