57 Questions
What is the primary location of liver cells in relation to capillaries for drug delivery?
Right adjacent to the capillaries extending from the central vein
What is the primary purpose of Phase-II metabolism in biotransformation?
To increase the overall polarity of a molecule
Where are the Cytochrome P450 enzymes primarily found in hepatocytes?
Mitochondria and smooth endoplasmic reticulum
How many gene families are responsible for drug metabolism among the 63 Cytochrome P450 genes?
3 families
What is the primary type of reaction in Phase-I metabolism?
Oxidation reaction
What is the primary function of microsomes in liver metabolism?
To isolate and concentrate Cyp P450 enzymes
Which of the following reactions is NOT an example of a Phase-I reaction?
Glucuronidation
Where can extrahepatic metabolism occur?
In blood and other tissues
What is the primary difference between microsomal and non-microsomal liver metabolism?
The presence or absence of Cyp P450 enzymes
What type of enzyme is involved in peptide bond hydrolysis?
Peptidases
What is the name of the enzyme involved in dehalogenation reactions?
None of the above
What is the primary goal of drug metabolism?
To increase the polarity of the molecule
Which organ is responsible for the majority of drug metabolism?
Liver
What is the name of the functional unit in the liver where most metabolism takes place?
Liver lobule
What is the percentage of cardiac output that goes to the liver?
25%
What is the approximate blood flow rate to the liver?
1.5 L/min
How many liver lobules are present in the human liver?
50,000 to 100,000
Which type of reaction involves the conversion of the parent drug to a new molecule?
Phase-I Reaction
What type of oxidation is mediated by Cytochrome P450 enzymes?
All of the above
Which of the following is an example of a Phase-II reaction?
Glucuronidation
What is the result of the acetylation process in Phase-II metabolism?
A more polar compound
Which enzyme is involved in the hydrolysis of esters and amides?
Esterases
What is the prosthetic group used by Monoamine Oxidase (MAO) for delivering oxygen?
Flavin adenine dinucleotide (FAD)
Which enzyme family is involved in reducing ethanol and other endogenous/exogenous alcohols?
Alcohol Dehydrogenase
What is the primary function of Xanthine Oxidase?
To oxidize purines
Which co-factor is used by Monoamine Oxidase (MAO) for its catalytic activity?
Flavin adenine dinucleotide (FAD)
What is the primary function of Monoamine Oxidase (MAO) in neurotransmitter regulation?
To degrade and regulate neurotransmitters
What is the primary type of reaction involved in Phase-I metabolism?
Oxidation
What is the name of the enzyme family primarily responsible for Phase-I metabolism?
Cytochrome p450
What is the purpose of Phase-II metabolism in biotransformation?
To increase the polarity of a molecule
Where are the Cytochrome p450 enzymes primarily found in hepatocytes?
Mitochondria and smooth endoplasmic reticulum
What is the major metabolizing organ responsible for drug metabolism?
Liver
What is the primary function of UDP-glucuronyl transferase in Phase-II metabolism?
To conjugate glucuronic acid with hydroxyl or carboxyl groups
What is the role of CYP3A4 in Phase-I metabolism?
To oxidize substrates, such as buspirone
What is the purpose of acetylation in Phase-II metabolism?
To conjugate acetyl-CoA with amines
What is the result of glucuronidation in Phase-II metabolism?
The formation of a more hydrophilic compound
What is the purpose of Phase-II metabolism?
To conjugate compounds with hydrophilic groups, increasing their water solubility
What is the direction of movement of small lipid-soluble molecules during passive diffusion?
From an area of high to low concentration
What is the primary function of human serum albumin (HSA) in the bloodstream?
To bind and transport drug molecules
What is the characteristic of phospholipid molecules that allows them to form a membrane?
They are amphipathic and have a hydrophobic tail and a hydrophilic head
What is the result of a drug molecule binding to a plasma protein?
The molecule is unavailable for binding to pharmacological targets
What is the primary factor that determines the ability of a molecule to cross a phospholipid membrane?
The lipophilicity of the molecule
What is the primary mechanism that allows lipophilic molecules to pass through the plasma membrane?
Passive diffusion
Which type of molecules have a harder time passing through the fatty cell membranes?
Hydrophilic
What is the characteristic of the plasma membrane that allows it to selectively permeable?
It is selectively permeable to lipophilic molecules
What is the primary function of active transport in the context of drug delivery?
To facilitate the movement of molecules across the membrane
What is a characteristic of lipophilic molecules in the context of drug delivery?
They are more permeable than ionized or polar molecules
What is the direction of movement of molecules in active transport?
From low to high concentration
What is a characteristic of a saturable active transport system?
It has a specific binding site on the carrier
What is required for active transport to occur?
Energy, such as ATP
Which of the following is an example of a drug that is well-absorbed despite being an acid?
Penicillin
What type of molecules are more likely to be transported via active transport?
Ionized molecules
What is the primary purpose of plasma protein binding in pharmacokinetics?
To retain the drug in the plasma compartment
What is the primary determinant of passive diffusion across a phospholipid membrane?
Lipid solubility of the drug
According to Fick's Law, what is the direction of diffusion?
From higher concentration to lower concentration
What is the optimal range of LogP for a compound to have high oral bioavailability?
0 < LogP < 3
What is the definition of lipophilicity?
The tendency of a compound to partition in a nonpolar lipid matrix
Learn about the process of drug metabolism, how it affects clearance and bioavailability, and the chemical modifications that occur to increase water solubility and facilitate elimination.
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