Pharmacokinetics

Question 1

Process involved (LADME)

Answer 1

Pharmacokinetics
Transport
Liberation
Absorption
Distribution
Metabolism
Excretion

Question 2

▪️ movement through the cell membrane
▪️ basic requirement: drug must be in aqueous solution except in pinocytosis where drug is in missile form

Answer 2

Transportation

Question 3

Two types of mechanism of transport in Pharmacokinetics

Answer 3

1. Passive Diffusion
2. Carrier-mediated Transport

Question 4

▪️ dominant, most common; slowest; no enery requirement
▪️ along concentration gradient (high to low)
▪️ governed by Fick’s Law Diffusion

Answer 4

Passive diffusion

Question 5

“LUNA”

Answer 5

Lipophilic
Unionized
Non-Polar
Absorbed

Question 6

“HIPE”

Answer 6

Hydrophilic
Ionized
Polar
Excreted

Question 7

▪️ selectivity/ specificity- carriers recognize specific molecules
▪️ subject to competition, inhibition or antagonism
▪️ Michaelis-Menten Kinetics/ non-linear kinetics/ capacity limited

Answer 7

Carrier-Mediated Transport

Question 8

Drug that crosses the BBB because of large neutral AA transporter (LNAAT)

Answer 8

Levodopa

Question 9

Elimination is DEPENDENT on drug concentration

Answer 9

First Order

Question 10

▪️Drug clearance is on a constant rate
▪️INDEPENDENT on drug concentration

Answer 10

Zero Order

Question 11

Energy requiring; against concentration gradient (uphill); fastest

Answer 11

Active Transport

Question 12

No energy requirement; along concentration gradient; passive diffusion with carrier

Answer 12

Facilitated Diffusion

Question 13

Drug passes through water filled pores; only paracellular transport mechanism

Answer 13

Convective Transport / Bulk Flow

Question 14

Important for movement or transport of large ions

Answer 14

Ion-Pair Transport

Question 15

▪️ release of drug from the dosage form
▪️ end product: drug in aqueous form/sol’n
▪️ highly modifiable

Answer 15

Liberation

Question 16

▪️Physiologic: rate and extent of drug disappearance from the site of administration
▪️Pharmacokinetic: rate and extent of drug entry into the systemic circulation

Answer 16

Absorption

Question 17

Is the measure of rate and extent of drug entry into the systemic circulation / pharmacokinetic absorption

Answer 17

Bioavailability [BA] or [F]

Question 18

2 Methods of Bioavailability

Answer 18

1. Cumulative Urinary Excretion Data
2. Drug Plasma Concentration vs Time Graph

Question 19

Maximum plasma concentration; measures both rate and extent of absorption; most variable

Answer 19

Cmax

Question 20

Time it takes to reach Cmax; measures rate only; least important

Answer 20

Tmax

Question 21

Area under the curve; measures extent only; most important

Answer 21

AUC

Question 22

Types of BA

▪️ same dose, different routes

Answer 22

Absolute Bioavailability

Question 23

Types of BA

▪️ use when comparing a generic drug to a reference standard
▪️ same dose, same route particularly PO

Answer 23

Relative Bioavailability

Question 24

Main site of drug absorption

Answer 24

Small intestine

Question 25

Time it takes the stomach to empty its contents into the small intestine Normal: 2-3 hours

Answer 25

Gastric Emptying Time (GET)

Question 26

Faster Emptying, Faster Absorption, Lower

Answer 26

Lower GET

Question 27

What Factors Increasing GET (slower absorption)

Answer 27

▪️high fat / protein meal, happy meal ▪️ stress ▪️ strenuous exercise (heavy) ▪️ gastric ulcers ▪️ lying on the LEFT side ▪️ anticholinergics, opioid, morphine, nalbuphine

Question 28

What Factors Decreasing GET (faster absorption)

Answer 28

▪️ extreme temperature of food ▪️ mild exercise ▪️ DM ▪️ lying on the RIGHT side ▪️ cholinomimetics ▪️ prokinetics: domperidone metoclopramide

Question 29

▪️ SAME API, salt / ester / complex and dosage form and strength ▪️ DIFFERENT in excipients used such as flavorants and colorings

Answer 29

Pharmaceutical Equivalents

Question 30

▪️SAME API ▪️DIFFERENT salt/ester/complex, dosage form & strength

Answer 30

Pharmaceutical Alternative

Question 31

▪️SAME API in the same dosage form and route of administration ▪️ Similar bioavailability

Answer 31

Therapeutic Equivalents

Question 32

▪️SAME drug class ▪️DIFFERENT API

Answer 32

Therapeutic Alternatives

Question 33

Reversible transfer of a drug from the systemic circulation to the site of action and to the other compartment

Answer 33

Distribution

Question 34

Pharmacokinetic Parameters: Hypothetical value of body fluid required to dissolve a given amount of drug concentration equal to that of plasma concentration

Answer 34

Volume of distribution (Vd)

Question 35

Drugs that undergo extensive protein binding (WNMS)

Answer 35

Warfarin NSAIDs (Phenylbutazone) Midazolam Sulfa drugs

Question 36

▪️Biotransformation ▪️Primary Goal: to convert drugs into an inactive / less active non-toxic / less toxic polar, water soluble

Answer 36

Metabolism

Question 37

Initially inactive

Answer 37

Prodrug

Question 38

Aka Pre-systemic metabolism

Answer 38

First Pass Effect

Question 39

▪️Final loss drug from the body ▪️Requirement: polar, water soluble

Answer 39

Excretion

Question 40

▪️Main excretory organ ▪️Requirement: Polar; Low MW <400-600

Answer 40

Kidneys

Question 41

▪️Slow Acetylators ▪️Fast Acetylators

Answer 41

▪️Caucasians ▪️Asians