p.13
Drug Transport Mechanisms
What is the relationship between concentration and transport in carrier-mediated transport?
As concentration increases, transport also increases until a maximum is reached.
p.18
Cell Membrane Structure
What is a characteristic of channel-mediated transport regarding cell membrane layers?
There is no penetration of the layers of the cell membrane.
p.11
Passive Diffusion Characteristics
What does membrane thickness refer to?
The distance a molecule has to traverse from the absorption surface to a blood capillary.
p.11
Passive Diffusion Characteristics
What is the relationship between membrane thickness (MT) and absorption?
Increased MT leads to decreased absorption, while decreased MT leads to increased absorption.
p.13
Drug Transport Mechanisms
What limits the transport in carrier-mediated transport?
Saturation of the transport mechanism.
p.15
Active Transport Mechanisms
What do efflux transporters do?
They transport molecules out of the cell.
p.8
Active Transport Mechanisms
What is the function of a substrate in drug transport?
A substrate is pushed out of the cell by a transporter.
p.4
Hydrophilic vs. Hydrophobic Properties
What is the n-octanol/water partition coefficient used for?
It is a common measure of lipophilicity.
p.15
Active Transport Mechanisms
What is another name for active transport mechanisms?
Concentrating Transporters.
p.8
Passive Diffusion Characteristics
What is the relationship between drug size and lipophilicity to permeability?
Larger and more lipophilic drugs generally have higher permeability.
p.17
Active Transport Mechanisms
What are the three main types of active transport mechanisms?
Pumps, Concentrating Transporters, and Endocytosis.
p.17
Endocytosis Types and Functions
What is pinocytosis?
Pinocytic uptake in which molecules enter the cell as part of the fluid phase.
p.17
Active Transport Mechanisms
What is required for molecules to enter circulation through active transport?
They need to pass through several membranes.
p.12
Drug Transport Mechanisms
What is carrier-mediated transport?
A process that involves proteins to facilitate the movement of substances across a membrane.
p.4
Facilitated Diffusion and Carrier Proteins
How do carrier proteins assist in drug transport?
They help facilitate the movement of drugs across membranes.
p.14
Passive Diffusion Characteristics
Does passive diffusion require energy?
No, it does not use energy (ATP).
p.7
Passive Diffusion Characteristics
What is the formula for the net rate of permeation in passive diffusion?
Net rate of permeation = P × SA × (Cu1 - Cu2)
p.16
Active Transport Mechanisms
What type of energy is typically used in active transport?
ATP (adenosine triphosphate).
p.16
Active Transport Mechanisms
Can active transport occur without the presence of a membrane protein?
No, it typically requires specific carrier proteins or pumps.
p.8
Passive Diffusion Characteristics
How does permeability relate to drug transport?
Permeability is crucial for the effective transport of drugs across cell membranes.
p.17
Endocytosis Types and Functions
What characterizes clathrin-mediated endocytosis?
Large extracellular molecules have receptors on the cell.
p.14
Active Transport Mechanisms
What is the difference between influx and efflux transport?
Influx is the uptake of substances into the cell, while efflux is the outward transport of substances from the cell.
p.5
Active Transport Mechanisms
What is the driving force for active transport?
Against the concentration gradient.
p.7
Passive Diffusion Characteristics
How does drug size affect permeability?
Larger drug size generally decreases permeability.
p.6
Drug Transport Mechanisms
What are the two main pathways for drug transport across membranes?
Paracellular and transcellular pathways.
p.18
Drug Transport Mechanisms
What can pass through channel-mediated transport?
Anything could go in or out, including water.
p.14
Passive Diffusion Characteristics
What is passive diffusion?
The movement of water-soluble molecules or drugs across the plasma membrane without the use of energy.
p.1
Drug Transport Mechanisms
What is the title of the course offered at Saint Louis University?
Biopharmaceutics and Pharmacokinetics.
p.5
Active Transport Mechanisms
What type of molecules are transported via active transport?
Lipid insoluble molecules; high molecular weight.
p.5
Facilitated Diffusion and Carrier Proteins
What happens to co-transported molecules in facilitated diffusion?
