Pharmacokinetics and Drug Design (PC 710)
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Questions and Answers

What does the 'A' in the ADME acronym stand for?

  • Adjuvant
  • Allocation
  • Absorption (correct)
  • Attenuation

Which of the following processes occurs after absorption in the ADME sequence?

  • Excretion
  • Metabolism (correct)
  • Synthesis
  • Activation

In the context of drug disposition, what does the term 'distribution' refer to?

  • The initial uptake of drugs
  • The conversion of drugs into metabolites
  • The movement of drugs throughout the body (correct)
  • The elimination of drugs from the body

Which step in the ADME process primarily involves the liver's processing of substances?

<p>Metabolism (C)</p> Signup and view all the answers

Which component of ADME is most directly concerned with how drugs leave the body?

<p>Excretion (C)</p> Signup and view all the answers

What is the primary focus of the lecture on Drug Design (PC 710)?

<p>Effects of physicochemical properties on pharmacokinetics (C)</p> Signup and view all the answers

Which factors are likely to affect the pharmacokinetic profile of a drug?

<p>Molecular weight and solubility (B)</p> Signup and view all the answers

Which aspect is most directly impacted by the physicochemical properties of a drug?

<p>Absorption, distribution, metabolism, and excretion (C)</p> Signup and view all the answers

Which of the following is NOT a classical physicochemical property considered in drug design?

<p>Brand loyalty (B)</p> Signup and view all the answers

How do physicochemical properties influence drug solubility?

<p>They determine the lipid-water partitioning of the drug. (A)</p> Signup and view all the answers

What is the maximum molecular mass for a compound to meet the specified criteria?

<p>500 (C)</p> Signup and view all the answers

What is the highest allowable value for log P in the criteria given?

<p>5 (B)</p> Signup and view all the answers

How many hydrogen bond donors can a compound have at maximum according to the criteria?

<p>5 (A)</p> Signup and view all the answers

Which of the following statements about the criteria is correct?

<p>No more than 5 hydrogen bond donors are permitted. (B)</p> Signup and view all the answers

Which characteristic does NOT adhere to the given criteria for a compound?

<p>Hydrogen bond donors totaling 6 (A)</p> Signup and view all the answers

What is essential for a drug to effectively bind to its receptor?

<p>Specific physiochemical properties (C)</p> Signup and view all the answers

Which physiochemical property is least likely to affect a drug's biological activity?

<p>Color of the drug (A)</p> Signup and view all the answers

How does the solubility of a drug influence its action?

<p>It affects its distribution in the body (C)</p> Signup and view all the answers

If a drug exhibits high ionization at physiological pH, what is the likely consequence?

<p>Decreased ability to bind to receptors (A)</p> Signup and view all the answers

What role does molecular weight play in drug design?

<p>It helps determine the route of administration (D)</p> Signup and view all the answers

What is the primary mechanism of passive diffusion?

<p>Movement along the concentration gradient (A)</p> Signup and view all the answers

Which statement best describes active transport?

<p>It requires energy to move substances against the concentration gradient. (D)</p> Signup and view all the answers

In passive diffusion, how does the concentration gradient affect drug movement?

<p>Drugs move from high to low concentration. (D)</p> Signup and view all the answers

What is necessary for active transport to occur?

<p>Energy input from ATP or another source. (C)</p> Signup and view all the answers

Which of the following is NOT true regarding passive diffusion?

<p>It requires energy to occur. (A)</p> Signup and view all the answers

What does absorption involve in the context of drug administration?

<p>Transportation of molecules across cell membranes (C)</p> Signup and view all the answers

Which type of injection involves depositing a drug directly into the skin layers?

<p>Intradermal injection (D)</p> Signup and view all the answers

Which of the following best describes an intraperitoneal injection?

<p>Injection into the peritoneal cavity (B)</p> Signup and view all the answers

What is a common purpose of drug absorption in the body?

<p>To facilitate the therapeutic effects of a drug (A)</p> Signup and view all the answers

Which statement accurately describes the absorption process?

<p>It requires the drug to be in a solution form. (C)</p> Signup and view all the answers

Flashcards

Pharmacokinetic (PK) Profile

The study of how physical and chemical properties of a drug influence its absorption, distribution, metabolism, and excretion (ADME) in the body.

Physicochemical Properties

Properties of a drug that influence its behavior in the body. These include things like size, shape, charge, and solubility.

Absorption

The process by which a drug enters the bloodstream from its site of administration.

Distribution

The process by which a drug is transported throughout the body to its target site.

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Metabolism

The process by which the body breaks down a drug into metabolites.

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Elimination

The rate at which a drug is eliminated from the body.

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Potency

A measure of the amount of drug required to produce a therapeutic effect.

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Drug Metabolism

The process where a drug is broken down into smaller, inactive molecules by the body.

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Excretion

The removal of a drug and its metabolites from the body.

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Pharmacokinetics

The study of how the body affects a drug.

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Molecular Mass

The total combined weight of all atoms in a molecule, expressed in atomic mass units (amu). It's usually less than 500 amu for good oral drug absorption.

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Log P

A measure of how well a drug dissolves in lipids (fats) compared to water. A log P value of less than 5 indicates a good balance between water solubility and lipid solubility, allowing the drug to move through both environments in the body.

