PK final

Which model of hepatic clearance was used to derive the equation (ClH ~ Q) for high extraction ratio drugs:

A. Well-Stirred Model
B. Parallel Tube Model
C. Distributed Tube Model
D. Dispersion Model
E. Interconnected Tube Model
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Terms in this set (39)
Which model of hepatic clearance was used to derive the equation (ClH ~ Q) for high extraction ratio drugs:

A. Well-Stirred Model
B. Parallel Tube Model
C. Distributed Tube Model
D. Dispersion Model
E. Interconnected Tube Model
A
According to the Hill modification of the Sigmoidal EMAX model, which value of gamma (γ) best indicates that the binding of one drug molecule to its receptor does not influence the binding of subsequent drug molecules?

A. y = 1
B. y > 1
C. y< 1
A
TRUE or FALSE: The dose of drug that generates EMAX may also be used as an estimation of the MTD value of the drug?
A. True
B. False
A
The elimination rate constant of a Drug 32D was measured to be 0.372/h following intravenous injection. Using an infusion rate of 0.40 mg/min, what loading dose should be given at the start of the infusion in order to reach steady-state concentrations as quickly as possible?

A. 64.5 mg
B. 9.11 mg
C. 1.08 mg
D. 0.149 mg
E. 8.93 mg
A
The equation that describes the plasma drug concentration following a single oral administration in a
one-compartment open model at any time post dosing is: Equation #1

Cp = ((F x Ka x Do) / Vd(ka-k)) x (e^-kt - e^-kat)