They can compete and inhibit each other.
p.11
Passive Diffusion Characteristics
What is the typical thickness range for cell membranes?
0.005 to 0.01 micrometers.
p.13
Drug Transport Mechanisms
What is meant by 'transport maximum' in carrier-mediated transport?
The maximum rate of transport that can be achieved when all carriers are saturated.
p.15
Active Transport Mechanisms
How does active transport differ from passive transport?
Active transport requires energy, while passive transport does not.
p.1
Drug Transport Mechanisms
Who compiled the course material for PHARM 314?
Cristopherson P. Mata, RPh, MS Pharm.
p.4
Drug Transport Mechanisms
What is paracellular drug transport?
The passage of drug through aqueous channels.
p.3
Drug Distribution and Metabolism
What is metabolism in the context of drug action?
Biotransformation of drugs in the body.
p.12
Drug Transport Mechanisms
What role do proteins play in carrier-mediated transport?
They help move substances across the membrane.
p.7
Passive Diffusion Characteristics
What is the natural tendency of molecules in passive diffusion?
To move down a concentration gradient.
p.9
Passive Diffusion Characteristics
What are the key drug properties that determine passive permeability?
Drug size, lipophilicity, and charge/degree of ionization.
p.9
Passive Diffusion Characteristics
How does urine acidification affect drug absorption?
It can enhance the absorption of weak bases by creating a more favorable environment for their unionized form.
p.17
Endocytosis Types and Functions
What is phagocytosis?
Adsorptive or phagocytic uptake of particles that have been bound to the cell membrane surface.
p.3
Drug Absorption Mechanisms
What is the process of drug absorption?
Drugs pass through the gut wall.
p.12
Drug Transport Mechanisms
What are the two main types of carrier-mediated transport?
Facilitated diffusion and active transport.
p.2
Hydrophilic vs. Hydrophobic Properties
What is the solubility of hydrophobic substances in water?
They are not soluble in water.
p.14
Passive Diffusion Characteristics
What is the role of kinetic energy in passive diffusion?
Kinetic energy drives the movement of molecules across the membrane.
p.7
Passive Diffusion Characteristics
What is the relationship between lipophilicity and drug absorption?
Increased lipophilicity leads to increased absorption.
p.13
Drug Transport Mechanisms
What is a characteristic of carrier-mediated transport regarding specificity?
It is specific to certain molecules.
p.1
Drug Transport Mechanisms
What is the focus of UNIT 4 in the PHARM 314 course?
Drug Transport Mechanisms.
p.2
Cell Membrane Structure
What are the main components of the cell membrane?
Phospholipids, cholesterol, and proteins.
p.14
Facilitated Diffusion and Carrier Proteins
What are aquaporins?
Membrane proteins that facilitate the passive transport of water across cell membranes.
p.14
Facilitated Diffusion and Carrier Proteins
Is facilitated diffusion saturable?
No, it is not saturable and occurs until equilibrium is reached.
p.5
Drug Transport Mechanisms
What is the most common transport mechanism for drugs?
Most drugs use passive diffusion.
p.15
Active Transport Mechanisms
What are influx transporters responsible for?
They allow molecules to enter the cell.
p.8
Drug Transport Mechanisms
What role do pumps play in drug transport in the brain?
Pumps transport drugs out of the brain, affecting drug permeability.
p.4
Hydrophilic vs. Hydrophobic Properties
What do hydrophilic and hydrophobic refer to?
Hydrophilic refers to substances that attract water, while hydrophobic refers to substances that repel water.
p.4
Hydrophilic vs. Hydrophobic Properties
What does a higher partition coefficient indicate?
The substance or drug is more lipophilic.
p.4
Drug Transport Mechanisms
What is transcellular drug transport?
The passage of drug through cells.
p.3
Drug Excretion Processes
What is the process of drug excretion?
Passive filtration of drugs from the body.
p.2
Cell Membrane Structure
Where are the hydrophilic heads of phospholipids located?
Towards the aqueous environment.
p.7
Passive Diffusion Characteristics
What factors determine passive permeability of drugs?
