PBPK Models and Oral Absorption Pharmacokinetics
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Questions and Answers

What is the primary role of enterocytes in the intestinal lining?

  • To absorb nutrients (correct)
  • To transport waste
  • To produce digestive enzymes
  • To facilitate blood circulation

    • Which pathway carries cumulative amounts of substances absorbed from the intestines to the liver?

  • Portal vein (correct)
  • Lymphatic system
  • Hepatic artery
  • Pulmonary circulation

    • In pharmacokinetics, what does the cumulative amount entering systemic circulation refer to?

  • Volume of bile produced by the liver
  • Total nutrients absorbed by enterocytes
  • Amount of drug reaching the bloodstream after absorption (correct)
  • Rate of waste elimination from the body

    • What does the color coding represent in the absorption and circulation process described?

    <p>Different routes of absorption and circulation</p> Signup and view all the answers

    What is typically characterized by the interactions within enterocytes and their environment?

    <p>Pharmacokinetics</p> Signup and view all the answers

    What was one of the main challenges of the early PBPK model?

    <p>Limited computer capabilities</p> Signup and view all the answers

    Which of the following models is primarily related to oral absorption kinetics?

    <p>Loo–Riegelman model</p> Signup and view all the answers

    How is the transit process in pharmacokinetic models represented?

    <p>By differential equations</p> Signup and view all the answers

    What is indicated by the terms ka and k in pharmacokinetics?

    <p>Rate of absorption and rate of elimination</p> Signup and view all the answers

    What contributed to the recent acceleration of PBPK development?

    <p>Improved in silico techniques</p> Signup and view all the answers

    Which issue hindered the development of the PBPK approach for many years?

    <p>Lack of advanced in vitro data</p> Signup and view all the answers

    Which methodological direction is NOT typically used in pharmacokinetic absorption studies?

    <p>Intravenous administration</p> Signup and view all the answers

    Which aspect of PBPK models primarily relates to drug transit?

    <p>Compartmentalization</p> Signup and view all the answers

    What is the solubility of Ketoprofen in mg/mL as indicated?

    <p>17.29 mg/mL</p> Signup and view all the answers

    Which concentration of Ketoprofen is listed among the values?

    <p>2.0 µg/mL</p> Signup and view all the answers

    What percentage of the Total SC for Ketoprofen is noted?

    <p>99.9%</p> Signup and view all the answers

    Which of the following values corresponds to the AmtPV for Ketoprofen?

    <p>0.9792</p> Signup and view all the answers

    What is the Total SC value for Ketoprofen?

    <p>99.9%</p> Signup and view all the answers

    What is the AmtAbs value for Ketoprofen?

    <p>35.3 mg</p> Signup and view all the answers

    Among the following, which is NOT a concentration listed for Ketoprofen?

    <p>2.5 µg/mL</p> Signup and view all the answers

    In what unit is the AmtDiss for Ketoprofen measured?

    <p>mg</p> Signup and view all the answers

    What is indicated as the amount of Ketoprofen in mg?

    <p>4.39 mg</p> Signup and view all the answers

    What is the total amount referred to under AmtDiss for Ketoprofen?

    <p>60 mg</p> Signup and view all the answers

    What is the percentage concentration of Atenolol mentioned?

    <p>37.9%</p> Signup and view all the answers

    What is the mass in mg of the Atenolol that has a solubility of 0.0025 mg/mL?

    <p>0.367 mg</p> Signup and view all the answers

    What is the logD value provided in the content?

    <p>9.33</p> Signup and view all the answers

    Which formulation types are mentioned for Atenolol?

    <p>Suspension and tablet</p> Signup and view all the answers

    Which mass value correlates with an absorption quantity of 0.2?

    <p>0.3 mg</p> Signup and view all the answers

    What percentage correlates with a value marked as 3.8%?

    <p>Concentration</p> Signup and view all the answers

    What is the total solid content indicated in the values?

    <p>100 mg</p> Signup and view all the answers

    What value is represented as dDB in the formulas given?

    <p>5.761</p> Signup and view all the answers

    Which value is indicative of a high logD in the document?

    <p>16.2</p> Signup and view all the answers

    What is the likely interpretation of a solubility level of 0.367 mg/mL?

    <p>It indicates moderate solubility.</p> Signup and view all the answers

    How is the absorption quantity quantified in the data?

    <p>Amount per Volume</p> Signup and view all the answers

    What is the total SC value provided in the data?

    <p>100</p> Signup and view all the answers

    What does the solubility of 0.0025 mg/mL suggest?

    <p>It suggests poor solubility.</p> Signup and view all the answers

    What percentage represents Total SC for Metoprolol?

