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What is the product of O-dealkylation of phenacetin?
What is the product of O-dealkylation of phenacetin?
N-Dealkylation involves the removal of an alkyl group from a nitrogen atom.
N-Dealkylation involves the removal of an alkyl group from a nitrogen atom.
True
What type of biological activity is associated with the product of phenacetin O-dealkylation?
What type of biological activity is associated with the product of phenacetin O-dealkylation?
Analgesic activity
_______ is formed from the oxidative deamination of certain nitrogen mustards in neoplastic cells.
_______ is formed from the oxidative deamination of certain nitrogen mustards in neoplastic cells.
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Match the following compounds with their respective structures or activities:
Match the following compounds with their respective structures or activities:
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Which enzyme is primarily involved in N-Dealkylation processes?
Which enzyme is primarily involved in N-Dealkylation processes?
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O-dealkylation leads to an increase in analgesic activity of the original compound.
O-dealkylation leads to an increase in analgesic activity of the original compound.
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Identify the compound represented by 'X' in the N-Dealkylation products.
Identify the compound represented by 'X' in the N-Dealkylation products.
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What is the primary purpose of sulfasalazine?
What is the primary purpose of sulfasalazine?
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The reduction of thiamine aims to decrease its lipophilicity for better absorption into the CNS.
The reduction of thiamine aims to decrease its lipophilicity for better absorption into the CNS.
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What is the product of the azo reduction of sulfasalazine?
What is the product of the azo reduction of sulfasalazine?
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The process involving the cleavage by bacteria in the lower _____ results in the breakdown of sulfasalazine.
The process involving the cleavage by bacteria in the lower _____ results in the breakdown of sulfasalazine.
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Match the following compounds with their functions:
Match the following compounds with their functions:
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Which of the following best describes the role of GSH in disulfide reduction?
Which of the following best describes the role of GSH in disulfide reduction?
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The activation of sulfasalazine is an example of reductive activation by aerobic bacteria.
The activation of sulfasalazine is an example of reductive activation by aerobic bacteria.
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What is modified to reduce the toxicity of primaquine?
What is modified to reduce the toxicity of primaquine?
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What is essential for the activation of cyclophosphamide?
What is essential for the activation of cyclophosphamide?
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Cyclophosphamide activates without the involvement of liver homogenates.
Cyclophosphamide activates without the involvement of liver homogenates.
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What chemical process is illustrated by the presence of phosphoramidase?
What chemical process is illustrated by the presence of phosphoramidase?
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Cyclophosphamide required __________ in order to become effective.
Cyclophosphamide required __________ in order to become effective.
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Match the following compounds with their associated characteristics:
Match the following compounds with their associated characteristics:
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Which of the following is a characteristic of P-450?
Which of the following is a characteristic of P-450?
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Cyclophosphamide can function without hydrolysis.
Cyclophosphamide can function without hydrolysis.
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What are the resultant compounds when cyclophosphamide undergoes hydrolysis?
What are the resultant compounds when cyclophosphamide undergoes hydrolysis?
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What is the therapeutic index of the compound 8.116 compared to 8.115 in mice?
What is the therapeutic index of the compound 8.116 compared to 8.115 in mice?
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The chemical formula for __________ is associated with the components of cyclophosphamide activation.
The chemical formula for __________ is associated with the components of cyclophosphamide activation.
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Match the following values with their relevance in the context:
Match the following values with their relevance in the context:
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Acyclovir has an absorption rate of 50-60%.
Acyclovir has an absorption rate of 50-60%.
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Which drug is used as an anti-leukemia treatment?
Which drug is used as an anti-leukemia treatment?
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The compound that improves uptake in the liver is _____ .
The compound that improves uptake in the liver is _____ .
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Match the following drugs to their effects or characteristics:
Match the following drugs to their effects or characteristics:
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What enhances the oral absorption of acyclovir?
What enhances the oral absorption of acyclovir?
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Intracellular thiol levels are lower than in the blood for antimalarial compounds.
Intracellular thiol levels are lower than in the blood for antimalarial compounds.
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What enzyme does 6-mercaptopurine inhibit in the purine nucleotide biosynthesis pathway?
What enzyme does 6-mercaptopurine inhibit in the purine nucleotide biosynthesis pathway?
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What is the primary mechanism of action for acyclovir?
What is the primary mechanism of action for acyclovir?
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Acyclovir can be phosphorylated by uninfected cells.
