Pharmacokinetics Lecture 2: Distribution & Metabolism

What is the main cause of the initial rapid fall in plasma concentration during drug distribution?

What factor influences drug distribution by increasing it?

What is the importance of drug metabolism in pharmacokinetics?

What role does cytochrome p450 system play in pharmacokinetics?

Which of the following can easily cross the blood-brain barrier?

What does the volume of distribution (Vd) of a drug refer to?

Which organ is primarily responsible for drug metabolism?

What is the function of Phase I biotransformation?

What do cytochrome P450 enzymes primarily do in drug metabolism?

Match the following terms with their meanings:

Match the following cell types with their locations:

Match the following terms with their descriptions:

The blood-brain barrier (BBB) hinders the distribution of most drugs to the central nervous system (CNS) and prevents tissue distribution, leading to drug-drug interactions when two drugs compete for the same binding site.
Lipid-soluble drugs can easily cross the BBB.
The volume of distribution (Vd) of a drug refers to the hypothetical volume in the body that contains the drug other than plasma.
The protein binding of a drug can prevent its tissue distribution and lead to drug-drug interactions if two drugs compete for the same binding site.
Plasma proteins, such as albumin and alpha-1 acidic glycoprotein, bind to drugs and influence their distribution.
Drug metabolism is essential for drug clearance and renal elimination of metabolites, and may produce active and/or toxic metabolites.
The liver is the primary site of drug metabolism.
Phase I biotransformation (hydrolysis) exposes functional groups of drugs, making them more water-soluble and easier to excrete.
Phase II biotransformation (conjugation) increases the water solubility and ionization of drugs, enhancing their renal and biliary excretion and producing pharmacologically inactive compounds.
Cytochrome P450 enzymes play a key role in drug metabolism, particularly in the liver, and are involved in drug-drug interactions.
Acetaminophen/paracetamol undergoes glucuronide conjugation as a major metabolic pathway.
Cyp450 enzymes can be inducers or inhibitors of drug metabolism, affecting the clearance and half-life of other drugs.
Phenobarbital is an inducer of several cytochrome P450 enzymes, while cimetidine inhibits many of them, affecting the activity of warfarin.

Study the principles of drug distribution and metabolism in pharmacokinetics with this lecture. Learn about the factors affecting distribution, apparent volume of distribution, drug metabolism, and the role of cytochrome p450 system in drug interactions.