    <p>93.0%</p> Signup and view all the answers

    Which order of reaction can the solubility of Metoprolol potentially exhibit?

    <p>First-order</p> Signup and view all the answers

    What is the solubility of Metoprolol in mg/mL?

    <p>0.0064 mg/mL</p> Signup and view all the answers

    Which value represents the maximum amount in mg for Metoprolol indicated in the data?

    <p>150 mg</p> Signup and view all the answers

    What is the AmtAbs for Metoprolol?

    <p>93%</p> Signup and view all the answers

    Which concentration in µg/mL is represented in the data?

    <p>150 µg/mL</p> Signup and view all the answers

    What value corresponds to AmtDiss for the given substance?

    <p>3</p> Signup and view all the answers

    Which of the following is NOT a concentration mentioned in the data?

    <p>35.9 µg/mL</p> Signup and view all the answers

    What can the rate and extent of dissolution for Metoprolol depend on?

    <p>Physicochemical property differences</p> Signup and view all the answers

    What does AmtPV likely refer to in dissolution studies?

    <p>Amount per volume</p> Signup and view all the answers

    What is a plausible unit for expressing solubility?

    <p>mg/mL</p> Signup and view all the answers

    Which of the following values is likely to increase the dissolution performance?

    <p>Higher solubility values</p> Signup and view all the answers

    Which statement regarding solubility for Metoprolol is true?

    <p>It exhibits poor solubility.</p> Signup and view all the answers

    Which of the following reflects the Absorption amount?

    <p>AmtAbs</p> Signup and view all the answers

    What characteristic is NOT typically related to the physicochemical properties of a substance?

    <p>Amount of powder</p> Signup and view all the answers

    Study Notes

    PBPK Models

    • The first pharmaco kinetic model using the Loo–Riegelman method was a PBPK model (Teorell, 1937), however, its computation faced challenges due to the lack of computers and underdeveloped in vitro techniques.
    • PBPK model development has accelerated in recent years due to advances in computer science and availability of in vitro systems used as surrogates for in vivo reactions.
    • This PBPK approach relies on in vitro and in silico data, which was not available until recent years when computing and in vitro techniques evolved significantly.
    • In silico refers to computer-based models.

    Pharmacokinetics of Oral Absorption

    • Oral dosing is the primary focus of the text, though the concepts can be extrapolated to extravascular routes.
    • Two methodologies can be used to study the kinetics of absorption:
      • Building pharmacokinetic models based on direction of drug transit among compartments.
      • Each transit process can be expressed using a differential equation.

    Understanding Oral Absorption

    • The text discusses how oral absorption can be characterised as either a first-order or a zero-order input process.
    • Various factors influence the rate and extent of absorption.

    Model Visualization

    • The text uses a visual representation to demonstrate the process of drug absorption.
    • The visualization shows the cumulative amount of dissolved drug (AmtDiss), the cumulative amount entering the portal vein (AmtPV), and the cumulative amount entering systemic circulation (Total SC).

    Example Drugs for Model

    • Metoprolol is an example of a drug with a high rate of absorption (93% bioavailability) and a first-order input process.
    • Ketoprofen is an example of a drug with a high rate of absorption (99.9% bioavailability) and a first-order input process.

    Atenolol Properties

    • Atenolol is a beta-blocker drug, commonly available in multiple formulations including solutions, suspensions, tablets, and capsules.
    • It has a solubility of 0.0025 mg/mL, a logD of 9.33, and a pKa of 9.33.
    • The total systemic clearance of atenolol is 37.9% with an absorption rate constant of 0.3. It's estimated that the amount absorbed is 3 mg.
    • Atenolol exhibits a concentration in the range of 5.761 x 103 µg/mL, with a volume of distribution of 16.2 L.
    • Atenolol has a mass of 8.2 mg and is available in various dosage forms including controlled release (CR) formulations, such as enteric-coated tablets and capsules.
    • Atenolol has a bioavailability of 37.9% and undergoes a constant elimination rate of 8.5% per hour.
    • Atenolol is eliminated in the urine.
    • The maximum amount of atenolol in the body occurs at 40 mg, with a corresponding time of 10 hours.
    • The blood concentration of atenolol decreases over time with a half-life of approximately 6 hours.

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    Pharmacokinetics of Oral Absorption PDF

    Description

    Explore the fundamentals of Physiologically Based Pharmacokinetic (PBPK) models and their application in studying oral absorption. This quiz covers the historical challenges in model development and the evolution of techniques in pharmacokinetics. Test your knowledge on how in vitro and in silico data contribute to understanding drug absorption.

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