Acyclovir can be phosphorylated by uninfected cells.
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What does acyclovir resemble in structure?
What does acyclovir resemble in structure?
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Acyclovir is a prodrug that must be activated by __________ before it can exert its effects.
Acyclovir is a prodrug that must be activated by __________ before it can exert its effects.
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Which enzyme is NOT involved in the phosphorylation of acyclovir?
Which enzyme is NOT involved in the phosphorylation of acyclovir?
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Match the following components with their roles in the activation and action of acyclovir:
Match the following components with their roles in the activation and action of acyclovir:
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Acyclovir triphosphate can effectively enter normal cells after being released.
Acyclovir triphosphate can effectively enter normal cells after being released.
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What is the outcome of incorporating acyclovir into viral DNA?
What is the outcome of incorporating acyclovir into viral DNA?
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Study Notes
N-Dealkylation
- N-dealkylation is a metabolic reaction where an alkyl group is removed from a nitrogen atom
- This reaction is often catalyzed by cytochrome P450 enzymes
- An example of this reaction is the metabolism of alprazolam and triazolam
- In these examples, the chlorine atom (X) can be either present or absent
O-Dealkylation
- O-dealkylation is a metabolic reaction where an alkyl group is removed from an oxygen atom
- This reaction is often catalyzed by cytochrome P450 enzymes
- An example is the metabolism of phenacetin to acetaminophen
- Phenacetin is an analgesic, while acetaminophen is the active metabolite
Oxidative Deamination
- Oxidative deamination is a metabolic reaction where an amino group is removed from a molecule
- This reaction is often catalyzed by cytochrome P450 enzymes
- The reaction is important for the activation of certain drugs, including cyclophosphamide
- Cyclophosphamide is an anti-cancer drug
- It is activated by enzymes found in neoplastic (cancer) cells
- Cyclophosphamide is converted into a reactive metabolite that can damage DNA
Reductive Activation
- Reductive activation is a metabolic reaction where a molecule is reduced
- This reaction is often catalyzed by enzymes found in bacteria
- An example is the metabolism of sulfasalazine
- Sulfasalazine is used to treat inflammatory bowel disease
- The drug is reduced to sulfapyridine, which is the active metabolite
Disulfide Reduction
- Disulfide reduction is a metabolic reaction where a disulfide bond is broken
- This reaction can be catalyzed by enzymes or occur nonenzymatically.
- An example is the metabolism of thiamine
- Thiamine is poorly absorbed into the central nervous system (CNS)
- Reduction of the disulfide bond in thiamine makes it more lipophilic, increasing absorption into the CNS
Nucleotide Activation
- Nucleotide activation is a metabolic reaction where a nucleotide is activated
- This reaction is often catalyzed by enzymes
- An example is the metabolism of 6-mercaptopurine
- 6-mercaptopurine is an anti-leukemia drug
- It is activated by enzymes that convert it to its active nucleotide metabolite
- This metabolite inhibits enzymes involved in purine nucleotide biosynthesis
Adenosine Deaminase
- Adenosine deaminase is an enzyme that catalyzes the deamination of adenosine
- Acyclovir is a drug that inhibits adenosine deaminase
- Acyclovir has poor oral absorption, leading to the development of prodrugs
- Prodrugs are designed to increase oral absorption
Phosphorylation Activation
- Phosphorylation activation is a metabolic reaction where a molecule is phosphorylated
- This reaction is often catalyzed by enzymes
- An example is the activation of acyclovir
- Acyclovir is a drug that inhibits viral DNA polymerase
- Acyclovir is selectively toxic to virus-infected cells due to phosphorylation by viral thymidine kinase
- Sequential phosphorylations by viral enzymes convert acyclovir into its active triphosphate form
- Acyclovir triphosphate inhibits viral DNA polymerase, but not normal DNA polymerase
- Once incorporated into viral DNA, the triphosphate form of acyclovir creates a dead-end complex, preventing further replication
- The acyclovir triphosphate is too polar to be taken up by normal cells
- This selective toxicity allows acyclovir to target and destroy viruses without harming normal cells
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Description
Explore the fascinating metabolic reactions including N-dealkylation, O-dealkylation, and oxidative deamination, all catalyzed by cytochrome P450 enzymes. This quiz will test your understanding of these reactions and their significance in drug metabolism. Gain insights into the metabolism of substances like alprazolam, phenacetin, and cyclophosphamide.
