Pharmacokinetics

Question 1

Relationship: Vd, Dose, and Co

Answer 1

Vd = Dose/Co

Question 2

Relationship: Vd, half-life, total clearance

Answer 2

Vd ~ half life ~ 1/Cl

Question 3

Relationship: total clearance and body weight

Answer 3

Cl = BW^0.7

Question 4

first order kinetics

Answer 4

rate depends are concentration gradient

Question 5

drug transporters:

Answer 5

p-glycoprotein 1 (pgp), multidrug resistant protein (MDR 1), ABC transporter : transports emphipathic cationic and neutral subtrates, verapamil sensitive

organic anion transporter, probenecid sensitive

Question 6

how are proteins/monoclonal antibodies transported?

Answer 6

receptor mediated endocytosis

Question 7

advantages of topical administration

Answer 7

avoids 1st pass effect

drugs with sufficient lipophilicity and potency

Question 8

Drug structure with the following %BW:

1. 4% BW
2. 17% BW
3. > 58% BW

Answer 8

1. High MW (proteins)
2. small MW, polar
3. small MW, lipophilic

Question 9

Inducers of CYP450 (clears drugs faster)

Answer 9

cigarette smoke, barbiturates, steroids

Question 10

result of Phase II conjugating moieties

Answer 10

product is:

1. always greater in MW
2. more water soluble
3. more readily excreted in urine and bile
4. less therapeutic activity than drug

Question 11

how does congestive heart failure affect clearance

Answer 11

decrease hepatic blood flow, decreasing hepatic clearance by biotransformation

Question 12

equation: Cl, half life, Vd

Answer 12

Cl = (0.693*Vd)/ half-life

Question 13

equation: half life and Kel

Answer 13

half-life = 0.693/kel

Question 14

AUC =?

Answer 14

(bioavailability) * (dose)/ total clearance

Question 15

Css equation

Answer 15

Css = (k0/clearance)

Question 16

loading dose

Answer 16

loading dose = Css*Vd

Question 17

what is the accumulation if:

1. dosing interval < half-life
2. dosing interval = half-life
3. dosing interval > half-life

Answer 17

1. as dosing interval deceases, Css increases
2. Cmasss = 2 Co
3. no accumulation

Question 18

maintenance dose

Answer 18

(Cmax - Cmin)*Vd