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Hydrogen-Bond Donors

A measure of how many times a drug molecule can form bonds with water molecules. A smaller number of donors indicates a drug with less tendency to interact with water molecules, which is favorable for oral absorption.

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Drug Physicochemical Properties

These are structural features that dictate a drug's ability to be absorbed into the bloodstream. They play a crucial role in determining how well a drug works in the body.

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Drug Characteristics

These properties are key for a drug to reach its target and exert its effect. They're related to a drug's size, shape, charge, and solubility.

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Passive Diffusion

Movement of a drug from an area of high concentration to an area of low concentration. This doesn't require energy.

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Active Transport

Movement of a drug against its concentration gradient, from low to high concentration. This requires energy.

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Drug Distribution

The way a drug moves around the body after it's been absorbed.

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Drug Elimination

The removal of a drug and its metabolites from the body, usually through urine, feces, or breath.

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Drug Absorption

The movement of molecules across cell membranes, enabling drugs to enter the bloodstream or other body tissues.

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Intraperitoneal Injection (IP)

A type of drug absorption where the drug is injected directly into the space surrounding the internal organs.

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Intradermal Injection

A type of drug absorption where the drug is injected into the skin's upper layer.

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Intravenous Injection (IV)

A type of drug absorption where the drug is injected directly into a vein.

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Intramuscular Injection (IM)

A type of drug absorption where the drug is injected into a muscle.

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Study Notes

Drug Design (PC 710) Lecture

  • The lecture covered the effect of physicochemical properties on the pharmacokinetic profile of drugs.
  • Physicochemical properties are crucial for a drug to bind to its receptor and exert its biological activity.
  • These properties influence how a drug reaches its site of action, its affinity to the target, and overall activity.
  • Factors affecting drug structure and physicochemical properties include pKa, solubility, polarity, and steric factors (bulkiness).
  • Lipinski's rule of five determines the likelihood of a drug being orally bioavailable. This includes:
    • Molecular mass less than 500
    • Log P not greater than 5
    • No more than 5 hydrogen bond donors
    • No more than 10 hydrogen bond acceptors
    • 10 or fewer rotatable bonds
    • Polar surface area (PSA) not greater than 140 Ã…2
  • In-silico prediction tools (SwissADME.com and Molinspiron.com) are available to predict oral bioavailability and pharmacokinetic parameters.
  • Physicochemical properties affect the drug's absorption, distribution, metabolism, and excretion (ADME).
  • Absorption is the transportation of molecules across cell membranes (Passive, active, convective).
    • Examples of absorption factors include the dissolution/solubility rate, dissociation constant (pKa), and partition coefficient (Log P).
    • Particle size and pH of the medium affect the solubility of drugs.
      • Smaller particle size leads to increased surface area and faster solubility.
      • pH affects the ionization of acids or bases impacting their absorption.
  • Distribution involves the drug traveling to the target organ.
    • Plasma protein binding can act as a storage site, preventing drug activity.
    • Neutral fats and adipose tissue can also store drugs.
    • Factors influencing deposition in adipose tissue include partition coefficient (Log P).
  • Metabolism: The lecture emphasized referring to a separate metabolism lecture for further details on phases I and II.
  • Excretion: The process of removing metabolic waste products from the body, occurs in the lungs, liver, kidneys, and skin.

Drug Absorption Factors

  • Dissolution/Solubility Rate: crucial step; the rate at which the drug dissolves in the gastrointestinal (GI) fluids.
  • Dissociation Constant (pKa): affects the ionization state of a drug (acids/bases) and its absorption based on the pH of the GI tract.
  • Partition Coefficient (Log P): measures a drug's lipophilicity (lipid-water solubility). A higher log P value indicates better absorption.
    • Higher Log P values indicate increased lipid solubility, promoting absorption
  • Example: Spironolactone and Griseofulvin are formulated as micronized capsules to improve their bioavailability, thereby impacting these properties

Absorption: pKa

  • For weak acids: pKa = pH + log [unionized acid / ionized acid].
  • For weak bases: pKa = pH + log [unionized base / ionized base].
  • Drugs are more easily absorbed in their unionized state. This state depends on the pH of the absorption site.
    • Drugs are better absorbed in their unionized forms in areas where their pKa is higher than the pH.
    • Drugs are better absorbed in their ionized forms in areas where their pKa is lower than the pH.

Absorption: Log P

  • log P = log ([organic phase concentration] / [aqueous phase concentration])
  • A higher log P value indicates better lipid solubility and better absorption.

Modifying Drug Properties to Improve Absorption

  • Changing a drug's lipophilicity or introducing hydrophobic groups can improve its absorption.
  • Hydrophobicity constants (Ï€) are available in tables for modifying drugs.

Distribution to Target Organ

  • Discusses factors impacting a drug's distribution to the target organ, including plasma protein binding, neutral fat deposition in adipose tissue.

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Drug Design (PC 710) Lecture Notes PDF

Description

Test your knowledge on pharmacokinetics and key concepts in drug design with this quiz. Topics include the ADME process, factors affecting pharmacokinetics, and physicochemical properties of drugs. Ideal for students studying pharmacology or related fields.

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