session 16 notes

1. Oral absorption is determined by how much drug cross the cell membrane in the GI tract. 

 

True

 

False

False

Which of the following absorption mechanisms need transporters? (choose all correct answers)

 

Passive diffusion

 

Active transport

 

Facilitated transport

Active transport

 

Facilitated transport

Fick’s First Law describes the rate of passive diffusion. What are the parameters in the simplified Fick’s First Law? (Choose all correct answers)

 

Permeability coefficient

 

Drug particle size

 

Drug concentration in the absorption site (e.g. in small intestine)

 

Saturated drug concentration

Permeability coefficient

Drug concentration in the absorption site (e.g. in small intestine)

Permeability coefficient is related to: (choose all correct answers)

 

Area of the absorbing membrane

 

Thickness of the absorbing membrane

 

Partition coefficient

 

Diffusion coefficient

Area of the absorbing membrane

 

Thickness of the absorbing membrane

 

Partition coefficient

 

Diffusion coefficient

Permeability coefficient describes the process of passive diffusion in which a molecule is absorbed through the GI tract, while partition coefficient is a measure of how permeable of a drug to the cell membrane.

 

True

 

False

True

According to Fick’s First Law, the rate of diffusion across a membrane is primarily governed by:

 

The pH of the surrounding fluid

 

The temperature of the environment

 

The electrical charge of the molecules

 

The concentration gradient

The concentration gradient

Lipophilicity is crucial for drug absorption because:

 

It determines the ability of the drug to cross lipid membranes

 

It enhances the solubility of the drug in water

 

It increases the drug's molecular weight

 

It reduces the rate of drug metabolism

It determines the ability of the drug to cross lipid membranes

Which of the following mechanisms of drug absorption involves the movement of molecules against a concentration gradient and requires energy?

 

Paracellular transport

 

Active transport

 

Facilitated diffusion

 

Passive diffusion

 

Active transport

Which of the following statements about the pH-partition hypothesis is correct?

 

The hypothesis only applies to acidic drugs

 

Ionized drugs cross membranes more easily than un-ionized drugs

 

Un-ionized drugs are absorbed more efficiently than ionized drugs

 

It predicts the solubility of drugs in the stomach

Un-ionized drugs are absorbed more efficiently than ionized drugs

The partition coefficient is a measure of a drug's:

 

Stability in the gastrointestinal tract

 

Distribution between lipid and aqueous phases

 

Solubility in water

 

Ability to ionize in solution

Distribution between lipid and aqueous phases

What is the primary role of biopharmaceutics?

 

To create new pharmaceutical formulations

 

To conduct clinical trials for new drugs

 

To understand the relationship between the physical, chemical, and biological sciences as they apply to drugs

 

To manage drug production processes

To understand the relationship between the physical, chemical, and biological sciences as they apply to drugs

What is the process by which a drug is transferred from the gastrointestinal tract to the circulating system (blood)?

 

Absorption

 

Metabolism

 

Distribution

 

Excretion

Absorption

What does Fick's First Law describe?

 

The passive diffusion of drug molecules across a membrane at steady-state

 

The interaction between drugs and excipients

 

The absorption of drugs in the stomach

 

The rate of drug metabolism in the liver

The passive diffusion of drug molecules across a membrane at steady-state

Which of the following factors does NOT directly influence a drug's absorption through the gastrointestinal tract?

 

Lipid solubility

 

Molecular size

 

Degree of ionization

 

Taste of the drug

Taste of the drug

How does the pH of the gastrointestinal (GI) tract influence drug absorption?

 

It does not influence drug absorption

 

It only affects drugs that are weak acids

 

It primarily impacts the drug's taste and stability

 

It affects the solubility and ionization of drugs, which in turn influences absorption

It affects the solubility and ionization of drugs, which in turn influences absorption