Drug size, lipophilicity, and charge/degree of ionization.
p.16
Active Transport Mechanisms
What is active transport?
A process that moves molecules against their concentration gradient using energy.
p.16
Active Transport Mechanisms
What is the primary function of active transport in cells?
To maintain concentration gradients of ions and molecules across the cell membrane.
p.16
Active Transport Mechanisms
What is an example of active transport in human cells?
The sodium-potassium pump (Na+/K+ pump).
p.9
Passive Diffusion Characteristics
In what environment do weak bases permeate more easily?
In an acidic environment.
p.3
Drug Absorption Mechanisms
Why is the small intestine significant for drug absorption?
It has a high surface area, which allows for better absorption.
p.17
Endocytosis Types and Functions
What is the role of receptors in endocytosis?
They are necessary for the selective uptake of molecules.
p.2
Hydrophilic vs. Hydrophobic Properties
How do hydrophilic substances behave in non-polar solvents?
They are very insoluble in non-polar solvents.
p.9
Passive Diffusion Characteristics
What does the pH partition hypothesis state?
Only unionized nonpolar drugs penetrate the membrane, and at equilibrium, their concentrations are equal on both sides.
p.3
Drug Transport Mechanisms
What must all drugs do to elicit a systemic response?
Pass through one or more membranes between the site of administration and the site of action.
p.1
Drug Transport Mechanisms
What is one of the sources for the course material?
Applied Biopharmaceutics and Pharmacokinetics by Shargel, Leon.
p.3
Drug Distribution and Metabolism
What does drug distribution refer to?
The delivery of drugs into the target site of action.
p.12
Drug Transport Mechanisms
How does facilitated diffusion differ from active transport?
Facilitated diffusion does not require energy, while active transport does.
p.10
Passive Diffusion Characteristics
What does it mean for a membrane to be 'hard to cross'?
It indicates that only specific types of substances can pass through, often requiring them to be lipophilic.
p.9
Passive Diffusion Characteristics
Why do polar drugs have less absorption?
Because they are less able to penetrate the membrane.
p.3
Drug Absorption Mechanisms
What are the four main processes drugs undergo in the body?
Absorption, Distribution, Metabolism, and Excretion.
p.10
Passive Diffusion Characteristics
What is a key characteristic of membranes regarding passive diffusion?
Membranes have specific properties that affect the ability of substances to cross them.
p.10
Passive Diffusion Characteristics
What type of substances must be to cross certain membranes?
Lipophilic (fat-soluble) substances.
p.2
Hydrophilic vs. Hydrophobic Properties
What is the behavior of lipophobic substances in the cell membrane?
They fail to interact with hydrophobic environments.
p.7
Passive Diffusion Characteristics
How does membrane thickness affect absorption?
Increased membrane thickness decreases absorption.
p.14
Facilitated Diffusion and Carrier Proteins
What role do membrane channel proteins play in facilitated diffusion?
They serve as selective pores through which water crosses the plasma membrane.
p.5
Drug Transport Mechanisms
What type of molecules are transported via passive diffusion?
Lipid soluble molecules; low molecular weight (200 - 1000 g/mol).
p.4
Hydrophilic vs. Hydrophobic Properties
What is the relationship between partition coefficient and lipophilicity?
An increase in partition coefficient leads to an increase in lipophilicity.
p.5
Active Transport Mechanisms
What is a key characteristic of active transport?
It is energy dependent (ATP).
p.7
Passive Diffusion Characteristics
What is the significance of the environment's pH for drug ionization?
Weak acids may ionize in alkaline environments, affecting absorption.
p.2
Cell Membrane Structure
What characteristic does the cell membrane exhibit?
Semi-permeability, allowing selective passage of substances.
p.14
Passive Diffusion Characteristics
Which drugs are transported via passive diffusion?
Lithium, Furosemide, Vitamin C, and Caffeine.
p.5
Facilitated Diffusion and Carrier Proteins
Is energy required for facilitated diffusion?
No, it is non-energy dependent.
p.5
Facilitated Diffusion and Carrier Proteins
How does saturation occur in facilitated diffusion?
It is saturable at high concentrations.