And the equation for the terminal phase was derived as: Equation #2

Ln Cp - Ln ((F x Ka x Do) / Vd(ka-k)) - kt

During the conversion of Equation 1 into Equation 2, which term in Equation #1 approaches a value of zero drug the terminal phase?
A. e^-kat
B. -kat
C. ka
D. k E. e-kt
A
Please calculate the CSS for a 350 mg oral, anti-diarrheal medication that exhibits a bioavailability of 75% with a volume of distribution of 47 L and a half-life of 6.7 hours, if the medication is given twice per day.
A. 4.52 μg/mL
B. 27.1 μg/mL
C. 225.9 μg/mL
D. 6.78 μg/mL E. 0.069 μg/mL
A
Following a single, oral dose, the plasma drug concentrations at one and five hours post dosing for Drug D20 were 193 μg/mL and 73 μg/mL, respectively. Using the Technique of Superposition, what is the plasma concentration at five hours post dosing, if this drug is dosed once every 4 hours?
A. 266 μg/mL
B. 193 μg/mL
C. 120 μg/mL
D. 73 μg/mL
E. 146 μg/mL
A
Using the trapezoidal rule, the AUC0-∞ for Drug A following a 220 mg iv injection was calculated to be 6389 μg•hr/mL. In the same subjects, the AUC0-∞ for Drug B was calculated to be 5143 μg•hr/mL for a 100 mg iv injection. The relationship between the clearance of Drug A to the clearance of Drug B is:
A. A is cleared faster than B
B. B is cleared faster than A
C. The clearance of A is the same as the clearance of B
D. Cannot be determined as the doses are different
A
A 345 mg intravenous injection of Canceruria A produced an initial plasma concentration of 124 µg/mL. Assuming first-order elimination kinetics and an elimination rate constant of 0.26/hr, how many half-lives will have elapsed by the time that the plasma concentration reaches 7.75 μg/mL?
A. 4 half-lives
B. 1 half-life
C. 2 half-lives
D. 3 half-lives
E. 5 half-lives
A
A double reciprocal plot of albumin binding data for Drug A calculated a Y-intercept of 0.20 and a slope of 1.176 x 10-6 moles/Liter. For Drug B, a similar plot yielded a Y-intercept of 0.20 and a slope of 2.22 x 10-7 moles/Liter. What is the relationship between the concentration of Albumin-Drug A complex [PDA] to the concentration of Albumin-Drug B complex [PDB] in the blood?
A. [PDA] >[PDB]
B. [PDA] <[PDB]
C. [PDA] = [PDB]
B
Immediately following a 430 mg intravenous injection of a new antibiotic, the plasma concentration was measured to be 46 μg/mL. According to the volume of distribution, the drug: A. Remains in the systemic circulation B. Has distributed into the tissue/fat C. Resides mainly in the extracellular compartment D. Has distributed to all body waterAIn vitro experiments showed that the s-enantiomer and the r-enantiomer of Drug A (MW = 438 g/mole) bind to the same site on albumin. The association constant (KA) between the s-enantiomer and albumin is 7.45 x 105 L/mole whereas, the association constant (KA) between the r-enantiomer and albumin is 3.56 x 106 L/mole. Which enantiomer is expected to show the highest concentration in the urine during the first few hour post dosing? A. s-enantiomer B. r-enantiomer C. Concentrations of both enantiomers will be the same D. Concentrations of both enantiomers in the urine will be zeroAAnalysis of the pharmacokinetic curve following the intravenous injection of a new anti-viral medication showed an elimination rate constant of 0.046/hr. What is the expected accumulation ratio if this drug is administered twice per day? A. 2.36 B. 1.74 C. 1.36 D. 3.50 E. No accumulation, drug completely eliminated before next doseAAssuming a hepatic blood flow of 1.3 Liters/min, please calculate the hepatic clearance if the plasma drug concentration entering the liver is 234 μg/mL and the plasma drug concentration leaving the liver is 57 μg/mL. A. 59.0 L/hr B. 0.983 L/hr C. 4.04 L/hr D. 242.4 L/hr E. 3.63 L/hrAWhich rate constant is associated the initial phase of the plasma drug concentration profile for an orally administered drug? A. ka B. k C. k12 D. k21 E. k0AWhich of the following is NOT an assumption when using the equation DL = R/k to calculate the loading dose for an iv infusion dosing regimen? A. A loading dose is injected only after plasma drug levels reach steady state following the start of the infusion B. C0 = Css C. The rate of drug infusion (R) is zero order D. The elimination rate (k) is first-order E. The value of dCP/dt is zero at steady state Question# 17AFor a drug that follows a 2-compartment open model following intravenous injection, the value of the rate constants k12 and k21 are equal: A. When tissue levels of the drug reach its maximum value B. During the distribution phase C. During the elimination phase D. Immediately following injection E. k12 and k21 are never equalABlood samples should be collected and analyzed for drug content immediately following which route of administration to determine an accurate measurement of the Volume of Distribution A. Intravenous injection B. Oral administration C. Intravenous Infusion D. Multiple intravenous injections E. Multiple oral administrationsAPhase 3 clinical trials showed that the oral administration of a 300 mg tablet to healthy subjects generated an AUC value of 5932 μg•hr/mL from the time of administration through 16 hours post dosing, a first-order elimination rate constant of 0.360/hr and a total AUC value of 7135 μg•hr/mL. If the minimum effective concentration is 357.6 μg/mL, should the patient still experience a therapeutic effect even after 16 hours post dosing? A. Yes, plasma drug levels will be sufficient high at 16 hours post dosing to produce a therapeutic effect B. No, plasma drug levels will drop below be sufficient high at 16 hours post dosing to produce a therapeutic effectAFollowing an intravenous injection, please calculate the highest plasma concentration expected for an experimental drug with an initial plasma half-life of 6.8 hours and a zero-order elimination rate constant of 0.352 μg/mL/min. A. 287.2 μg/mL B. 143.6 μg/mL C. 4.79 μg/mL D. 50.4 μg/mL E. 100.8 μg/mLAPhase 1 clinical studies demonstrated that a new anti-psychotic drug generated an initial plasma concentration of 168 μg/mL and exhibited first-order elimination kinetics following an intravenous injection. Analysis of a blood sample collected 3 hours post dosing showed that the plasma concentration had decreased to 126 μg/mL. What is the expected plasma drug concentration after 9 hours post dosing? A. 70.87 μg/mL B. 14 μg/mL C. 4.28 μg/mL D. 1.45 μg/mL E. 32.3 μg/mLAIn general, the pharmacokinetic behavior of an approved drug is provided in Section 12.3 of the Prescribing Information (PI) included in the packaging. Which of the following topics/descriptions is NOT included as part of Section 12.3: A. Animal Toxicology B. Absorption C. Metabolism and Excretion D. Special Populations E. Hepatic ImpairmentAThe consumption of food along with a drug can have all of the following effects EXCEPT: A. Increase the absolute bioavailability to a value greater than 1 B. Decrease the bioavailability of a drug C. Increase the bioavailability of a drug D. Have no effect on the bioavailability of the drug E. Increase the relative bioavailability of the drug to a value greater than 1AWhich statement is FALSE regarding the binding of drugs to blood proteins: A. The association constant KA is dependent only on the concentration of the protein-drug complex B. In general, if given two drugs, the value of KA can be used to predict to which drug a protein will bind to initially. C. A protein can have more than one type of binding site for the same drug D. The variable n refers to the number of identical binding sites for a specific drug on one molecule of proteinATrue or False, The Technique of Superposition can be used to calculate plasma drug concentrations when each dose of the multiple-dosing regimen is different A. True B. FalseBTrue or False, The Technique of Superposition can be used to calculate plasma drug concentrations for a drug given at equal and unequal intervals. A. True B. FalseAIf the pKa of a drug and the pH of the urine are both 7.4, how much drug ends up in the urine? (HINT: LOOK at the equation BEFORE running a calculation) A. 50% B. 25% C. 10% D. 75% E. 100%AThe hepatic intrinsic clearance for a drug was measured to be approximately 58 L/hour. Knowing that the liver blood flow is approximately 1.3 L/min, what characteristic would you assign to this drug: A. Drug undergoes high extraction B. Drug undergoes low extraction C. Drug passes through liver essentially unchanged D. Clearance of this drug by the liver is dependent on the fraction of unbound drug E. Increased liver blood flow will not increase drug removalAThe clearance of an intravenous drug was estimated to be 9.3 L/h and the VD was 42 L. If the initial plasma concentration was 97.3 μg/mL and assuming first-order kinetics, how long will it take for the plasma concentration to reach 1% of its original concentration? A. 20.8 h B. 5.1 h C. 24.7 h D. 15.9 E. 10.25 hATrue or False, albumin binds to acidic drugs while alpha-1-acid glycoprotein binds to basic drugs. A. True B. FalseAThe AUC0-∞ of a new chemotherapy agent following a 125 mg intravenous injection was 7685 µg•hr/mL. Assuming an absolute bioavailability of 82%, what dose of the same drug should be given orally in order to expose the patient to the same level of drug? A. 152.4 mg B. 102.5 mg C. 93.7 mg D. 250.0 mg E. 62.5 mgAIn general, a loading dose is given at the same time that an intravenous infusion is started in order to: A. Reach steady state plasma concentrations as quickly as possible B. Increase the accumulation ratio (R) C. Decrease the elimination rate constant D. Increase plasma levels by saturating metabolizing enzymes E. Decrease the volume of distribution by equilibrating drug levels in the tissuesAWhich of the following statements is FALSE when using the value of VD to predict the in vivo distribution of a drug: A. If VD >400 L, then drug remains bound to plasma proteins B. if VD <10 L, then drug is remains primarily in the systemic circulation C. if 12 <VD <20 L, then drug resides primarily in the extracellular compartment D. if VD ∿ 40 L, then drug distributed in all body water E. if VD >40 L, then drug partitions into tissues, including lipid tissueAThe following data were collected for a new oral antibiotic: AUC0-∞ = 6289 µg•hr/mL AUC0-24h = 5346 µg•hr/mL CP, 0-24h = 130.7 µg/mL Assuming first-order kinetics, calculate the elimination rate constant: A. 0.139/h B. 0.021/h C. 0.024/h D. 1.23/h E. 0.260/hAThe intravenous injection of 275 mg of Drug A produced an initial plasma concentration of 72 μg/mL. Analysis of the plasma sample collected at 3.7 hours post dosing showed that the drug concentration dropped to 36 μg/mL. Assuming first-order kinetics, what is the elimination rate constant for this drug? A. 0.187/h B. 1.85/h C. 7.4/h D. 0.374/h E. 10.65/hADuring the clinical evaluation of 2 new antipsychotic drugs, it was found that the iv injection of 200 mg dose of Drug 21A produced an initial plasma concentration of 84.7 μg/mL and an elimination rate constant of 0.275/h. Whereas, the iv injection of Drug 21B produced an initial plasma concentration of 43.0 μg/mL and an elimination rate constant of 0.154/h. Assuming 1st-order kinetics for both drugs, what is the relationship of the plasma concentration of 21A to the plasma concentration of 21B at 5.6 hours post dosing? A. [21A] = [21B] B. [21A] >[21B] C. [21A] <[21B] D. Both drugs have cleared from the systemic circulation by 5.6 hoursAA pharmaceutical company is evaluating the plasma half-life of a new pain drug that is similar in structure to aspirin. The half-life of this drug immediately following an intravenous 500 mg dose was measured to be 4.2 hours. However, following an intravenous 250 mg dose of the same drug, the half-life was measured to be 2.1 hours. What explanation would you provide to the company as the reason why this drug shows different half-lives? A. The drug likely follows zero-order kinetics B. The drug likely follows first-order kinetics C. The drug likely follows second-order kinetics D. Differences in body weight of the subjects account for the differences E. The amount of drug absorbed from the gastrointestinal tract is dependent on doseAIn the clinic, Drug A, Drug B and Drug C are routinely prescribed to treat hypertension. The CMAX for Drug A is 150 μg/mL and the MTD is 173 μg/mL. Comparatively, the CMAX for Drug B is 146 μg/mL and the MTD is 223 μg/mL, whereas the CMAX for Drug C is 145 μg/mL and the MTD is 312 μg/mL. Based on these data alone, which drug would you recommend to the clinician: A. Drug C B. Drug A C. Drug B D. Cannot be determined without knowing TMAXAWhich of the following drug product characteristics DOES NOT contribute to the absorption process of an oral dosage form: A. Stability of the drug substance B. The rate of release of the drug from the dosage form (e.g. immediate release, extended release) C. The type of dosage form that is administered (tablet, capsule, solution, suspension) D. Disintegration rate of the dosage form E. Solubilization rate of the drug substanceA