Exam1Lec1Pharmacokinetics

Question 1

What are two main concepts about drugs

Answer 1

1. Drugs mask problems, not solve them
2. All drugs are poison at high concentration

Question 2

What are pharmacokinetics?

Answer 2

The process by which drugs are absorbed, distributed within the body, metabolized, and excreted

Question 3

Absorption

Answer 3

process which drugs enter systemic circulation

Question 4

100% of a drug is absorbed if administered?

Answer 4

IV

Question 5

Distribution

Answer 5

drugs reach its site of action

Question 6

Elimination

Answer 6

process where drugs are enzymatically altered (biotransformation) mainly in liver and excreted in kidneys

Question 7

Only _____ drugs can cross the BBB

Answer 7

highly lipid soluble/non-ionized

hydrophobic

Question 8

Factors in transfer of drugs across membranes

Answer 8

1. molecular size and shape
2. lipid: water partition coeffic. (solubutlity of drug)
3. most drugs are WA or WB

Question 9

determines solubility of the drug and affects distribution

Answer 9

lipid:water partition coefficient

Question 10

Nonionized drugs ____ cross the cell membrane. Ionized drugs ____ cross.

Answer 10

can, cannot

Question 11

weak acid ___ an H+ ion

Answer 11

gives

equation goes to the right becaause lower pH means more H+ pushing the equation twoards unionized form

Question 12

weak base ___ an H+ ion

Answer 12

takes

Question 13

strong acids ____ compared to WA

Answer 13

completely dissociate

Question 14

For weak acid, the degree of ionization depends of what?

Answer 14

pH

Question 15

decrease pH = ___ more ionized

Answer 15

base

Question 16

increase pH = ____ more ionized

Answer 16

acid

Question 17

Only the ____ form of the drugs can readily cross the cell membrane

Answer 17

non-ionized (HA/B)

no charge so free to go around

Question 18

Henderson-Hasselbalch equation: Weak acid vs. WB

Answer 18

WA:
pH = pKa + log10 (I/U)
WB:
pH = pKa + log10 (U/I)

remember I owe U for WA
HH eq allows the calculation of degree of the ionization for weak acids or weak bases

Question 19

Term for when drugs become trapped on one side of a lipid mucosal barrier

Answer 19

ion trapping

Question 20

weak acids get trapped on ____ side

Answer 20

basic

Question 21

weak bases get trapped on ____ side

Answer 21

acidic

Question 22

Processes of drug transfer

Answer 22

1. Passive diffusion
2. Active transport
3. Facilitated diffusion

Question 23

Passive diffusion:
1. movement on gradient?
2. saturable?
3. carrier mediated?
4. extra detail?

Answer 23

high to low [ ] (down graidient)
NOT saturable
NOT carrier med
it is the most common and the higher the lipid: water partition coefficient the faster is the passive diffusion

ex: ethanol

Question 24

Active transport:
1. movement on gradient?
2. saturable?
3. carrier mediated?
4. extra detail?

Answer 24

Low to High (up gradient) (only transport that does this)
Saturable
Carrier mediated
Needs Energy

ex: penicillin in kidney p-glycoprotein and MRP are the main transporters of drugs

Question 25

What are xenobiotics?

Answer 25

Foreign chemical substance that goes through active transport

Question 26

What does fixed capacity mean?

Answer 26

You reach vmax so you cant go higher than that

Question 27

Faciliated diffusion: 1. movement on gradient? 2. saturable? 3. carrier mediated?

Answer 27

High to low ( down gradient) Saturable Carrier mediated ## Footnote ex: amino acids transport into brain

Question 28

What is bulk flow?

Answer 28

movement of molecules through capillary junction

Question 29

What is pinocytosis?

Answer 29

Formation and movement of vesicles. it plays a minor role in drug transport across the membrane

Question 30

What are the factors that affect drug absoprtion?

Answer 30

solubility, concentration, circulation, surface area, time

Question 31

Drug absorption: Solubility

Answer 31

aqueous solution vs. oily solution pH (ex: aspirin)

Question 32

How does Concentration affect drug absoption?

Answer 32

high concentration of drug absorbed more quickly

Question 33

How does circulation affect affect drug absoprtion?

Answer 33

increase circulation = increase absorption decrease circulation = decrease absorptions

Question 34

Drug absorption: Surface Area

Answer 34

Intestinal mucosa = oral meds Pulm. alveolar epithelium = anesthetics Skin = patches ## Footnote antibitoics get through bodies through lungs