Pharmacokinetics

Question 1

What is pharmacokinetics

Answer 1

the study of the effect the body has on the drug

Question 2

What are the different transports of the drugs?

Answer 2

through either active or passive transport

Question 3

What are the active transports

Answer 3

a process that moves against the gradient low to high. IT uses the energy of ATP to move molecules from low to high concentration. For some of the types of transporters, they may be a SLC or ABC transporters to help with the process. The types of transport are: facilitated and drug transporters

Question 4

What are the passive transports

Answer 4

it is a process where molecules use the force of the gradient (which is high to low Concentration) to move molecules from one region to another. Types are: diffusion and paracellular

Question 5

What molecules can diffuse cross the membrane

Answer 5

gases, small polar and hydrophobic molecules

Question 6

What molecules cannot diffuse cross the membrane

Answer 6

large polar and charged molecules

Question 7

What are SLC transporters

Answer 7

it is a type of transporter that is usually seen in facilitative transport. it is active in the secondary active transport of het he antiport (Na and Ca exchanger) and the symport ( Na/Glucose transporter in the GI)

Question 8

What are ABC transporters

Answer 8

they are transporters that utilize the energy of ATP binding and hydrolysis to carry out certain biological processes across membrane. it is in primary active transport.

Question 9

What is bioavailability

Answer 9

In pharmacology, Bioaviilabilty is the fraction of administered drug that reaches the system circulation. for ex. 100 mg of drug is administered orally and 70mg is absorbed, then the bioavailiabilty is 70%.

Question 10

What are the factors that influence bioavailability?

Answer 10

First pass hepatic bioavailabilty
solubility of the drug
chemical instability
nature of the drug formulation

Question 11

What are phase 1 reactions

Answer 11

reactions that render a molecule more polar by attaching an ionizable group to the molecule. characteristics are OH, NH2 and SH. after phase 1 reaction drug effects weakens. prodrug are converted to active form ex.

Question 12

What are phase 2 reactions

Answer 12

reactions that render the molecule more polar by attaching a polar molecule to the parent compound

Question 13

What is the 4 parts of Pharmokinetics

Answer 13

absorption
distribution
Metabolism
Elimination

Question 14

What is absorption

Answer 14

site or route of the administration ( directly or indirectly) into the bloodstream

Question 15

What are the factors that play into the rate and efficacy of the absorption of the drug

Answer 15

environment
the drug characteristics
route of administration

Question 16

What is Distribution

Answer 16

it deals with the movement of the drug once in the plasma. it has the option to move or reverse and leave the bloodstream and go to the interstitial and intracellular fluids

Question 17

What is the metabolism

Answer 17

How the drug is handed biochemically by the body

Question 18

What is excretion

Answer 18

deals with how the drug leaves the body through either bile, urine or feces

Question 19

What is facilitated diffusion

Answer 19

is the movement of large molecules from high to low concentration due to the transmembrane carrier proteins that go through a conformational change to bring the molecules in the interior of the cel

Question 20

What are the factors that influence absorption

Answer 20

effect of pH on drug absorption 
blood flow 
total surface area 
contact time at the absorption surface 
Expression of P-glycoprotein

Question 21

What are the function of the P-glycoprotein

Answer 21

it is a transmembrane transporter protein that is responsible for transporting various molecules like drugs across the membrane.

Question 22

What is first pass effect

Answer 22

is a phenomenon of drug metabolism whereby the concentration of a drug is greatly reduced before it reaches the systemic circulation due to the gut wall or the liver metabolizes the drug rapidly.

Question 23

what type of drug is typically readily to diffuse across the membrane hydrophobic or hydrophilic

Answer 23

hydrophobic

Question 24

What is the volume of distribution

Answer 24

the volume of distribution (VD, also known as apparent volume of distribution) is the theoretical volume that would be necessary to contain the total amount of an administered drug at the same concentration that it is observed in the blood plasma.[1] It is defined as the distribution of a medication between plasma and the rest of the body after oral or parenteral dosing.[2]

The VD of a drug represents the degree to which a drug is distributed in body tissue rather than the plasma.

Question 25

What is the correlation between the Vd and the tissue concentration

Answer 25

VD is directly correlated with the amount of drug distributed into tissue; a higher VD indicates a greater amount of tissue distribution. A VD greater than the total volume of body water (approximately 42 liters in humans[3]) is possible, and would indicate that the drug is highly distributed into tissue.

Question 26

What are the 3 compartments that the drug can distribute to after being administered?

Answer 26

Plasma compartment
Extracellular fluid
Total body water

Question 27

What is plasma compartment

Answer 27

this tends to happen to molecules that are to large to move effectively out to the capillaries thus making it stuck in the plasma this distribute through 6% of the body.

Question 28

What is extracellular compartment

Answer 28

if the molecules are small but hydrophilic, then the molecules can move into the intestitial fluid. this distributes through 20% of the body

Question 29

What is the total body water

Answer 29

• if the molecules are small and they are hydrophilic it can move all the way through the intracellular fluid and it distributes through 60% of the body.

Question 30

What is the formula for Vd

Answer 30

Vd= dose/ C0

Question 31

What is the relationship between Vd and the half life

Answer 31

drug elimination depends on the amount of drugs delivered to the liver or kidney. it depends on the blood flow and the fraction in the plasma. If Vd is high than the half life of the drug is high and extend the duration of action of the drug.