Question 1

All of the following about passive absorption is true EXCEPT:

Accepted Answer

Passive absorption is not saturable because it does not involve carriers or transport proteins, and it relies solely on the concentration gradient.

Question 2

All of the following are general mechanisms of drug permeation Except

Accepted Answer

Aqueous hydrolysis is not a general mechanism of drug permeation.

Question 3

The following factor(s) influencing drug absorption:

Accepted Answer

All the listed factors (blood flow to the absorption site, total surface area available for absorption, and contact time at the absorption surface) influence drug absorption.

Question 4

First pass effect is:

Accepted Answer

The first pass effect refers to the initial metabolism of a drug in the liver, reducing its concentration before it reaches systemic circulation after oral administration.

Question 5

What does the term "bioavailability" mean?

Accepted Answer

Bioavailability refers to the proportion of a drug that enters the systemic circulation when introduced into the body and is available for activity, regardless of the route of administration.

Question 6

Factor(s) that influence bioavailability of drugs:

Accepted Answer

All the listed factors (A, B, C, D) influence the bioavailability of drugs by affecting absorption, metabolism, and stability.

Question 7

What is the proportion of nonionized form of week base (pka = 9.4)when put in a media ( pH = 7.4 )

Accepted Answer

The Henderson-Hasselbalch equation can be used to calculate the proportion of nonionized form of a weak base:```pH = pKa + log([A-]/[HA])```where:* pH is the pH of the solution* pKa is the acid dissociation constant of the weak base* [A-] is the concentration of the anion form of the weak base* [HA] is the concentration of the nonionized form of the weak baseIn this case, the pH of the solution is 7.4 and the pKa of the weak base is 9.4. Substituting these values into the Henderson-Hasselbalch equation, we get:```7.4 = 9.4 + log([A-]/[HA])```Solving for [A-]/[HA], we get:```[A-]/[HA] = 10^(7.4 - 9.4) = 0.01```This means that the proportion of nonionized form of the weak base is 0.01, or 1%.

Question 8

Which of the following acids has the highest degree of ionization in an aqueous solution?

Accepted Answer

The degree of ionization of an acid in solution is inversely related to its pKa value. The lower the pKa, the stronger the acid and the higher its degree of ionization. Aspirin, with the lowest pKa of 3.5, has the highest degree of ionization among the given options.

Question 9

The excretion of a weakly acidic drug generally is more rapid in alkaline urine than in acidic urine. This process occurs because

Accepted Answer

A weak acid in alkaline media will exist primarily in its ionized form, which is less lipophilic and cannot easily cross cell membranes to be reabsorbed, leading to more rapid excretion.

Question 10

Passive diffusion doesn't depend on,

Accepted Answer

Passive diffusion does not require transporters; it relies on the concentration gradient, permeability, and thickness of the membrane.

Question 11

The following factor(s) determine drug distribution:

Accepted Answer

All of the factors listed (blood flow, capillary permeability, and drug structure) play a role in determining drug distribution.

Question 12

Most of the drugs are distributed homogeneously

Accepted Answer

Drugs are often distributed heterogeneously in the body due to factors like blood flow, tissue permeability, and binding to proteins or tissues, leading to varying concentrations in different areas.

Question 13

The volume of distribution for a drug that is completely retained in the vascular compartment would be.

Accepted Answer

The answer of The volume of distribution for a drug...

Question 14

A patient is treated with a Drug A, which has a high affinity for Albumin and is administered in amount that don't exceed the binding capacity of Albumin. A second drug B also has a high affinity for albumin but is administered in amounts that are 100 time the binding capacity of albumin. What happens after administration of Drug B?

Accepted Answer

The answer of A patient is treated with a Drug...

Question 15

All of the following factors may increase the volume of distribution EXCEPT:

Accepted Answer

Blood tissue barriers can limit the distribution of a drug, thereby decreasing the volume of distribution.

Question 16

All of the following statements related to the binding of drugs by plasma proteins are correct EXCEPT?

Accepted Answer

Bound drug is not pharmacologically active; it is the unbound (free) drug that is active and able to exert a therapeutic effect.

Question 17

All of the following about free drugs (unbound drags) in plasma are correct EXCEPT:

Accepted Answer

Highly bound drugs (98% bound) have minimal drug-drug interactions with other drugs through displacement from binding sites on plasma protein.

Question 18

A patient with an edema would have an increased volume of distribution if

Accepted Answer

Edema increases the volume of extracellular fluid, which can increase the volume of distribution for hydrophilic drugs that distribute primarily in the extracellular fluid.

Question 19

What would be the expected distribution of Digoxin in the case of odema?

Accepted Answer

The answer of What would be the expected distribution of...

Question 20

What is the reason of complicated penetration of some drugs through brainblood barrier?

Accepted Answer

The answer of What is the reason of complicated penetration...

Quiz 6: Chapter 6: Pharmacokinetics and Drug Absorption: Understanding Drug Permeation, Distribution, and Elimination